“bicycle batteries |battery electric bike”

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C values seem to be as much about cell packaging as chemistry for LiFePo/LiMn/LiNiCoMn Pouch and prismatic cells with high AHr per cell tend to have a C value of about 1 to 1.5. So cheap packs both cased and shrink wrapped or from suppliers like Ping seem to be like this. Cylindrical cells from A123 or Headway tend to have C values of 3C to 5C upwards. And for a fully built pack, C is as much about cells in parallel as anything. eg 10s2p having twice the C of 10s1p Again BMSBattery/GreenBikeKit are now selling LiFePo Headway based packs with a BMS and with C values of 3C to 5C and either cased or shrinkwrap.

I’d recommend going with a cell that can output 10A, giving you 40A continuous power rating. You’ll use less than that, meaning the cells will be happier (and cooler). Something like the Sanyo 18650GA or LG MJ1 would give you good power and capacity (both are around 3,400 mAH per cell).

Technically yes, you can bypass the BMS for discharging and just charge through the BMS but this is not recommended. It is better to just choose a BMS that can handle your 50A discharge. BesTechPower makes some great BMS units that can handle 50A and more, depending on the model. They have many options.

An older battery technology that was popular around 10 years ago as replacment for lead acid in some more expensive commercially available e-bikes. Today it has been obsoleted  in e-bike applications because of the recent availability of LiPo and LiFePO4 cells. NiMH is a finicky technology to deal with. The packs do not have long life expectancy, and have to be treated delicately. One big problem for DIYers is that its very hard to safely charge NiMh cells that have been soldered together in parallel. Extra care is needed for NiMH in both assembling and charging.

Most of the problems occur when charging an ebike because they are unsupervised and that is when a LiPo fire can burn down a house etc. Use common sense on where you are going to charge your bike or battery pack, so that if it does burst into flames it does not take your house with you. I have a big steel barbecue grill set up in my entryway which  I charge my battery packs in  as nice safeguard.  This involved taking the battery pack out of the bike after each ride but I am OK with that:

Work in a clean area free of clutter. When you have exposed contacts of many battery cells all wired together, the last thing you want is to accidentally lay the battery down on a screwdriver or other metallic object. I once nearly spilled a box of paperclips on the top of an exposed battery pack while trying to move it out of the way. I can only imagine the fireworks show that would have caused.

Note that in the article it says that LiFePo is the most commonly used chemistry. I think that depends on where you are looking. I suspect that LiNiCoMn or the older LiMn is actually most common in terms of total unit cells because they’re the cheapest and get used in the low end E-Bike market in China.

When it comes to layout, there are two ways to assemble cells in straight packs (rectangular packs like I am building). I don’t know if there are industry terms for this, but I call the two methods “offset packing” and “linear packing”.

I assume you mean 52V (14s, or 14 cells in series) which is a somewhat common lithium ion battery configuration. It works with most 48V setups but provides a little more power than a standard 48V (13s or 13 cell) battery. A good charger I recommend for 52V 14s batteries is this one.

Interesting that they claim the controller is balancing the two batteries. I highly suspect that is false, and just marketing fluff, but who knows. They probably have a simple diode built into the internal battery. I checked with a friend and he reminded me that it would be a good idea to include a diode in the discharge cable of your auxiliary battery. That way if you ever plugged in your auxiliary battery when it was low on charge and the bike was fully charged, the bike wouldn’t try to charge your auxiliary battery in reverse.

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In general, the size and cost of a cell will scale directly with its amp-hour capacity. To a first order, twice the amp-hours would mean twice the size, twice the weight, and twice the cost. In practice this deviates a little due to different packing densities and production scales, but it’s usually pretty close. For instance, the familiar ‘AA’ NiMH has about 2 Ah, a ‘C’ cell has 4 Ah, a ‘D’ cell is about 8Ah, the large ‘F’ cells are 12-13 Ah, and double-D cells are 18-19Ah.

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NO Memory Effect to reduce the capacity over time, longer life, more eco-friendly 1.5V / 1200MAH – Same as regular AA battery For toys, game controller, wireless mouse, wireless keyboard, remote and so on SAFE & ECO & NON TOXIC – Approved by FCC CE & RoHS, the 1200mAH AA lithium batteries are guaranteed

The higher C-rate of 3C for the newer LiFePO4 (from A123) keeps these popular so you don’t need a huge pack to get fairly adequate amps. To get a continuous 24A, you’d only need a 8-Ah battery. Fairly affordable, and small enough to fit in a bike frame.

Now take your trip distance, multiply it by the appropriate watt-hours/km from the table above, and you’ll get the total minimum watt-hours required for the trip. Take the watt-hours you’ve estimated and divide it by the voltage, and you now have an estimate on the minimum amp-hours you’ll need from the pack.

Linear packing, on the other hand, will result in a narrower pack that ends up a bit longer than offset packing. Some people say offset packing is more efficient because you can fit more cells in a smaller area by taking advantage of the space between cells. However, offset packing creates wasted space on the ends of parallel group rows where gaps form between the edge of the pack and the ‘shorter’ rows. The larger the battery pack, the less wasted space is taken up compared to the overall pack size, but the difference is negligible for most packs. For my battery, I decided to go with offset packing to make the pack shorter and fit easier into a small triangle bag.

One other disadvantage of lithium batteries that isn’t talked about often, but should be, is their potential for theft. Lithium ebike batteries have become huge targets by bike thieves as a result of their combination of small size and high price tags (the same factors that keep shaving razor cartridges behind lock and key at the drug store). Thieves see an easy target and ample resale market, meaning you have to be extra careful about locking your ebike up and leaving it alone in public.

Should the voltage on the charger be exact, or can it be *higher* than my battery pack? For example, I need to charge a 19.2V pack. Does my charger have to *exactly match* (or come as close to as possible to) this 19.2V, or can I use a higher voltage charger, (say, 36V)? Will the charger automatically adjust to a lower voltage, allowing a 36V charger to charge my 19.2V pack?

1. The extra amperage that the battery could output isn’t wasted, it’s just sort of a safety factor. It means you aren’t stressing the battery to its limit. Also, batteries only get their full rated capacity at lower discharged. So you’re more likely to get the full capacity now than if you actually pulled 50A out of it.

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A cell that provides close to a “real world” 2.8-Ah per 18650 cell is pretty impressive, and the 3C current-producing capability is perfect for E-bikes (a 15-Ah pack can provide a continuous 45A, and our favorite power level of 30A can be provided by a very small 10-Ah pack). If you know of anyone who builds a pack out of these, please contact us, as we are very keen to discover whatever strengths or weaknesses they may have. If you are shopping to buy these, make certain you get these specific part numbers, because similar part numbers will only have half the C-rate.

It was an interesting project to say the least, particularly how to link the Ch- and the P- from the BMS taking its B- from the 7s negative termination to the positive of the 6s group, given that there are two routes (i.e. charging and discharging), so connecting both simultaneously would override the function of the BMS.

This is a very simple layout where each column of 3 cells is connected in parallel and then the 10 columns are connected across in series from left to right. The BMS board is shown at the far right end of the pack. You’ll see how the pack represented in the drawing will come together in real life shortly.

Many people are tempted to use cheaper 18650’s sold under names like Ultrafire, Surefire and Trustfire. Don’t be one of those people. These cells are often marketed as up to 5,000 mAh but struggle to get more than 2,000 mAh. In actuality, these cells are just factory rejects, purchased by companies like Ultrafire and repackaged in their own branded shrink wrap. These B-quality cells are then resold for use in low power devices like flashlights where their weaker performance is less of an issue. If a cell costs less than $2, it simply isn’t worth it. Stick to the name brand cells, like my favorite Samsung cells, if you want to build a safe, quality ebike battery.

Now this step is very important: I’m going to turn the pack upside-down and perform this set of welds between the positive caps on the second parallel group and negative terminals on the third parallel group. Essentially, I’m welding on the opposite side of the pack as I did when I connected the first two parallel groups. Skip down a few pictures to see the completely welded pack to understand how the alternating side system works.

If you want to step up a notch on the quality ladder, here is another good charger that I prefer even more, though it’s a bit more expensive: http://www.aliexpress.com/store/product/aluminum-shell-36V-42V-2Amper-Li-ion-Lipo-battery-charger-high-quality-charger-for-10S-li/1680408_32275847257.html

To calculate the max amps the battery can deliver, you have to know the max amps of the cells you used. For example, Panasonic 18650pf cells can deliver 10A continuous, and I used 3 batteries electric bikes in series in this battery, so the battery can deliver 3 x 10A = 30A. However, you also need to know how much current the BMS can deliver. If I put a 15A continous BMS on this pack then that would be the “weakest link” so to speak, meaning the pack with the BMS could only deliver 15A continuous.

