“lithium bike +e bike batteries”

With the voltage known, the next item to figure out is how many amp-hours will be required to achieve your desired trip distance without the battery running flat. This depends of course on how much pedaling you contribute to the effort, how fast you are traveling, and the terrain you are on. The following table is based on minimal pedaling effort.

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.

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 cells 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.

Spot welders for batteries aren’t the same as most home spot welders. Unlike the large jaw spot welders for home workshops, battery spot welders have the electrodes on the same side. I’ve never seen them for sale in the US, but they can be found pretty easily on eBay and other international commerce websites. My full time use welder is a fairly simple model that I got here. A highly recommended source for a slightly nicer spot welder design (pictured below) with both mounted and handheld electrodes can be found here.

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”.

You’ll also want to test out the battery with a fairly light load in the beginning. Try to go for an easy ride on the first few charges, or even better, use a discharger if you have one. I built a custom discharger out of halogen light bulbs. It allows me to fully discharge my batteries at different power levels and measure the output. This specific battery gave 8.54 Ah on its first discharge cycle at a discharge rate of 0.5c, or about 4.4 A. That result is actually pretty good, and equates to an individual average cell capacity of about 2.85 Ah, or 98% of the rated capacity.

Remove all metallic jewelry. This is another tip that I can give from experience. Arcing the contacts on your battery is not something you want to happen ever, and especially not against your bare skin. I’ve had it happen on my wedding ring and once even had a burn mark in the shape of my watch’s clasp on my wrist for a week. Now I take everything off.

This makes sense. Yes, it would be possible. You could wire balance connectors and extra discharge plugs to make three packs out of your one 13s pack, such as two 6s packs and a 1s, or two 5s packs and a 3s, etc. Then you’d charge each one, one at at time, using your imax B6 charger. It would take a while, but that’s how you’d do it. Just be careful to not get your connectors confused, as you’ll have three sets of balance wires and three sets of discharge wires.

Yes, as I understand it, Nimh and NiCd batteries charge differently. I understand lithium batteries much better than those other technologies, so don’t quote me on this, but I believe that Nimh and NiCd cells have current powered through them and the voltage control is different, as opposed to lithium cells that draw current at the charger’s preset rate and then keep drawing until the voltage floats to 4.2V, at which point the already tapering charger’s current supply is cutoff and the battery is fully charged.

My question for you is, if I just want to run a BMS for balance charge purposes only and want to wire the battery discharge directly to the motor how would I do that? Would that be a good solution as long as I monitor battery pack voltage during rides?

I guess I’ll just have to risk some deterioration on the cells. I don’t think there’s much of an effect, as I did it on an old 18650 cell to test. The joint and surrounding areas were cool to the touch within 1-2s of removing the heat.

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 don’t think there is any danger to parallel more than 4 cells. Tesla cars have literally hundreds of 18650 cells just like these paralleled. The issue is that if you ever did have a problem with one cell, like a factory defect that caused it to short circuit, it could die and drag all the other cells down with it, killing the entire parallel group. That’s why Tesla uses individual cell fusing, but that’s not really employed on the small scale like for ebikes.

48 volt 1500 watt motor 48 volt 16.5 amp Samsun cell high quality battery 2amp charger, charges in 6 hours plus battery has USB port to charge your phone Top speed 35mph high torque Comes with every t…

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.

HERE ARE 100 GENIUNE LG LGDAS31865 18650 2200MAH CELLS. YOU CAN’T FIND A BETTER DEAL THAN THIS. Capacity: 2200mAh. THE PHOTOS SHOW HOW WE GET THESE IN AND BREAK THEM DOWN. STOP GETTING RIPPED OFF AND …

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.

Most lithium batteries that are designed to mount to ebikes also come with some form of locking system. These have varying degrees of effectiveness. The type with a little pin that slides into a thin sheet of steel are the easiest to steal by mangling the thin steel locking plate. Just take a look at your battery and ask yourself “how easily could I steal this battery if I had some basic hand tools and a 60 second window of opportunity?”

