“48 volt lithium bicycle battery _battery pack for electric bike”

We like to use Anderson Powerpole connectors as the standard discharge plug on all of our ebike battery packs. These connectors are ingenious since they are genderless, allowing you to use the same plug both on both a load and a source, and the connector design allows them to withstand the arc of inrush current when plugged into capacitive loads much better than bullet style plugs. For the charging port, we like to use the female 3-pin XLR plug standard. This is directly compatible with the Satiator charger, and the quality Neutrik XLR plugs are rated for a full 15 amps per pin allowing very rapid charging. Unfortunately, this option is not available for the smaller Hailong frame batteries and we are forced to use the lower current DC 5.5mm barrel plug instead.

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.

Secondly, what is your take on modular plastic battery spacers (e.g. http://www.ebay.co.uk/itm/50x-EV-Pack-Plastic-Heat-Holder-Bracket-Battery-Spacer-18650-Radiating-Shell-New/351681365193?_trksid=p2047675.c100005.m1851&_trkparms=aid%3D222007%26algo%3DSIC.MBE%26ao%3D1%26asc%3D36381%26meid%3Dfc487881e617412ba361731154a742b5%26pid%3D100005%26rk%3D5%26rkt%3D6%26sd%3D262123820960). Clearly this adds a significant volume penalty and a smaller weight / cost one, but if this is not an issue then how would you rate vs glueing? I can see the benefit of having a space between the cells to limit heat / electrical conductivity in the event of some kind of melt down, but any thoughts?

The next consideration is ensuring that the battery is large enough for your required travel range; it’s no fun having a battery go flat before the end of your trip. In order to determine the range that you will get from a given battery, you need to know both the watt-hour capacity of the battery, and how much energy you use per kilometer. Sounds complicated? Not really. As a rule of thumb most people riding an ebike at average speeds consume about 10 Wh/km from their battery, and this makes the math very easy. If you have a 400 watt-hour battery, you can expect a range of 40km. A 720 watt-hour battery? ~72km

For a 24V 7s pack, I’ve used this BMS a few times and been quite happy with it: http://www.aliexpress.com/item/7S-Li-ion-Lipo-Batteries-Protection-Board-BMS-System-24V-29-4V-20A-Continuous-Discharge-350W/32336397316.html

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.

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There is some research into 18650 packs that use pressure connectors like in a remote control but most results aren’t impressive yet. It’s difficult to get a good enough connection to batteries electric scooter high enough power for ebike applications. The ones that are close to working use custom designed enclosures. Don’t attempt to do it with off-the-shelf 18650 holders with spring contacts — you’ll melt them in no time.

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.

So after buying a 48v 20 Amp battery from Ebay (and knowing very little at that point), I realized it didn’t have a BMS and heard rumors that if i attached it direct to the controller, it would see it as a short (controller would be closed) and blow the controller.

Hailong makes some of the more refined of the generic battery enclosures from china. You’ll see them online everywhere, stuffed with whatever cells and BMS circuit appropriate to the market being addressed. They secure to the water bottle eyelets on the down tube of your bike frame, and the narrow height of this pack design allows it to fit even on smaller or hybrid frame geometries that wouldn’t normally fit a pack. We have the smaller Hailong-01 enclosure in 36V (10s 5p) and 52V (14s 4p) layouts suitable for 20-25A current setups, and the larger Hailong-03 enclsoure in 36V 23.5Ah (10s 7p) and 52V 16.5Ah(14s 5p) sizes for higher current and capacity. 

Connections are made with solid Nickel strips, spot welder to each cell. Each cell and each series is tested before assembly. The BMS will prevent over charging and will balance the cells after a full…

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!

Please forward to every member of ur family of em3ev! Here it’s been a great ride! Tks guys for everything. I can do mtb again bcause of your kit. My lower back and my knee been injured badly and i got fibromyalgia so without ur help my bike …

Is it possible that the controller for this Rayos 600W (sorry thought it was 500W but it’s actually 600W) is inside the electric motor itself? I traced all wiring on the E bike but find no controller anywhere. Do you see anything majorly wrong with using a BMS to charge the cells but not discharge, as in sending the current from the battery directly to the controller / motor? I’ve been unable to find a BMS that can do 30A that isn’t very expensive. A side note, I was able to test amperage while riding and around 20A gets me 9 miles per hour, that is where my multimeter tops out! I’m 235 pounds. I’m guessing I need around 30A to get the 16 MPH I get now with the existing LiFePO4 battery pack.

I just found your article, and as if it were destiny, this is exactly what I am trying to do (build a battery pack with BMS, and charge with charger). I am new to this, however, and have a question or two…

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Your method of using the tubes might work but I still worry about how much current you could safely pull out of those connections. You can definitely charge the way you described but trust me, charging 2 or 4 cells at a time gets VERY frustrating. You’ll be spending days, maybe a week, getting your battery all the way charged again.