“lithium bike battery +batteries for electric bicycles”

Yes, I’ve seen this problem. Homes that have only a 10A circuit breaker are often not enough for these welders. The room I wanted to use mine in had a 10A, so I switched it for a 20A breaker at the breaker box and now it works fine.

Hello Micah: Thanks for this most interesting and useful article! I want to build a battery in a 39mm x 520mm seatpost for fueling a 250W motor that normally uses a 7.2 Ah – 25 V bottle-shaped battery. The new seatpost battery should only have an autonomy of 7 miles of steep hills (40%) between each daily charge. What are your recommendations? Happy day! Fred

3. Lastly, I assume if the BMS & battery were able to produce the 50A X 24V watts of 1200W that my electric motor would only ever use the 500W it is rated for? As in the E bikes controller would only draw around 500W?

When you buy a Hobby King pack, it will have a number of these large cell LiPo’s strung together like this 6 cell in-series (6S) pack. The big downsides of this pack is that it will only last you in best case maybe 300 charges and it is volatile, and susceptible to possible fire if not well managed and cared for.  When using cobalt-based LiPo, it is best to use some kind of BMS, and also you should charge it in a safe location.

Regarding the soldering of cells: generally it is not recommended as no matter how you do it, a soldering iron will still transfer more heat than a spot welder. That being said, I have seen packs that have been welded using both solid or braided copper wire. I’ve also seen someone use copper wick soldered to the cells terminals. It’s impossible to know exactly how much of an effect that the heat transfer had on the cells but if you don’t mind taking a risk of some level of deterioration of the cells performance, then it technically is possible to solder the cells together.

I’m mostly kidding, but if you use cells that are rated for more current than you’re trying to pull from them, you’ll create a lot less waste heat and both options will be perfectly fine and healthy for the battery.

Used PL-350 electric bike kit, The battery does not charge. Charger is fine but only shows a red light. It sat dead for about a year. Then the controller showed about 80% after charging. Everything wo…

The high C-rate is not the only reason LiPo is adored by the high performance crowd, the addition of Cobalt to the cathode meant that more power would fit in a smaller package. This was driven by the boom in Radio-Controlled (RC) models in the late 1990’s (RC airplanes, cars, helicopters, etc). When that market suddenly expanded, an Australian enthusiast started a company to supply RC parts from factories in China. Hobby King.com was born. Last year, due to popular demand, HK has opened warehouses in The USA and in Germany (edit: even more countries have HK warehouses now).

Linear packing, on the other hand, will result in a narrower pack that ends up a bit longer than offset packing. Some people say offset packing is more efficient because you can fit more cells in a smaller area by taking advantage of the space between cells. However, offset packing creates wasted space on the ends of parallel group rows where gaps form between the edge of the pack and the ‘shorter’ rows. The larger the battery pack, the less wasted space is taken up compared to the overall pack size, but the difference is negligible for most packs. For my battery, I decided to go with offset packing to make the pack shorter and fit easier into a small triangle bag.

Its low C-rate of 1C means you need a large pack if you want higher amps. Justin at ebikes.ca was an early adopter of LiMn for his E-bikes because his customers wanted a trouble-free product that wasn’t fussy and lasted a long time. Makita cordless tools use LiMn, as do many laptop computers. Last year Zero E-motorcycles were using LiMnO2, but this year they moved up to NMC (found listed below). [edit: Due to customer desires and safety concerns, LiMn has been improved and now in 2014, there are high current LiMn]

Wear safety goggles. Seriously. Don’t skip this one. During the process of spot welding it is not at all uncommon for sparks to fly. Skip the safety glasses and head for chemistry lab style goggles if you have them – you’ll want the wrap around protection when the sparks start bouncing. You’ve only got two eyes; protect them. I’d rather lose an arm than an eye. Oh, speaking of arms, I’d recommend long sleeves. Those sparks hurt when they come to rest on your wrists and forearms.

I hope not to have to replace the whole battery pack and wondering if it can be salvaged by replacing the just the dead cells and burnt connectors, or do you think the damage is too extensive to be worth repairing it?

LiMn/LiMnO2-Lithium Manganese Oxide. Adding manganese to the cathode made this chemistry more stable and less sensitive to individual cell balancing issues. If you were using LiFePO4, and one cell began losing its amp-hour capacity, the rest of the pack would get dragged down to the weakest cells level. Demanding high amps with one weak cell in the pack would cause the entire pack to wear out much earlier than it should have.  With LiMn, the packs just seems to stay in balance, with all the individual cells aging equally.

Actually I have ran into a problem – a few days ago I was riding it up a hill on a hot day when the power cut off and it wouldn’t start again. When I tried to charge it, the light on the charger just flickered from green to orange. I took out the battery and found that one of the cells had corroded from what looks like overheating. I think that the battery pack failure was most likely caused by too much of a load applied to the battery pack.

I use white 2mm thick craft foam and cut out a shape slightly larger than my pack. I wrap it up and seal it with electrical tape. It doesn’t have to be pretty, it just has to cover the pack. Your next step will hide the foam from view.

Some of the NMC sellers are advertising their chemistry as 5C, but real-world use by E-bike builders has them calling NMC a solid reliable 3C chemistry, which can provide a continuous 30A from an affordable and compact 10-Ah battery (temporary peak amp-draws can be higher, as it is with any of these chemistries). This may sound only as good as the most recent LiFePO4, but NMC is smaller, and is not as fussy about keeping the individual cells balanced.

Your battery pack size is based on voltage and amp-hours. The higher the voltage and the higher the amp hours of your battery, the more range your battery will give you. A 48V 10-Ah pack gives you 480 watt hour (48 X 10). This gives you an easy way to determine exactly how much battery you are buying. The wattage of a battery is the only accurate determinant to judge what range your finished ebike will have.

For this tutorial, I’ll be using the green Panasonic 18650PF cells shown above. Lately though I’ve been using 18650GA cells like these, which are a little bit more energy dense, meaning more battery in less space.

Alternately, you can separate the batteries and charge each with its own charger, but then you have some small risk of reconnected the batteries when one is charged and the other is flat, if for some reason one of the batteries didn’t get charged up properly. We usually recommend leaving the packs parallel connected at all times.

Next, regarding your question of paralleling the batteries. Yes, you can parallel them, and you can do it even before connecting to the controller. The biggest safety issue (and damage issue) though is to always be sure they are at the exact same voltage when you connect the two batteries in parallel. The easiest way to do this is only to connect them in parallel when you’re sure they are both fully charged.

3. i saw 18650 and 26650 li ion batteries which are more powerful such as 6000 – 8000 mah. i think they are fake??? i need 48v 10ah or 20ah minimum i guess as a pack ??? your advices are important. thanks for all…

This is the old technology for e-bikes that is heavy as bricks and does not have longevity. Lead acid will double the weight of your electric bike. Unless you have to because of money restraints, batteries for e bikes advise to steer way clear of lead acid batteries.  Your bike will have a completely different feel and range if you spend the money on one of the new lithium technologies.

Remember, if a battery with a certain chemistry can “survive” at 2C, it may actually last much longer if it is sized so that the amp-draw from the controller/motor is only 1C. If it can actually be run at 2C, but it dies in a month with daily use…and yet if sized to run at 1C it lasts a year? Legally the manufacturer is not lying by calling it a 2C battery. There is nothing wrong with that, but…we here want E-bike customers to be aware of the real-world results so they can make an informed decision, and avoid the disappointment that could turn off a lot of potential E-bikers to a wonderful sport and hobby.

“replacement battery for electric scooter +electric bike battery”

A recent quote from ES member SamTexas on claimed max C-rates: “…I have in front of me Samsung’s own Nickel (Manganese) 18650 cells….I have tested these cells at 3C continuous and they do deliver full capacity at that rate. Push it to 5C and they become hot and capacity is greatly reduced…“

One question regarding the specific battery BMS you used in this build: It uses a different wire for charging vs discharging the battery. Does this mean that the regenerative braking feature cannot be used for this battery?

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I purchased the 220v welder, which obviously was intended to run on non-US half of a phase 220v, Of course we have full single phase 220v, so could you supply me with a hint on how to wire the unit for US 220 v.

Next, plan out your cell configuration on your computer or even with a pencil and paper. This will help ensure you are laying out your pack correctly and show you the final dimensions of the pack. In my top-down drawing below I’ve designated the positive end of the cells in red and the negative end of the cells in white.

That’s exactly correct. You’d start by welding 10 parallel groups of 4 cells each, then you’d connect those 10 parallel groups in series to make one rectangular battery. I’ve done many 10s4p packs just like that for 36V 10ah ebike batteries.

You can certainly use a second 4.4AH battery in parallel to double your range, but you’ll want to make sure the batteries are at the same state of charge when you connect them in parallel, or use a diode in between them, to keep one battery from discharging the other if the charge states are unequal.