Rechargeable Electric Bicycle Batteries 48V 20AH Lithium Ion Battery. These are 18650 cell based batteries (similar 18650 type cells are used in the Tesla car). Use it for ebike, scooter etrikes. Batt…

Bigger is better! And I know a better way batteries should be made. I use 560 of the Panasonic 18650b battery cells with 3.4AH per cell, wich in the end gave me (7kwh battery ebike!), that’s more than 300+ miles battery range easy. And I’ve learned that these batteries can be assembled like Lego blocks instead and eliminate harmful heat from soldiering, and wastful glueing. The benefit is a battery pack that can have removable, repairable, and reconfigurable battery cells! Its called (battery blocs) patiented by Shawn McCarthy. Unfortunatly its not the cheap method and requires a 3d printer to make. It spaces the cells slightly apart for better air cooling. Mine are packed into 4 PVC tubes run either at 103.6v or 51.8v. I believe along with some experts that a BMS is not required and can cause battery cells to fail early!, and a proper set voltage monitor and regulator prevents over discharge damage and you need to a timer and monitor the cell voltages with cell monitors while charging. Cooling setup would be a pluse to extend life. That’s all for now, best luck to all battery builders.

However, when you factor in the shorter life cycle of lead acid batteries, they become comparable to lithium batteries over the entire life of the electric bicycle. For example, a lithium battery may cost five times the price of a lead acid battery, but it could easily last five times as long as well, making the price about the same over the life of the lithium battery. You’d have to buy at least four replacement lead acid batteries (maybe even more) by the time your lithium battery finally kicks the can.

So I’m going to first use a wider (285 mm to be exact) but shorter piece of shrink wrap to go around the long direction of the pack. That will seal the ends first, and then I can go back with my long and skinny piece of heat shrink to do the length of the pack.

One of the main disadvantages of lead acid batteries is their weight. There’s no beating around the bush here, SLAs are HEAVY, as you might guess by the inclusion of “lead” in the name. You’ll need a strong mounting solution on your ebike to handle the extra weight of SLAs. You should also be aware that lugging that extra weight around is going to negatively impact your range. The best way to improve the range of any electric vehicle is to reduce weight, and SLAs are kind http://huntneqip.com going the opposite way in that regard.

“lithium bike battery electric bike batteries for sale”

I have an unrelated problem. I am prototyping a 1/3 scale model of a top fuel funny car.It’s 5 ft long, 2ft wide, wt. is approx. 100lbs.. I need to go 120 mph in under 4 seconds in 333 feet. Will the 5405 mtr. suffice? I know your going to ask alot of tech. questions but thats all I have for now.Any help in this quest for speed is greatly apprecated. Thank you robert lathrop

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

the problem i have and the bit im confused on is this, i understand the negative on the entire pack goes to the negative on the BMS and the positive of each parallel cells goes to each sense wire but where are the charge and discharge wires going ? am i corrrect in saying that the positive of the pack goes to the charge and discharge socket on the BMS and that when the pack receives its charge it charges the pack and the discharge is when the pack is under load from the output of the pack i.e what ever its connected to for example your bikes motor? in your tutorial you havent shown how you connected the parallel groups of batteries together in series to give you the final pack voltage and capacitance but i’m assuming you linked them in series to get the toal 36v but on the pictures the first and last cells are split compared to the doubled up cells you have through out. am i also correct in saying that if you have 2 batteries connected together to form a cell then you dont need a sense wire on each battery because the two batteries are considered to be the same battery and when they charge and discharge they equalize as one shunts the other ? sorry for so many questions i have googled and googled and googled and as Einstein once said the definition of madness is doing the same thing over and over and expecting a different result, many thanks in advance .

One other unrelated question: Do commercially available eBike batteries generally use off-brand cells for their assembled batteries to bring cost down, or similar to the cells, do reliable eBike companies use name-brand cells and off-brand internet vendors use off-brand cells?

The Panasonic NCR18650PD cells can be purchased at Fast Tech dot Com, who reliably processed and shipped my transaction. Good prices, too, from this Chinese-based vendor. I “tested the waters” by buying just 4 cells first and will certainly be buying more from them. I’d like to make my http://bestelectricbikebattery.com e-bike pack with these cells and further inquired to AllCell to see if I could obtain one of their PCM blocks. Unfortunately, they will only sell these on bulk wholesale basis to established pack-building businesses. The DIY pack builder will have to explore other options.

Having built a 13s4p battery to the best of my ability and hooked it up to my 48V 1000W ebike conversion kit…. the lights on the throttle turned on and the wheel spun! Initially I thought the project was a success but after mounting the battery and controller onto the bike and taking the bike for a test spin I ran into a major problem.

The battery pack is one of the defining aspects of any PEV project; by and large it determines the weight, range, and cost of the vehicle. For these reasons a solid understanding of the various battery types is more than a little useful.

“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 but offers a low specific energy.

When soldering these wires to the nickel strip, try to solder between two cells and not directly on top of a cell. This keeps the heat source further from the actual cell ends and causes less heating of the battery cells.

Hi Sundaram, I’m not aware of many 18650 LiFePO4 cells, are you sure you are using that chemistry instead of standard lithium ion? Perhaps can you provide a little more detail about the specific cells you’re using?