“…The wax is micro-encapsulated within the graphite matrix. When the wax melts, there’s enough surface tension between the wax and a graphite matrix that it doesn’t leak out. You could heat the material up to 300° C (570F), and it will become soft enough for a thumbprint, but it will remain solid…”

NiCd-Nickel Cadmium. This chemistry was half the size per a given power compared to SLA. But it has a low C-rate (Current producing capability) so anyone who made a pack out of them was restricted to low amps. There were no large packs for sale. E-bikers had to purchase rechargeable flashlight batteries and solder together a pack of a higher voltage, for which an off-the-shelf charger could be found to charge it up. Because of the low price of SLA chargers, 36V and 48V NiCd systems were common. When the price of nickel went up and the price of Lithium came down, NiCd died a quick death. Not even cordless drills use these anymore.

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.

The spacers you linked to make battery building a bit easier as you can set it up modularly, but as you indicated, they add a good amount of volume to the battery. I like to make my batteries as small as possible so I rarely use them. When I do, I use these ones, but it’s not very often.

Different batteries have different amperage capacities. Most cheap lithium batteries are not capable of putting out much amperage. If you have a 48 volt bike that performs well when using 25 amps, you are going to want a 48 volt battery that has close to a 20-Amp-hours or more.  If you want to eventually hot rod your ebike (read our hot rod hub motor primer here), you may want to  invest now in a high amperage battery. This will “future proof” your system by paying a little bit more now for the battery, but then you can program more performance from the controller in the future, if you want…

Now I’ve got all of my pack sealed in heat shrink with my wires exiting the seam between the two layers of shrink wrap. I could have stopped here, but I didn’t particularly like the way the shrink fell on the wire exit there, from a purely aesthetic standpoint. So I actually took a third piece of shrink wrap, the same size (285 mm) as that first piece and went around the long axis of the pack one more time to pull the wires down tight to the end of the pack.

A very affordable 13S BMS that I like is this 30A version, though it can take a few weeks or even a month to arrive since it’s coming all the way from China. http://www.aliexpress.com/item/13-lithium-battery-protection-board-48v-lithium-battery-BMS-30A-continuous-60A-peak-discharge/1741121963.html

The purchase price is often a turnoff for many people, but in reality $200 for a good hobby-level spot welder isn’t bad. All together, the supplies for my first battery, including the cost of the tools like the spot welder, ending up costing me about the same as if I had bought a retail battery of equal performance. That meant that in the end I had a new battery and I considered all the tools as free. Since then I’ve used them to build countless more batteries and made some huge savings!

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All the help and knowledge I’ve provided here on EbikeSchool.com is 100% free, and I try to assist readers as much as possible in the comments section of each article. If you want to support this site and help me keep it free (and ad free), consider checking out my ebook and video course on building ebikes.

“scooters battery _48 volt lithium bicycle battery”

To wire the BMS, we first need to determine which of the sense wires (the many thin wires) is the first one (destined for the first parallel group). Look for the wires to be numbered on one side the board. Mine is on the backside of the board and I forgot to take a picture of it before installing it, but trust me that I took note of which end the sense wires start on. You don’t want to make a mistake and connect the sense wires starting in the wrong direction.

18650 cells, which are used in many different consumer electronics from laptops to power tools, are one of the most common battery cells employed in electric bicycle battery packs. For many years there were only mediocre 18650 cells available, but the demand by power tool makers and even some electric vehicle manufacturers for strong, high quality cells has led to the development of a number of great 18650 options in the last few years.

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. 

Now the game plan here is to weld parallel groups of 3 cells (or more or less for your pack depending on how much total capacity you want). To weld the cells in parallel, we’ll need to weld the tops and the bottoms of the cells together so all 3 cells share common positive and negative terminals.

The battery maximum power = volts x amps, so if this 36V battery can deliver 30A continuous, that means it can deliver a maximum of 1,080 watts, though I would run it conservatively at a lower power level than that in most applications.

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

This pattern continues until we’ve got all 10 parallel groups connected. In my case, you can see that the first and last parallel groups aren’t welded on the top side of the pack. That is because they are the “ends” of the pack, or the main positive and negative terminals of the entire 36V pack.

These cells are distinctive due to their cylindrical shape and are about the size of a finger. Depending on the size of the battery you plan to build, you’ll need anywhere from a few dozen to a few hundred of them.

Another excellent answer, thanks so much! Now it has arisen a few related questions, if you don’t mind answering them. I’m using authentic Samsung ICR18650-26FM cells. I had already purchased a 24V 15A BMS before I slightly understood all of this. I was also able to obtain more cells since my original idea, so I was planning a 7S10P pack (around 30Ah), 70 cells total. I see each cell can do around 5A, making a 10P pack put out 50A total. If I stick with my 24V 15A BMS, that will give me 15A * 24V watts, or 360 watts total for my 500 watt motor. I’m going to number these to make it easier:

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.

I think it is much better to use a purpose built CV-CC (constant voltage, constant current) ebike charger. I 100% understand the desire to complete the project on the cheap, but I think that sometimes it is worth a few extra bucks as insurance to protect your battery which is worth many hundreds of dollars.