I am planning on making a 6S2P LifePO4 pack that has a voltage of 19.2V. I have a 6 cell BMS that does balancing (and that is intended to work with 6 LifePO4 cells). I need some help selecting a charger to charge this pack, however, particularly regarding the charger’s voltage specification.

But having read through the document mostly, not completely, I simply stopped reading further due to incorrect usage of words and many bad spellings, some of which would not be caught by a spell checker – “table” for “stable” for example.

Lastly, regarding the spot welder. I actually prefer to use the kind like you said, with the two arms that lift up and provide equal pressure at each weld. The kind with two long welding cables like this welder has both options which is nice, especially for if you need to reach to the middle of a pack to make a repair or if you missed a weld. I mostly use the short rigid arms though and just weld one row at a time before adding more cells – that way I can reach all the cells with the short arms.

“The secret of NMC lies in combining nickel and manganese. An analogy of this is table salt, in which the main ingredients of sodium and chloride are toxic on their own but mixing them serves as seasoning salt and food preserver. Nickel is known for its high specific energy but low stability; manganese has the benefit of forming a spinel structure to achieve very low internal resistance batteries for motor scooters offers a low specific energy.

Nickel Metal Hydride batteries are about 20% lighter and 30% less voluminous than a NiCd pack of the same capacity. They have similar discharge and charge characteristics, but because of the higher energy density they are available in higher capacities than NiCd packs. Because NiMH is safe for disposal in the landfill while Nickle Cadmium is not, the metal hydride has almost completely replaced cadmium in most consumer batteries.

I would advise against connecting one battery to the other’s charging port. That charging port, as you correctly stated, is wired to a charging circuit on the BMS which is usually meant to take 5A max, sometimes less, whereas the discharging side of the BMS usually puts out at least 15A, sometimes much more. You can easily fry your BMS by connecting a second battery to its charge port.

Your battery pack size is based on voltage and amp-hours. The higher the voltage and the higher the amp hours of your battery, the more range your battery will give you. A 48V 10-Ah pack gives you 480 watt hour (48 X 10). This gives you an easy way to determine exactly how much battery you are buying. The wattage of a battery is the only accurate determinant to judge what range your finished ebike will have.

When it comes to the nickel strip you’ll be using to connect the 18650 batteries together, you will have two options: nickel-plated steel strips and pure nickel strips. Go for the pure nickel. It costs a little bit more than nickel plated steel but it has much lower resistance. That will translate into less wasted heat, more range from your battery, and a longer useful battery lifetime due to less heat damage to the cells.

“scooters batteries battery electric bicycle”

Continue down the row of cells placing a weld on each cell. Then go back and do another set of welds on each cell. I like to do 2-3 welds (4-6 weld points) per cell. Any less and the weld isn’t as secure; any more and you’re just unnecessarily heating the cell. More and more welds won’t increase the current carrying ability of the nickel strip very much. The actual weld point isn’t the only place where current flows from the cell to the strip. A flat piece of nickel will be touching the whole surface of the cell cap, not just at the points of the weld. So 6 weld points is plenty to ensure good contact and connection.

I use my welders on 220V, though 110V versions are available. If you have access to 220V in your home (many 110V countries have 220V lines for clothes dryers and other high power appliances) then I’d recommend sticking with 220V. In my experience the 110V models seem to have more problems than their 220V brothers. Your mileage may vary.

If you are using 2.5AH cells then yes, it will be 5AH with a 2p configuration. If you use cells with higher capacity, like Sanyo GA http://electricbikebatterys.com that are 3.5AH, then you’ll have a 7AH pack with only 2p. Make sure your cells can handle the current that your electric scooter (and namely the controller) will try to draw from it.

This is what I refer to “small cells”, the 18650 (cordless tool) type cells which need to be spot-welded or soldered together to form a large pack. The big advantage of these cells is they offer better cooling because of the nature of their shape to the LiPo soft pouches, and therefore have the capacity to last longer.

One of the easiest ways to increase the current handling capability and range is to put two or more batteries in parallel. In general, with lithium batteries of the same nominal voltage, this is no problem. It is perfectly fine to mix old and new lithium batteries in parallel, or even batteries from different manufacturers and with different capacities, so long as they are the same voltage. We stock a parallel battery joining cable to facilitate connecting packs this way. 

Where things can get a bit dicey is in charging batteries that are parallel connected. If you leave the batteries in parallel while charging, then the charger current will get shared between the batteries and you can be sure that they are always at the same charge level. However, that does mean one of the batteries will be getting charged through the discharge port, and depending on the specific BMS circuit it may not have overcharge protection on the discharge wires.

When you wire in series you only increase voltage, not amp hours. So you’d have a 48V 5AH pack in that setup. Not enough range, in my opinion. If you want my advice, the single best upgrade you can do to that bike is to replace the battery and controller for 48V units. It will give you about 30% more speed and power. You won’t need to drill vent holes or anything, that motor can handle 48V as long as you aren’t riding up any 5 mile long uphills with a 250 lb rider. Shorter uphills and flat land will be fine all day long.

A recent quote from ES member SamTexas on claimed max C-rates: “…I have in front of me Samsung’s own Nickel (Manganese) 18650 cells….I have tested these cells at 3C continuous and they do deliver full capacity at that rate. Push it to 5C and they become hot and capacity is greatly reduced…“

Next, plan out your cell configuration on your computer or even with a pencil and paper. This will help ensure you are laying out your pack correctly and show you the final dimensions of the pack. In my top-down drawing below I’ve designated the positive end of the cells in red and the negative end of the cells in white.

I want to build a 36v ebike battery for my 36v 500w motor. What battery you recommend for me which gives the enough current and capacity. My plane is to build a battery with 40 cells 10 in s and 4 in p,

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100~240VAC Universal AC input Full range LiFePO4/Lithium Ion/Lead Acid 4000W Battery Charger Two S2500 model in parallel. Power:4000Watts; Protection function: / Overload / Over voltage / Over temperature / Over current / Reverse polarity / Power off or trickle after finished charging; 2 years warranty

There are six rechargeable battery types that have seen regular use in electric bicycle battery packs. We have never been involved with lead acid batteries, and discontinued dealing NiCad and NiMH packs in 2010.

Introduce Yukon Trail 2018 new model Xpedition Features: 350w motor Battery: Samsung lithium battery (light weight 5 lbs with case) Speed/Mileage: up to 20MPH, up to 28 miles per full charge (varies b…

I’d recommend going with a cell that can output 10A, giving you 40A continuous power rating. You’ll use less than that, meaning the cells will be happier (and cooler). Something like the Sanyo 18650GA or LG MJ1 would give you good power and capacity (both are around 3,400 mAH per cell).

Rated Capacity: 10Ah. Recommended to be used with 36V 250W electric bicycle motor. 36V 750W 20″ Front Tire e-Bike. Charge Current: 2A. Model: Bottle Type. 1 Year manufacturer warranty for CHARGER. Use…

When choosing a battery for your bike, not only is the weight important but the volume is also important. You want your pack as small as possible so its easy to stow and easy to hide. So therefore you should consider you battery’s volume, not just its weight. For sure you need to go with a lithium chemistry and not an old school heavy and large Sealed Lead Acid (SLA) or Nickel-Metal Hydride (NiMH) chemistry.

And if you don’t want to purchase my book (or you already have a lot of ebike knowledge), you can still support this site by simply clicking on this link before you shop on Aliexpress. Basically, that’s an affiliate link that shows Aliexpress that you came to them via my site. It doesn’t effect you at all, but if you make a purchase, this site will get a small percentage of the profit that Aliexpress makes. It’s a simple way to help support this site so I can pay the hosting and keep providing more free info (and to keep this site free of annoying ads). I have some of those affiliate links on a limited number of articles on my site. When I personally buy and test products that I find to be a combination of great quality and great prices, like these batteries, for example, I like to share them through those affiliate links. Again, it costs you nothing, but it allows me to keep cranking out more info and content for you guys!

I’m sorry but I’m not certain. Here in Israel we are on 50hz so I haven’t tried that model on 60hz. I do however have some friends in the US that have that model on 60hz. They have been happy with it, but I haven’t used it myself so I can’t say how it compares to my experience.

A better and simpler solution would be, as you said, to carry a second battery and just swap the connector from the old battery to the new one when the old battery is depleted. There are a few types of bottle batteries out there, I recommend googling “bottle battery” if you haven’t yet, you’ll likely find a few options. I don’t know if this is the same model as yours, but some common styles similar to your description can be found here and here.