Spot welders for batteries aren’t the same as most home spot welders. Unlike the large jaw spot welders for home workshops, battery spot welders have the electrodes on the same side. I’ve never seen them for sale in the US, but they can be found pretty easily on eBay and other international commerce websites. My full time use welder is a fairly simple model that I got here. A highly recommended source for a slightly nicer spot welder design (pictured below) with both mounted and handheld electrodes can be found here.

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.

Many retailers suggest charging the battery at least once a month if the bike is not ridden much, and say that the more the bike is ridden, the stronger the battery will be. All batteries, though, will deteriorate in time and they will need to be replaced and disposed. When that time comes, it’s best to ask your local retailer how to dispose of the battery, but bear in mind that local authorities should provide recycling and disposal facilities.

Regarding your second question: I wouldn’t say the max amperage of the BMS is “dependent” on the controller, but it should be chosen with consideration to the controller. Think of it this way: your controller is what decides how much current your battery is going to supply. The controller is basically pulling that current from your battery. If it’s a 20A controller, that means the most it will pull out of your battery is 20A. So if you plan on riding in a style that uses full power for long periods of time (like hill climbing, dirt riding, etc) then you’ll need to make sure your BMS is rated at least 20A continuous. However, most people that ride on flat roads spend very little time at peak current. My ebike’s controller is a 22A unit, but I spend most of my time around 10-15A when cruising. A 20A continuous BMS would be good insurance in that case, because it means my BMS is rated to handle more continuous power than I generally will pull through it.

I’m a little worried that your batteries aren’t what you think they are. If they really are AA sized, which is rare in the lithium battery world, then they are not 3,000 mAh. Next, 10 cells in series is going to give you 36V, which is twice what your 18V drill is rated for. 5 cells in series and 2 in parallel would be a better method. I usually recommend a BMS but you can skip it if you have another way of diligently monitoring your cell voltages and then charging using an RC style balance charger like an iMaxB6 charger through an JST-XH connector.

Thanks for the info! I have read about builders that used Sony Konion LiMn cells that were removed from Makita Drill packs. The constant theme of their reports show that the thing they seem to like the most, is that the cells seem to just stay in balance. So much so that, several have built packs with no BMS. If there is a measurable LiMn shelf life issue compared to other chemistries, it doesn’t seem to bother the DIY pack building crowd.

With the voltage known, the next item to figure out is how many amp-hours will be required to achieve your desired trip distance without the battery running flat. This depends of course on how much pedaling you contribute to the effort, how fast you are traveling, and the terrain you are on. The following table is based on minimal pedaling effort.

Sorry Benoit, but that won’t work. The BMS will expect the full 10 cells and when it sees that cells are missing, it will assume they are at 0V and not provide any power. You need a 7s BMS, which are pretty commong. 8s will be harder to find for li-ion, but you could do 8s with LiFePO4 and those 8s BMS’s are common.

Thanks for the kind words! Unfortunately I don’t have access to a schematic. I got that BMS from a Chinese reseller and I would be surprised if even he has a schematic. I have seen people parallel BMS boards on a single pack to get higher current output but I haven’t tried that myself.

If you are thinking about building your own LiPo pack, a 48V / 10-Ah battery pack can be made for around $300. However to undertake this project you should research extensively on www.endless-sphere.com on how to build and take care of your pack. Expect hours of reading before you are ready to build a pack of your own.

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.

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

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 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.

I understand that the Ebay battery may run low, but as it is running in parallel to the “Whale”, I’ simply use the “Whale” LED display as rough guid to both batteries charge state (assuming I fully charge both batteries each time before I ride).

In the rush to upgrade from lead acid to the latest NiMH and lithium packs, it seems that most companies forgot about the old venerable Nickel Cadmium battery as a suitable option for ebikes. Although they are somewhat heavier than the NiMH and lithium options, they are still a substantial weight savings over lead. NiCd packs have had a solid and proven track record in demanding rechargeable battery applications.

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.

With the Multimeter I see that is everything OK, I see the voltage of the 4S in B+ and P-, but when I connect the motor nothing happens, the voltage goes to zero. At this moment I want to discharge the batteries and I connect B- to B+ and is working OK, of course.

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.

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.

If you want to test cells from different vendors, the best thing to do is run them through a discharger, preferably a fancy graphing one, and preferably at a high current rating close to the maximum discharge rating. Fake cells are lower quality and won’t be able to provide the same capacity, and will have a larger voltage sag under higher loads.

12V increments are easier to do with LiFePO4 due to the 3.2V per cell. So for 12V, 24V, 36V and 48V they go 4 cells, 8 cells, 12 cells and 16 cells. Li-ion is more annoying because the 3.7V per cell doesn’t play as nicely. The general convention for the same 12V increments is 3 cells, 7 cells, 10 cells, and 13 or 14 cells. 3 cells is just a bit low for a 12V system (about 11V nominal) but will work for most applications until the voltage drops to about 9.5 or 10V depending on your device’s cutoffs. Regarding the balancing issue, if you’re using those packs that claim to remain in balance then I’d imagine you can just trust them. If their packs had problems with balance then they’d probably be having tons of returns. Worst come to worst you can occasionally open the case and measure the cells to make sure they are all staying balanced. One word of advice: be very careful with the series/parallel switch setup. If you make a mistake or the switch melts you could end up shorting your batteries and ruin the whole lot…

I’m wondering, what do you do for 6V or 12V applications where the correct number of in-series cells is ambiguous? For example, if I’m replacing a 6V SLA battery, it seems like the existing charging system would set a 1s battery on fire, but wouldn’t be sufficient to charge a 2s battery. Are there BMS’s that have VRs to step up the voltage from the charging system to the battery, and step down voltage from the battery to the charging system to facilitate a 2s battery for the application?

This makes sense. Yes, it would be possible. You could wire balance connectors and extra discharge plugs to make three packs out of your one 13s pack, such as two 6s packs and a 1s, or two 5s packs and a 3s, etc. Then you’d charge each one, one at at time, using your imax B6 charger. It would take a while, but that’s how you’d do it. Just be careful to not get your connectors confused, as you’ll have three sets of balance wires and three sets of discharge wires.

RC packs may be fine for enthusiasts that know what they’re doing, but even telling others about them scares me! FIRE! And secondly, they typically don’t have any BMS so don’t have any inherent protection from over-under voltage or balancing. FIRE!

“electric bike motors and batteries _ebike battery”

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.

2. Lithium-Ion Shrink Wrapped Shrink Wrapped Lithium-Ion Batteries are housed in a soft PVC heatshrink material. It protects the battery from moisture and short-circuits, but not from being dropped or punctured. View Shrink Wrapped Lithium E-Bike Batteries

Finally found it. WOW!! Exactly what was needed. I struggle with conceptualizing verbal descriptions. You solved that! With the new JP Welder from Croatia my first welded build will soon be a reality. Thanks for all you do for eBiking!

That’s a tough one to answer. It depends on the power of the battery (typically 24, 36 or 48V), the power of the bike (limited in the UK to 250W), the bike’s battery management system, and the way you ride. Some bikes allow you to choose different levels of assist to prioritise speed or battery life, which makes predictions of battery life even more difficult.

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?

This is also why the common and affordable RC smart-chargers are powered by a separate DC power supply. Many RC enthusiasts spend a day at a park, and while flying an RC plane, they have several other battery packs that are charging from their cars 12V system.

I was wondering, though, if I could use thick gauge wire instead of nickel strips (copper wires are much more accessible). Would there be any downsides to that, given that I’m going to be using solder anyway?

Hey Brian, good question. You can actually do regenerative braking this way, the only problem is that you won’t be using the balancing circuit part of the BMS as it will charge straight back through the discharge circuit. Theoretically this is fine, with the exception of one specific case where this could be a problem. If you charged your battery at the top of a huge hill and then immediately rolled down that hill for a long time while using regenerative braking, you could actually overcharge the battery. That scenario is pretty rare though.

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Lithium Polymer is by far the lightest battery option out there. LiPoly cells that can handle very high discharge currents are becoming widely available and are especially popular in the R/C crowd for electric airplanes and helicopters, but ebike LiPoly packs are often made with cells that are only rated to 1C or 2C, and these don’t usually deliver a very good cycle life count. The cells are produced in a thin plastic pouch rather than a metal can, making them structurally quite vulnerable unless supplied with a rigid enclosure. Although Lithium Polymer has a reputation for being volatile and failing with spectacular pyrotechnics, there are companies making cells these days that are quite stable and can pass the fullUN 38.3 overcharging and puncture tests without any flames.

Short for bicycle motocross, BMX is a type of bike designed for dirt, street, flatland, and park rides. This is a more casual form of cycling, which riders enjoy for both pleasure and sport. BMX riding…

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…

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.

When it comes to buying your cells, you might be able to find a local source, or you can order them straight from Asia. I prefer the second option, as you’ll usually get a much better price going straight to the source, even when paying for international shipping. One caveat though: do your best to ensure that your source sells genuine cells and not knock-offs. Do this by checking feedback and using a payment method that ensures you can get your money back if the product isn’t as described. For this reason, I like to buy my cells on Alibaba.com and AliExpress.com.