The 48V, 8AH lithium battery of this ebike is removable. Material: Aluminium alloy frame. E-bike & Assisted bicycle, you can choose the E-bike to enjoy a long time travel, and also exercise. Combining…

I have found this BMS which is cheap (necessary for my project) and it is shipped from the UK. Because it is so cheap do you think that it may not be balancing? http://www.ebay.co.uk/itm/400984825723?euid=0502c7e2b2c744ec8857879d65d46e08&cp=1

To determine how much power you need, you’ll need to determine the voltage you want and the capacity you need to supply that power (voltage times current). Read this article to learn more about calculating your ebike’s power: http://www.ebikeschool.com/myth-ebike-wattage/

LiFePO4-Lithium Iron Phosphate. This was the first lithium chemistry that really took off for use in cordless drills and laptop computers. Mass production brought the prices down, and E-bikers began buying cordless drill packs and gutting them for the cylindrical cells, so they could be re-configured from the stock 18V up to 48V (or more). The common low C-rate was around 1C, so builders began making packs for high voltage to get better performance without stressing the pack by trying to pull high amps. LiFePO4 requires a sophisticated Battery-Management-System (BMS) to stay healthy.

If none of our own battery offerings meet your needs, we can also highly recommend the knowledgeable folks at Batteryspace.com and EM3EV as alternate suppliers of lithium battery packs in a wide range of capacities, form factors, and voltages. 

I am however encountering problems in finding a BMS for my pack which will be 2 or 3 P and 7 S to replace 24V 6 AH in frame battery pack. Can you please enlighten me as to where I can access a suitable BMS. Thanks for any help. K.

I am planning to build a 14s7p pack with the GA batteries for a little over 1 KW of power. I went to the BesTechPower site and their are several 14s BMS’s there. Which one would you recommend for a battery this size? Can you send/post a link to the specific on on their site? thank you.

This had led me to believe that if there is too much load being exerted on the bike (i.e. the current being drawn from the battery is too high) then either the BMS or the controller trips and cuts out. However I am reluctant to believe that the BMS is causing the trouble as it has a 40A rating on it (this link shows the exact BMS) http://www.aliexpress.com/item/Electric-motor-car-13S-48V-40A-BMS-lithium-ion-battery-BMS-Used-for-48V-20Ah-30Ah/32484213150.html?spm=2114.13010608.0.62.evx6sX .

Combining the metals brings out the best in each. NMC is the battery of choice for power tools and powertrains for vehicles. The cathode combination of one-third nickel, one-third manganese and one-third cobalt offers a unique blend that also lowers raw material cost due to reduced cobalt content“

“48 volt scooter battery e bike lithium ion battery”

NiMH-Nickel Metal Hydride. This was the battery of choice for military application and the first-gen Prius hybrid car. Very reliable and stable, with a long cycle life. It has a high nickel content, so its expensive now (but the nickel can be re-cycled). With a low C-rate, you need a very big battery to draw high peak amps. Perhaps not a problem on a car with its huge battery pack, but on a bicycle, the smaller pack restricts the user to low amp-draw performance.

Charge current depends on the cells. Most cells can take at least 500mA, some considerably more. It’s hard to know what cells you’re using. Assuming they are 18650pf Panasonic cells like I used here, 1A per cell would be fine, giving you a charge rate of 3A. They can actually take more than that, but there’s no reason to push them too hard if you don’t have to.

hello sir. nice guide FOR battery pack li-ion… i will try an electric bike kit for my 26″ MTB. and buy 1000w hub motor kit. i can solve my battery problem (expensive you know) with li ion pack. i have some questions,

Finally, have you used the type of spot welder shown with hand held probes? Can see the benefit of greater reach, but do you know if this gives as neat a result (my spot welder there is a very firm press up to activate, hence the discharge only occurs when the tips of the welder are pressing the strip firmly against the top of the cell so i assume ensuring a tight weld)

Lipo batteries are currently the “hottest” battery choice for electric bike enthusiasts. LiPo batteries are the most power-dense type of  battery available to electric bike riders today. The problem is that LiPo battery packs for e-bikes are hard to find, especially one with high output if you are building a racing bike for riding off road.

I’m mostly familiar with BesTech’s 72V BMS’s and haven’t used a 52V BMS from them, so I can’t give you a recommendation on a specific 52V (14s) BMS from them, sorry. I have used this 14s BMS twice and it’s worked great for me on two 14s7p packs I made with Samsung 26F cells.

1C charging is too high for most Li-ion. It’s too much to ask for right now, to be able to charge an entire pack in one hour. It can be done, but it’s not healthy for the cells. Aim for 0.5C at the most. I usually don’t go past 0.3C on charging.

For people who are new to the hobby, ready-made lithium packs are the way to go. Several manufacturers offer ready to go Lithium packs with a built in Battery Management System (BMS) at affordable prices.

Regarding your first question: as long as your BMS has a balancing function (most do) then you do NOT need a charger that does balancing, and in fact you should not use one. The BMS takes care of all the balancing, so all you need is a simple ebike charger. What is important though is that it is a CC-CV (constant current, constant voltage) charger. Most ebike chargers are, but just check to make sure it says that somewhere in the description, or ask the vendor if you can’t find it. The CC-CV part means that the charger will supply a constant current first, bringing the battery voltage up slowly until it reaches the full voltage (54.6V for your 13S battery). Then it switches to CV mode and holds a constant voltage while it gradually backs the current down to zero, which is the ‘finishing’ part of the charge.

Lead acid batteries are the least expensive and heaviest battery option. They have a short cycle life if used regularly in deep discharge applications. For electric bikes, the most common setups use 12V bricks of either 7Ah or the larger 12Ah capacities, series connected to form 36V or 48V packs. Because of the Peukert effect, the 7Ah gel cell usually delivers about 4 amp-hours of actual capacity, while the 12Ah lead acid packs will deliver approximately 8 amp-hours. So keep this in mind when comparing a lead acid pack to one of the NiCd, NiMH, or lithium replacements. We do not offer lead acid batteries or chargers, but they are not hard to find.

Power ratings of E-bike kits and the C-rates of batteries for sale are ALL highly suspect. The endless-sphere authority on batteries and their C-rates is Doctor Bass. He has nothing to gain from misrepresenting any chemistry or battery manufacturer. I must admit I am annoyed if a new battery is claimed to be a 5C chemistry, but testing shows it to survive better at 3C, however…a misrepresented battery that is a true 3C is still a good thing.

LiMn was by far the most common chemistry in cheap (and expensive!) built up electric bikes for a long time. It’s a cheap, light, safe chemistry. The problem is low C, but much more importantly short life. And not just a short number of cycles but a short shelf life as well. Losing 20% capacity a year even if you don’t use the battery much leads to a lot of expense and warranty claims. LiNiCoMn has the same low cycle life, light and cheap characteristics, but it seems to have a longer shelf life and a slightly higher C.

Ideally, I would buy a battery with the same type of connection and just carry the spare one unconnected and swap them over but I don’t seem to be able to find the type of battery case for sale anywhere. It’s a quick release bottle type battery that has two sprung terminals about half inch in diameter that contact with two large terminals on what I think must be the motor controller integrated into the bottom of the bottle mounting bracket.

The following is an overview of the ShippingPass Pilot subscription service. You should review the Terms & Conditions for a more detailed description as well as service limitations prior to signing up for ShippingPass.

There are two main levels of spot welders currently available: hobby level and professional. A good hobby model should run about $200, while a good professional one can easily be ten times that price. I’ve never had a professional welder because I just can’t justify the cost, but I do own three different hobby models and have played around with many more. Their quality is very hit or miss, even on identical models from the same seller. Unfortunately the lemon ratio is quite high, meaning you could fork over a couple hundred bucks for a machine that just won’t work right (like my first welder!). Again, this is a good reason to use a site with buyer protection like Aliexpress.com.

2. I highly recommend using a BMS in both Li-ion and LiFePO4 batteries. As a Li-ion vs LiFePO4 question, one isn’t necessarily better than the other. Li-ion will be cheaper and probably more powerful, but LiFePO4 is going to last years longer, so it’s all about what you want in your battery.

Here at Grin we’ve been dealing with ebike batteries for a very long time during which we’ve offered over 100 variants of NiCad, NiMH, LiFePO4, LiPo, and Lithium-Ion packs in all kinds of voltages, geometries, and capacities. It’s been a love/hate relationship over those years, but the more recent mass production of 18650 lithium cells for high power consumer goods like power tools has shifted things to the love side, with ebike batteries that are cheaper, lighter, and with far longer life span than we could have ever wished for in the past. We’re happy to stock both frame mount and rear rack mounted batteries from 98 watt-hours to 1100 watt-hours in size to suite the needs of most electric bicycle conversions. 