Edit: if this article was helpful, you may like our newer article on the latest NCM/NCA battery chemistries, and also our article on high-performance batteries that are NOT made from LiPo. If you have narrowed your battery choice down to LiFePO4, make sure to check out Dogmans expert guide to LiFePO4 batteries.

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.

From what I can tell, the Faraday Porteur uses a 36V 5.8AH battery made from the same cells I used on the battery in this article. They only have two cells in parallel though, not three like in my battery shown here. You can build a battery just like theirs, or a 36V battery of any capacity. You could make a 12AH battery and triple your total range! Heck, you could even take a premade battery like this one and just replace the discharge cable with a XLR connector – it’d be an auxillary battery over three times as large as theirs for 2/3 the price!

Lithium Iron Phosphate is currently the most common lithium battery used in Ebike applications. It is considered the most stable lithium battery type available today (low risk of fire) and has a reasonably high life expectancy of over 1000 charges.

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. 

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.

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. 

Sure, it is possible to solder directly to the cells (though it can be tricky without the right tools). The problem with soldering is that you add a lot of heat to the cell and it doesn’t dissipate very quickly. This speeds up a chemical reaction in the cell which robs the cell of its performance. The result is a cell that delivers less capacity and dies an earlier life.

Wow, that’s a really interesting way to do it. So their auxiliary battery connects to the charge port of the primary battery, which means it’s not actually powering the bike but rather just charging the primary battery, which then powers the bike. Not the most efficient way to do it, but it’s simple and elegant.

In 2012, the future of LiPo in e-bikes looks bright. Most large EV manufacturers are focusing on LiPo as the lithium battery power of the future. LiPo technology is developing fast and becoming safer, more reliable, cheaper, and with a higher life expectancy. Since LiPo cells are being developed to be safer, more efficient and more economical (mostly for main stream products such as the automobile) the electric bicycle industry will be able to piggy-back and utilize the newly available technology at an affordable price. Currently, the latest “best” chemistry involves Manganese-Cobalt which is a lot more stable than the cobalt chemistry of the past.

For any other case, lithium batteries’ advantages greatly outweigh SLAs. Of course, for your specific ebike you might have other reasons that could sway you either way. At the end of the day, your ebike is all about you. I hope this information helps you make the right choice for your own battery needs.

The eZee flat packs are one of the nicer rear rack battery options that we’ve dealt with, featuring a locking on/off key switch, and a rail system to slide into the eZee double-decker rack or attach with our more universal CNC battery anchors. They hold up to 70 cells, allowing for both a 36V 19Ah (10s 7p) and 48V 14Ah (13s 5p) options. The 36V pack has UN38.3 certification for air shipping, and can handle up to 40A motor controllers fine, while the 48V pack shouldn’t be used above 25A.

Sorry Benoit, but that won’t work. The BMS will expect the full 10 cells and when it sees that cells are missing, it will assume they are at 0V and not provide any power. You need a 7s BMS, which are pretty commong. 8s will be harder to find for li-ion, but you could do 8s with LiFePO4 and those 8s BMS’s are common.

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I wouldn’t say incompatible but us 220 uses the full phase peak to peak of both legs of the elec drop. European and others uses a half phase (I believe) where zero to peak is 220v. Have you had a chance to look into this for me as my welder and box of new 18650’s are sitting idle waiting for me to start welding. Thanks

Why do we alternate sides of the pack during the welding process? We do it because in this way we connect the positive terminal of each parallel group to the negative terminal of the next group in line. That’s how series connections work: always positive to negative to positive to negative, alternating between the two.

The Panasonic 18650pf is a good cell, that’s the one I used here. I also like the Samsung 26F, though it’s a fairly low power cell, and the Samsung 29E which is a bit higher power cell. The Samsung 30Q is a fairly new cell that has good specifications batteries electrical doesn’t have as long a life – everything is a trade-off.

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.

Almost all consumer electronics that have a plug-in charger these days are powered with lithium batteries because they can store about 3 times more energy than NiMH. Small devices like cell phones, mp3 players, and other gadgets typically have lithium-polymer packs, as these can be formed in conveniently shaped thin rectangular pouches. Larger devices like laptops and the new lithium cordless power tools generally use cylindrical Lithium-ion cells of a size smaller than a ‘C’ but bigger than a ‘AA’. These are spot welded in series/parallel combination to give an appropriate voltage and capacity for the job.