 An electric bike battery is a power storage medium for use with electric bikes and electric trikes. An electric bike battery can be a lead battery, or a lithium type battery similar to those in laptops, or cordless power tools. A lead electric bike battery is usually of the type called SLA, which stands for sealed lead acid. A lithium electric bike battery may be one of several types. The most commonly used lithium electric bike battery types today are Lithium Iron Phosphate (LiFePO4 or Life) or Lithium Nickel Manganese Cobalt Oxide (LiNiMnCoO2 or NMC). The E-Bikekit lithium electric bike battery is a Lithium Nickel Manganese Cobalt Oxide type battery. Considering the size and weight difference between LFP and Li-NMC, all lithium packs are Lithium-Ion, but not all are the same energy density – LiFePO-4 batteries are larger and heavier than Li-NMC.

The bike was more than happy to run and pull me along as long as the throttle was kept very low (<~30%) but as soon the throttle was turned more or I came across a slight gradient uphill the system would cut off (no lights or power). I then have to plug the battery into my charger to 'reset' it before I can then plug it back into my bike and make it work again. I have to keep the throttle low whilst I batteries for e bikes riding on the bike before it cuts out but if the wheel is spinning freely in the air then I can max out the throttle and make the motor run at full speed.

22f cells are quite low capacity and not very strong. They will work for an ebike (and are about the cheapest good quality cells out there) but they aren’t optimal. You’ll end up with a larger and heavier pack as compared to more energy dense cells like Panasonic 18650pf or Sanyo 18650ga cells.

hello. I have a KTM bike-trail’s 2013 model. I have problems with the battery. I had the bike wheel and I bought one original ktm 26V from the company. defect occurs so: I put the plug on the charger to charge the battery and flashing green LED lights and red and it is immediately interrupted – interrupted flashing red and the buzzer sounds and noises that can fix … ? Please help me if you know how. sorry for my English but I used google translator

40% grade hills? That’s huge! You’ll definitely want a cell that can perform at high current since you’ll be pulling peak power from those cells to get up those big hills. Something like the Samsung 25R would be a good choice for this application.

Sorry if this has been asked already but there are a ton of comments to wade through. Ten individual 18650 cells in series at a nominal voltage of 3.6 Volts would give me 36 volts. Assuming they are 2500 mAh a piece, then if I put 4 of these 10 cell in series packs together in parallel I would have a 10 Amp Hour battery correct? The same applies if I were to wire a pack together with 10 “4p” cells together in series. I’m trying to determine what the benefit of 10s4p over I guess what would be “4s10p”.

I’m planning on building a 10S12P pack for usage on a custom DPV (Diver Propulsion Vehicle). For packaging purposes, it would be best for me to split the battery pack in several battery modules instead of a single block of cells.

“electric bike batteries lithium _bike batteries”

It is possible to do it that way, however there are some compelling reasons not to. 1) By first joining all the series cells you would end up with multiple high voltage groups, which means both the chance and consequences of an accident are greater. When you’re working with lots of exposed batteries with nickel conductors and metal tools flying around, the last thing you want is more high voltage possibilities for shorts. 2) Doing series cells first would be come unwieldy, physically. A series group is only connected at either the top or bottom of alternating cells. Without having multiple cells side by side to add stability, a long chain of single cells will need either a pile of glue or some type of physical holder to support the chain. and 3) most battery spot welders can only reach about 2 cells deep into a pack, meaning you’d have to either add very short nickel strips to each series group connecting only two groups (which means twice the welding and twice the cell damaging heat) or have long uncontrolled nickel strips hanging off the sides, again risking shorting.

To determine how much power you need, you’ll need to determine the voltage you want and the capacity you need to supply that power (voltage times current). Read this article to learn more about calculating your ebike’s power: http://www.ebikeschool.com/myth-ebike-wattage/

The best method is to use a trusted vendor. They interact with the cell providers and are the best way to confirm whether cells are fake or not. It can be incredibly difficult to tell whether a cell is fake or not just by picking it up from the table. There are some giveaways like different printing on the wrapper, slightly different color, different stamp, different weight or different shell design, but all of those can be mimicked. That’s why I use only a handful of vendors that I’ve worked with continuously and who I know have always given me good quality cells. I had to go through some low quality ones until I found the sources I buy from now.

I then took my second sense wire (or your third sense wire if you have one more sense wires than parallel groups) and soldered it to the positive terminal of the second parallel group. Again, note that I’m soldering this wire to the nickel in between cells to avoid heating any cell directly.

Also changing the fuse to a higher one could cause the wires to start a fire and the whole house would burn down if the wires are not thick enough. Also in sweden a fuse gets bigger as they are rated higher so you can fit a 20A fuse in a 10A slot, for safety.

There are two main levels of spot welders currently available: hobby level and professional. A good hobby model should run about $200, while a good professional one can easily be ten times that price. I’ve never had a professional welder because I just can’t justify the cost, but I do own three different hobby models and have played around with many more. Their quality is very hit or miss, even on identical models from the same seller. Unfortunately the lemon ratio is quite high, meaning you could fork over a couple hundred bucks for a machine that just won’t work right (like my first welder!). Again, this is a good reason to use a site with buyer protection like Aliexpress.com.

There are formulas out there for calculating the exact size of heat shrink you need but I often find them overly complicated. Here’s how I figure out what size I need: take the height and width of the pack and add them together, and remember that number. The size of heat shrink you need when measured by the flat width (half the circumference) is between that number you found and twice that number (or ideally between slightly more than that number to slightly less than twice that number).

Battery manufacturers are continuing to research for developments in dozens of battery chemistries, and a couple of years ago, a big improvement to LiPo/LiCo chemistries began to be produced. A high-Cobalt cathode (LiCo) provides very good power density, but how can we make it more stable and reliable? Here’s a quote from batteryuniversity.com

You can use any connectors you like. I’m a big fan of Anderson PowerPole connectors for the discharge leads. I used this other connector that I had in my parts bin for the discharge wires. I’m not sure what that type of connector is called, but if someone wants to let me know in the comments section then that’d be great!

Lithium batteries are also small enough to allow you to place your batteries pretty much anywhere on your bike. This is especially true for people who want to assemble their own pack or use heat shrink wrapped lithium batteries instead of hard case lithium batteries with prefabricated bicycle frame mounts. This can help spread the weight around or hide the batteries to make a stealthier bike.

I hope not to have to replace the whole battery pack and wondering if it can be salvaged by replacing the just the dead cells and burnt connectors, or do you think the damage is too extensive to be worth repairing it?

Good question. The answer comes down to the difference between “nominal voltage” and “actual voltage”. LiFePO4 cells are nominally called 3.2V cells, because this is their voltage in the middle of their discharge curve, at about 50% discharge. They actually charger to a higher voltage though, about 3.7V per cell. That means that you need a charger that has an output voltage of 3.7V x 6 cells = 22.2V DC. This is going to be a bit harder to find because most LiFePO4 packs come in multiples of 4 cells, (4, 8, 12, 16 cells, etc) so finding a charger for a 6S pack might take some searching. This charger is a good quality one meant for 8 cells (output voltage of 29.2V DC) but if you put a note in the purchase order, the seller can adjust the output for 6 LiFePO4 cells (22.2V DC). http://www.aliexpress.com/store/product/aluminum-shell-24V-29-2V-3Amper-Lifepo4-battery-charger-high-quality-charger-for-8S-lifepo4-battery/1680408_32274890691.html

Small hard-cased A123 cells (about the size of a “C” battery) have been salvaged out of power drill packs, car battery packs etc, and have made it into the hands of e-bike DIYers who solder them together in series and in parallel to construct a pack big enough and powerful enough to power an e-bike.

Landcrossers Hailong E-Bike Battery. Case Material:ABS Aluminium alloy. Fuse Installation position:Inside on the PCB. Fuse Diameter(mm):5. Fuse Length(mm):30. Fuse Current: 30A. 1 x Lithium Battery wi…

Whether you’re shopping for a turn-key commercially available electric bike, or trying to find or build a good battery for an e-bike conversion, being able to find the right battery for an electric bike is a difficult task.  The right battery pack is the most difficult part of the e-bike equation. Keep in mind that even if you’re buying a turn-key electric bike, the lithium battery is more than likely the most expensive component in it, and…not all lithium batteries are created equal, so you should know what you are getting before you buy the ebike.

I am new to the ofrum and to the ebike world so I would like to seek some advice please. I have recently bought a sondors fat bike to the UK and want to make some tweaks, I would like to upgrade the battery on a budget, I was thinking of 4 x 12v 5ah lead acid batteries in series, would this give me 48v 20ah or have I got this totally wrong? I want to replace the stock contoller for a 48v 25amp one, would this suffice? lastly it comes with a stock 350w bafang motor, if I make the battery and controller upgrades will the motor handle the increase in wattage? could I drill venting holes in the case cover to expell some heat? Your thoughts and advice would be most welcome,

If you don’t find that, there’s still a chance that it’s the problem, and that the cells simply rose up to a higher voltage and matched the others again once the load disappeared. But it also may be that the load is too high for the BMS. Do you have a cycle analyst? You could slowly increase the throttle and watch how much current you are drawing until the point of cutoff. If it’s well below 40A then you’ll know it’s not a high current cutoff.

LiFePO4/Lithium Ion/Lead Acid 120W Battery EBike Charger. 12V6A,24V3A,36V2.5A,48V2A;  Li-Ion Battery Charge Voltage = 4.2V x the number of cells in series; LiFePO4 Battery Charge Voltage = 3.55V x the number of cells in series.

Nickel Metal Hydride batteries are about 20% lighter and 30% less voluminous than a NiCd pack of the same capacity. They have similar discharge and charge characteristics, but because of the higher energy density they are available in higher capacities than NiCd packs. Because NiMH is safe for disposal in the landfill while Nickle Cadmium is not, the metal hydride has almost completely replaced cadmium in most consumer batteries.

If you are using 2.5AH cells then yes, it will be 5AH with a 2p configuration. If you use cells with higher capacity, like Sanyo GA cells that are 3.5AH, then you’ll have a 7AH pack with only 2p. Make sure your cells can handle the current that your electric scooter (and namely the controller) will try to draw from it.

I am however encountering problems in finding a BMS for my pack which will be 2 or 3 P and 7 S to replace 24V 6 AH in frame battery pack. Can you please enlighten me as to where I can access a suitable BMS. Thanks for any help. K.

I have now come to the conclusion however that i want a pack that is 48V and capable of running a 1000w motor for atleast an hour. I live in a hilly area, i use a downhill bike (heavy) and im not the smallest guy. Im feeling a bit insecure about putting too many cells in parallel. Through the years i’ve read that the consesus is that more than 4 cells in parallel is a risk. Since a 13S4P pack is about 12Ah (with good batteries) i was wondering if you had any input on how i should move on?

I did not intend for the timeline to reflect anything other than what I recall seeing as E-bike battery packs. Some chemistries have been around a long time before they were used by a significant number of E-bikers.

Nissan, Imara, Microvast, and Zero E-motorcycles are now using NMC after extensive testing. Let’s take a quick run down memory lane to show how battery chemistry has evolved in just a few short decades. The following is not the order of their invention, just what my foggy memory recalls as seeing them used in E-bike battery packs.

Manufacturers usually rate their cells’ capacity at very low discharge rates, sometimes just 0.1c, where the cells perform at their maximum. So don’t be surprised if you’re only getting 95% or so of the advertised capacity of your cells during real world discharges. That’s to be expected. Also, your capacity is likely to go up a bit after the first few charge and discharge cycles as the cells get broken in and balance to one another.

For a heavy trailer, I’d add a second brushed motor to the cart, whether the bike has a motor or not. You’d only need 24V, and here’s a discussion about powered trailers. The most important thing for going over sand is to have the fattest tires http://electricbikeframes.com can fit onto the trailer.

If you don’t have an actual heat gun, you can use a strong hair dryer. Not all hair dryers will work, but my wife’s 2000 watt model is great. I own a real heat gun but actually prefer to use her hair dryer because it has finer controls and a wider output.  Just don’t go mess up your wife’s hair dryer!

I’m not familiar with this copper serial connection you’re talking about. I guess you mean to reinforce the series connections to handle more current? As long as you are using enough strips of nickel (and ensuring that it’s pure nickel and not nickel coated steel) then you shouldn’t need copper reinforcements. I try to use at least 1 strip of nickel for every 5A my battery will carry. So if I’m looking for a 20A max load, I’d use 4 strips of nickel in each series connection. That’s easy to do if each cell in a parallel group of 4 cells is connected to the next group by one strip each.

A High-performance Motor acheives a top speed of 20-30km/h with a range of 20km means your ebike commute just got easier. 36V 8AH Lithium-Ion Battery. Motor: 36V 250W brushless. Rang: 18-25km(36v 6ah)…

3. Lastly, I assume if the BMS & battery were able to produce the 50A X 24V watts of 1200W that my electric motor would only ever use the 500W it is rated for? As in the E bikes controller would only draw around 500W?

“diy electric bicycle -emoto electric bike battery”

The only thing left to do at this point is to add the connectors, unless you did that before you soldered the wires on, which I actually recommend doing. But of course I didn’t do that, so I added them at this step, being careful not to short them by connecting only one wire at a time.

Thank you for the article! I am currently making a battery for an electronic skateboard, so I need the layout to be as thin as possible to allow ample room underneath the deck. Currently, I have 6 packs of 3 cells welded in parallel, and would eventually like to create a battery which is 9 cells long, 1 wide, and 2 high, for 18 in total (the two packs of nine would then be welded in series). I am wondering if I could be able to make 2 battery packs by welding 3 of my current 3 cell packs together in parallel to make a long, yet skinny pack, and then welding both packs of nine in series using the alternating system. Essentially, I would be creating a pack that would look like 3 of the ones you show above when making your first series connection. Let me know what you think, and thank you!

36V 10ah Lithium battery (Included with the battery is the charger and mounting Bracket). Standard 26 in Front Wheel 500w brushless motor hub (works with V-brake or disc brakes). Pedal Assistance syst…

I have come to the conclusion that a 48v battery would probabky be sufficent for my needs. I need to ride continuously for at least 7-8 hours–but prefer up to 10 hours– at 15-20mph everyday. Although I also need a top speed of 30mph, at times. If my math is right, in order to accomplish this I need to build at least a 14s8p battery. After running these specs through a simulator I found that the power starts to drop at about 1150 watts and 20mph.

I am currently building my own 36v battery and now using some of the ideas you have put here. but I am wondering what is going to be the best charger for charging the battery?? As I am doing on the cheap, I am utilising a 12v 6A charger which I previously had. My plan was to couple with a 12v to 36v step up DC transformer but then realised that this may not be enough to charge the battery fully. This is because the full charge voltage on the battery is actually 41v which would be higher than the step up transformer. The next option is a 48v charger which would be too high.. Or would the BMS kick in and protect from over voltage?? This is all theory at the moment so I am probably missing something.. Could you suggest a charger method. Am I on the right track?

2018 model Pedalease Estar MTB electric mountain bike 1000w or 1500w rear hub motor with option of 48v 10ah, 48v 11.6ah and 48v 17ah lithium battery. Motor: Pedalease 1000W or 1500w rear drive brushle…

You will find here all Li-Ion/LiFePO4 EBike battery packs and cells, battery management system(BMS). This category includes 12V~72V Li-Ion/LiFePO4 EBike battery packs and cells, EBike bottle battery, high power battery and high C-Rate cells, 4~24 cells in series Li-Ion/LiFePO4 bleeding balancing BMS and 5~13s smart BMS.

You’ll see two dots where http://electricbikecharger.com weld was performed. Test the weld by pulling on the nickel strip (if it’s your first time using the welder). If it doesn’t come off with hand pressure, or requires a lot of strength, then it’s a good weld. If you can easily peel it off, turn the current up. If the surface looks burnt or is overly hot to the touch, turn the current down. It helps to have a spare cell or two for dialing in the power of your machine.

The Panasonic NCR18650B cells you have are very good quality cells. I used similar cells also made by Panasonic, but mine are the NCR18650PF (not B). The difference is that yours have more capacity (mine are 2900mAh, yours 3400mAh) but yours have a lower constant current draw rating. I don’t remember what it is off the top of my head, but I don’t think it’s much more than 5A per cell. So just make sure that you either use enough cells in parallel and/or limit your controller to not draw more power than the cells can handle. Check the cell specification sheet which you can find on Google somewhere to ensure that you are staying within the cells’ limit.

Battery packs are made up of individual cells connected together. Each cell has a more or less constant voltage dependent on its chemistry. For NiCad/NiMH, this is about 1.2V, for lead acid it is 2.0V, and for lithium cells it is on the order of 3.7V. Typical ebikes and scooters are designed to run on 24, 36, or 48 Volts, so a number of cells have to be series connected into a ‘battery’ that has the desired net voltage. A nominal 36V pack could be made from 10 lithium cells, 18 lead acid cells, or 30 NiMH cells.

When comparing between battery chemistries, one of the most relevant metrics is the Energy Density in watt-hrs / kg. This figure says how heavy a battery pack will have to be to achieve a certain range. For Lead Acid it is 20-30 whrs/kg, for NiCad it is 35-40 whrs/kg, NiMH is 50-60 whrs/kg, Li-ion is ~110 whrs/kg, and Li-Polymer is up to 160 whrs / kg. Knowing these values makes it easy to project the weight of a pack without having to look up data from the manufacturer.

The BMS I chose is a 30A maximum constant discharge BMS, which is more than I’ll need. It’s good to be conservative and over-spec your BMS if possible, so you aren’t running it near its limit. My BMS also has a balance feature that keeps all of my cells balanced on every charge. Not all BMS’s do this, though most do. Be wary of extremely cheap BMS’s because that’s when you’re likely to encounter a non-balancing BMS.

A big downside of lithium batteries is that they are much more expensive than lead acid batteries. Prices vary depending on the voltage and capacity of the lithium battery, but standard ebikes usually have lithium batteries starting in the $300 range and rising quickly from there. Most bikes I build have lithium batteries in the $400-$500 range.

There are many different types of lithium ebike batteries to choose from. I’ll give a short summary of the different types of electric bicycle specific lithium batteries here, but you can get a more detailed description as well as the pros and cons of each type of lithium battery in my article Not All Lithium Batteries Were Created Equal.

“battery electric scooter electric bike build”

I see, so regarding the question about building backup batteries, applications where the existing backups are NiMH or NiCd and are already designed into a charging system should really get NiMH replacements rather than Li-ion. I didn’t realize older batteries used something other than CC-CV.

Oh, one last thing. If you have a poorly formed connector or the wires are fraying, that can increase resistance and cause a voltage drop that might trip a cutoff condition. Just another thing to check for.

Here at Grin we’ve been dealing with ebike batteries for a very long time during which we’ve offered over 100 variants of NiCad, NiMH, LiFePO4, LiPo, and Lithium-Ion packs in all kinds of voltages, geometries, and capacities. It’s been a love/hate relationship over those years, but the more recent mass production of 18650 lithium cells for high power consumer goods like power tools has shifted things to the love side, with ebike batteries that are cheaper, lighter, and with far longer life span than we could have ever wished for in the past. We’re happy to stock both frame mount and rear rack mounted batteries from 98 watt-hours to 1100 watt-hours in size to suite the needs of most electric bicycle conversions. 

Power ratings of E-bike kits and the C-rates of batteries for sale are ALL highly suspect. The endless-sphere authority on batteries and their batteries for e bikes is Doctor Bass. He has nothing to gain from misrepresenting any chemistry or battery manufacturer. I must admit I am annoyed if a new battery is claimed to be a 5C chemistry, but testing shows it to survive better at 3C, however…a misrepresented battery that is a true 3C is still a good thing.

It makes very little difference whether you have a small geared motor, a large direct drive motor, or a mid-drive motor. The mileage and range figures for a given battery have to do with how you use the ebike, not which motor system is on the bike.

Yes, it’s technically possible, but sometimes it is easier said than done. If the cells are on the edge of your battery, it’s much easier to cut them out (by the nickel, not by cutting the actual cell!) and replace them. If they are sandwiched in the middle of your pack then you’ll have to do a lot more pack surgery to get in and replace them. But yes, it’s possible to just remove them and replace them with new, good cells of the same capacity.

For people who are new to the hobby, ready-made lithium packs are the way to go. Several manufacturers offer ready to go Lithium packs with a built in Battery Management System (BMS) at affordable prices.

Motor: 36V 350W brushless motor. · Lithium Battery— The removable 36V 10AH Ion lithium battery, equipped with smart lithium battery charger can make you ride up to 32kms. And lithium battery could a…

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Safety disclaimer: Before we begin, it’s important to note that lithium batteries inherently contain a large amount of energy, and it is therefore crucial to handle them with the highest levels of caution. Building a DIY lithium battery requires a basic understanding of battery principles and should not be attempted by anyone lacking confidence in his or her electrical and technical skills. Please read this article in its entirety before attempting to build your own ebike battery. Always seek professional assistance if needed.

I would advise against connecting one battery to the other’s charging port. That charging port, as you correctly stated, is wired to a charging circuit on the BMS which is usually meant to take 5A max, sometimes less, whereas the discharging side of the BMS usually puts out at least 15A, sometimes much more. You can easily fry your BMS by connecting a second battery to its charge port.

The best method is to use a trusted vendor. They interact with the cell providers and are the best way to confirm whether cells are fake or not. It can be incredibly difficult to tell whether a cell is fake or not just by picking it up from the table. There are some giveaways like different printing on the wrapper, slightly different color, different stamp, different weight or different shell design, but all of those can be mimicked. That’s why I use only a handful of vendors that I’ve worked with continuously and who I know have always given me good quality cells. I had to go through some low quality ones until I found the sources I buy from now.

Regarding you question, if I understand you correctly, it seems that your 18650 lithium battery will be smaller than the old NiCad battery, so you have extra room in the battery box that needs to be filled, correct? My recommendation is to use some type of fairly rigid foam to fill the space. It adds almost no weight and it also helps cushion the battery pack.

This is what I refer to “small cells”, the 18650 (cordless tool) type cells which need to be spot-welded or soldered together to form a large pack. The big advantage of these cells is they offer better cooling because of the nature of their shape to the LiPo soft pouches, and therefore have the capacity to last longer.

I have an old 12V DC Brush Motor which its consumption is around the 12A, 13 A and I built a Battery pack, with two groups of batteries, (4S6P)+(4S6P), which makes a total pack with 14,8V 30A. To make this battery pack I used 18650 Samsung Cells 2600 mAh.

If not possible, try charging them individually. Some of them might come back but others might be dead. The tricky thing is that they will likely not be able to deliver their full capacity anymore and the actual capacity will likely vary from cell to cell. Two year old cells at a very low voltage are quite a gamble.

Lithium batteries are not 100% fire-safe. Some batteries are more dangerous than others, depending on the chemistry, whether it has BMS or not, and what kind of casing the battery is in. If the battery is cased in metal its less likely to burn your garage down, than if its encased in plastic. Also be aware that all BMS’s are not alike, some are good and others are crap, just like anything else in life.

The exact amount of range you’ll get per battery and motor varies greatly and depends on factors like terrain, speed, weight, etc. Suffice it to say though that if you double your current battery capacity, you’ll see an approximate doubling of your range as well.

LiPo packs that are homebuilt (without a BMS) can be extremely dangerous if you do not approach your battery with a lot of knowledge and care. Be sure to research extensively before building such a pack. Many E-bikers construct packs with no BMS using Turnigy/Zippy packs, acquired cheaply online through the Hobby King company which is based in China.  For those who risk running their batteries without BMS they still use sophisticated chargers to balance their packs and constantly monitor the health of their cells.

I am planning on making a 6S2P LifePO4 pack that has a voltage of 19.2V. I have a 6 cell BMS that does balancing (and that is intended to work with 6 LifePO4 cells). I need some help selecting a charger to charge this pack, however, particularly regarding the charger’s voltage specification.

The very first consideration when choosing a battery pack is ensuring that it can handle the current draw of your motor controller. If you have a 40A motor controller, but your battery is only rated to deliver 25A max, then either the BMS circuit will shut off the battery at full throttle, or the battery will be stressed and have reduced cycle life.  The converse, having a battery that has a higher current rating than what your controller will draw, is no problem at all. In fact, it can be quite beneficial. 

If I regroup my 12 paralled cells in 10 modules, can I then join these in series using single wires (one for neg, one for pos) between modules, instead of wiring each terminals of each cells like you are doing. Could this affect BMS and/or have any negative impact on cells balance?

I’d recommend going with a cell that can output 10A, giving you 40A continuous power rating. You’ll use less than that, meaning the cells will be happier (and cooler). Something like the Sanyo 18650GA or LG MJ1 would give you good power and capacity (both are around 3,400 mAH per cell).

A High-performance Motor acheives a top speed of 20-30km/h with a range of 20km means your ebike commute just got easier. Power: Under 500W. Material: Aluminum Alloy. Outdoor Foldable Electric Power A…

Most inexpensive NiMH packs are not really designed for discharges greater than 1C. That means that if your ebike draws 15 amps on average, you would want a pack that has a capacity on the order of 15 amp-hours more.

36v 10Ah Bottle Type Battery. Rated capacity: 10Ah. 36v 14Ah Rear Rack Type Battery. Rated capacity: 14Ah. 48V 14Ah Rear Rack Type Battery. Recommended to be used with 36V 250W electric bicycle motor.

“battery for a scooter scooter batteries 36v”

3. Lastly, I assume if the BMS & battery were able to produce the 50A X 24V watts of 1200W that my electric motor would only ever use the 500W it is rated for? As in the E bikes controller would only draw around 500W?

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Features: It is so light weight , easy to transport and to take it. It is eco-friendly and safe to use it. The battery holder is so stable and sturdy. Super powerful,safe and reliable. Suitable for bi…

Typically you can expect somewhere between 25 and 70 miles of travel on a single charge of an ebike. If you’re riding hard on full power expect less; manage your battery life well and you could get more.

The battery cells have now been assembled into a larger 36V pack, but I still have to add a BMS to control the charging and discharging of the pack. The BMS monitors all of the parallel groups in the pack to safely cut off power at the end of charging, balance all the cells identically and keep the pack from being over-discharged.

I hope not to have to replace the whole battery pack and wondering if it can be salvaged by replacing the just the dead cells and burnt connectors, or do you think the damage is too extensive to be worth repairing it?

The controller that came with my ebike conversion kit just has the label ’48v 1000w’ on it and there are no other specifications anywhere to be seen. I have emailed the suppliers asking if I could have http://electricbikebatterys.com full list of specifications for the controller but am yet to hear back from them.

I would prefer to go with lithium, but I have a couple of 75 volt (i think) cells from a UPS that are brand new. They are built from regular 12v (sixteen total) sealed lead units and would make the initial investment in an ebike that much more reasonable. One huge downside is that I hope to use the folding ebike in my homebuilt aircraft. As with ebikes, excess weight is to be avoided!

Good question. The answer comes down to the difference between “nominal voltage” and “actual voltage”. LiFePO4 cells are nominally called 3.2V cells, because this is their voltage in the middle of their discharge curve, at about 50% discharge. They actually charger to a higher voltage though, about 3.7V per cell. That means that you need a charger that has an output voltage of 3.7V x 6 cells = 22.2V DC. This is going to be a bit harder to find because most LiFePO4 packs come in multiples of 4 cells, (4, 8, 12, 16 cells, etc) so finding a charger for a 6S pack might take some searching. This charger is a good quality one meant for 8 cells (output voltage of 29.2V DC) but if you put a note in the purchase order, the seller can adjust the output for 6 LiFePO4 cells (22.2V DC). http://www.aliexpress.com/store/product/aluminum-shell-24V-29-2V-3Amper-Lifepo4-battery-charger-high-quality-charger-for-8S-lifepo4-battery/1680408_32274890691.html

I am planning to build a 14s7p pack with the GA batteries for a little over 1 KW of power. I went to the BesTechPower site and their are several 14s BMS’s there. Which one would you recommend for a battery this size? Can you send/post a link to the specific on on their site? thank you.

9S, 32.85VDC, 2890MAH, 94.93WH. THE ENERGY DENSITY OF THESE CELLS ARE SPECTACULAR. YOU GET A POSITIVE AND NEGATIVE LEAD WIRE AND ALSO BALANCE CONNECTORS IF YOU WANT TO BALANCE THE CELLS. IF YOU BUILD …

Hi Micah,I am from INDIA want to construct a 36v,15 ah,peak current 15 amp,continuous current 6 to 8 amps. Now ipurchased 20 pcs new IFR 18650 lifepo4 rechargeable cells,and a BMS36v,lifepo4 BMS12s forE.Bike lithium battery pack 12s,36,v,PCm.How many cells total i have to use for my aim?What kind of charger (specification) i have to purchase? Your article and reply to questions are interesting.please guide me.

Alibaba.com offers 176,519 electric bike battery products. About 29% of these are electric bicycle, 22% are rechargeable batteries, and 8% are electric bicycle battery. A wide variety of electric bike battery options are available to you, such as 36v, 24v, and 48v. You can also choose from lithium battery, lead acid battery. As well as from 10 – 20ah, 21 – 30ah, and > 40ah. And whether electric bike battery is paid samples, or free samples. There are 176,478 electric bike battery suppliers, mainly located in Asia. The top supplying countries are China (Mainland), Taiwan, and Vietnam, which supply 99%, 1%, and 1% of electric bike battery respectively. Electric bike battery products are most popular in North America, Western Europe, and Northern Europe. You can ensure product safety by selecting from certified suppliers, including 39,164 with ISO9001, 14,565 with Other, and 6,300 with ISO/TS16949 certification.

i noticed that bms installation is different (as i guess) from the video (https://www.youtube.com/watch?v=rSv9bke52eY&index=10&list=LLDXj2cy8mbQoc0dz3RO3zFw) i have watched before. In this video bms wires were connected on the negative poles of batteries lifepo4. In my amateur opinion i could not understand how we organize BMS connections for my 13s pack. if you illuminate me, i will be preciated.

“e bike battery _bike battery power”

Well, we here at electricbike.com are glad you asked! As of this month (Feb 2013), nobody is selling completed packs with the new NCA chemistry to the public, but the cylindrical cell that will be up to bat next is…

If you are using 2.5AH cells then yes, it will be 5AH with a 2p configuration. If you use cells with higher capacity, like Sanyo GA cells that are 3.5AH, then you’ll have a 7AH pack with only 2p. Make sure your cells can handle the current that your electric scooter (and namely the controller) will try to draw from it.

Next, we’ll need to wire multiple 18650 cells in parallel to reach our desired pack capacity. Each of the cells I’m using are rated at 2,900 mAh. I plan to put 3 cells in parallel, for a combined capacity of 2.9Ah x 3 cells = 8.7 Ah. The industry abbreviation for parallel cells is ‘p’, meaning that my final pack configuration is considered a “10S3P pack” with a final specification of 36V 8.7AH.

My daily driver ebike has 8 cells paralled (14s8p) and it’s been working great for a long time. You can certainly make two 13s4p packs and parallel them after the fact, but don’t be afraid of making a single pack. As long as you use good quality cells, the risk of a parallel group dying is incredibly small.

Lastly, regarding the spot welder. I actually prefer to use the kind like you said, with the two arms that lift up and provide equal pressure at each weld. The kind with two long welding cables like this welder has both options which is nice, especially for if you need to reach to the middle of a pack to make a repair or if you missed a weld. I mostly use the short rigid arms though and just weld one row at a time before adding more cells – that way I can reach all the cells with the short arms.

36V 10ah Lithium battery (Included with the battery is the charger and mounting Bracket). Standard Fat Wheel 26 in by 4in Front Wheel 500w brushless motor hub (works with disc brakes). Pedal Assistanc…

A recent quote from ES member SamTexas on claimed max C-rates: “…I have in front of me Samsung’s own Nickel (Manganese) 18650 cells….I have tested these cells at 3C continuous and they do deliver full capacity at that rate. Push it to 5C and they become hot and capacity is greatly reduced…“

As long as you monitor your pack voltage so you don’t go too low during rides, then yes that would work. You’d simply run your discharge negative wire straight from the -1 terminal of your battery out to your controller, instead of from your -1 terminal to your BMS’s B- http://electricbikeframes.com But that removes the ability for the BMS to cut off the current when the voltage goes too low, so you’ve got to watch for that.

36v 10Ah Bottle Type Battery. Rated capacity: 10Ah. 36v 14Ah Rear Rack Type Battery. Rated capacity: 14Ah. 48V 14Ah Rear Rack Type Battery. Recommended to be used with 36V 250W electric bicycle motor.

Finally, have you used the type of spot welder shown with hand held probes? Can see the benefit of greater reach, but do you know if this gives as neat a result (my spot welder there is a very firm press up to activate, hence the discharge only occurs when the tips of the welder are pressing the strip firmly against the top of the cell so i assume ensuring a tight weld)

The ShippingPass assortment is continually being optimized. Products are added and removed for lots of reasons, but the main reason is to show items that we’re 100% sure we can deliver within the promised timeline.

Actually, it is not recommended to use protected cells in ebike builds. There a few reasons but the main ones are 1) unreliability of the protection circuit, 2) many points of failure, and 3) lower discharge current of individual cell protection circuits.

There are many different types of lithium ebike batteries to choose from. I’ll give a short summary of the different types of electric bicycle specific lithium batteries here, but you can get a more detailed description as well as the pros and cons of each type of lithium battery in my article Not All Lithium Batteries Were Created Equal.

You’re absolutely right that doubling the capacity of the battery by running two packs in parallel will essential halve the load on each pack, but I still don’t think it would get it down to the level that you could rely on compression fit spring contacts to safely carry that current, let alone the balance issue of not having the 4 groups individually paralleled at the cell level.

I’d recommend going with a cell that can output 10A, giving you 40A continuous power rating. You’ll use less than that, meaning the cells will be happier (and cooler). Something like the Sanyo 18650GA or LG MJ1 would give you good power and capacity (both are around 3,400 mAH per cell).

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Also changing the fuse to a higher one could cause the wires to start a fire and the whole house would burn down if the wires are not thick enough. Also in sweden a fuse gets bigger as they are rated higher so you can fit a 20A fuse in a 10A slot, for safety.

Yep, that explains it. I was going to say that it sounds either like a defective BMS or more likely a connection error. B1 is definitely the negative end. Also some BMS units have B1- and B1+, others just have B1+. If it has both, it will have X+1 sense wires, where X is the number of series cells in the pack.