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.

Most people find that once they have an ebike, they use it for all kinds of applications and trips outide of just commuting, and the ability to go 50+ km on a charge opens up possibilities that wouldn’t have been possible otherwise. Plus, as the battery ages and declines in capacity, it still has more than enough range for your key commuting needs. Imagine if instead of getting an 8Ah pack, you purchased a 15Ah battery. Even if after 4-5 years it has lost 30% of its original capacity, that’s still over 10Ah and leaves plenty of reserve for your 24km commute.

I finished an ebike yesterday, but i found some major problems on it, The problem is while i riding the bike by throttling, some times the display light dims and low battery voltage caution icon is displaying in the display. and than display shutting off. after that if i try to turn it on again it wont work, so i removed the battery from controller and installed it again than works perfectly, it happens always so i want to remove and install battery again and again, so what is this problem, is this problem is in battery or controller?? Please give me a solution.

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.

Either way works, but my orange jig saves me one hot glue step which just makes for a cleaner looking pack. Of course it’s all the same after the pack gets covered with shrink wrap, so you can use any method you’d like. I’ve even found that some of those cylindrical ice cube trays are perfectly sized to hold 18650 cells. Cutting off the top would leave it clear for welding. I’d add some strong neodymium magnets to the backside to hold the cells in place like my orange jig has, but other than that it’s a perfect jig almost as-is.

I continued with all 10 sense wires, placing the last one on the positive terminal of the 10th parallel group. If you aren’t sure about which groups are which, or you get confused, use your digital voltmeter to double check the voltages of each group so you know you are connecting each wire to the correct group.

However… I’m thinking about extending the range of my 250W ebike (a Greenedge CS2) by wiring a battery in parallel as a one-off project. My thinking is that as it would halve the load on each of the batteries, it would reduce output current and voltage drop under load. This I’m thinking would allow use of a simpler constructions, since the stress on each cell would be reduced.

The most noteworthy battery supplier is based in the USA and is offering lithium packs based on high quality cells.  A new vendor in 2015 is Lunacycle.com , so…check them out for a multitude of different packs at a very reasonable price.

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.

Lithium Ion electric bike batteries are ideal for those that plan to ride longer distances and or more frequent trips. The commuters https://en.wikipedia.org/wiki/Electric_bikes battery, lithium batteries can stand two complete 100% discharges a day for years. Discharging the battery half way riding to work or school, then parking all day at half charge does no damage to a lithium electric bike battery. So the urgency to recharge immediately is not like SLA’s. Since discharging to 100% empty does not significantly harm lithium electric bike batteries, the usable range of the lithium electric bike battery is roughly double that of SLA’s. In typical electric bike use, Li-Ion batteries last from two to four years. Proper storage of Lithium Ion batteries is important when the electric bike will not be used for more than a few weeks. Unplug the battery from the electric bike, charge fully, and then store in a cool but not frozen, dry place.

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

20″ 250W 36V White Folding Electric Lithium Battery B ike. Motor: 36V 250W Rear Hub Motor. The 20” Sheep is a 36V 7AH Lithium Battery powered Electric Bicycle. This Folding Electric Bicycle is the per…

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

I placed the first parallel group positive side up, and the second parallel group negative side up. I laid the nickel strips on top of each of the three sets of cells, bridging the positive caps of the first parallel group with the negative terminal of the second parallel group, as shown in the picture.

Sizing a bike correctly is important for pedaling efficiency and safety. Fitting a bike involves many factors. However, the basic considerations before buying a bike include frame size, seat height, and…

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Yea lead acid is a great way to cheaply get into ebikes and test new motor/controller combinations. Keep in mind though that your performance will increase when you switch to lithium. It’s easy to do though, as the bike doesn’t care what chemistry it receives, it just sees volts and amps. Good luck!

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.

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 a full list of specifications for the controller but am yet to hear back from them.

Then I took the sense wire labeled B1 and soldered it to the positive terminal of the first parallel group (which also happens to be the same as the negative terminal of the second parallel group, as they are connected together with nickel strip).

Thanks so much for the info, that sounds great and an exciting option! I understand the warranty issue but aside from that, you don’t see any issue than with building a battery of any capacity and just making the discharge cable with an xlr connection to plug into the bike. Would I need a different cable to charge the battery or does it charge via the xlr connection like theirs? Here is one more link with a few more answered questions about their auxiliary battery if you wanted more info. Thanks again, this is really exciting, I just want to make sure I don’t fry anything

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.

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.

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,

26′ rear wheel 48v 1000w hub motor (powerful Motor with hall sensor ) Electric Bike Kit With or Without Battery. 26′ size REAR WHEEL 48V 1000W ELECTRIC BIKE KIT WITH or WITHOUT BATTERY. 48v 1000w brus…

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

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.

When I’m experimenting with some new ebike parts and want to test different battery voltages for different speeds, I often use lead acid batteries because I can try many different voltages using very cheap batteries. Then when the results of my lead acid battery tests show me whether I want to go with 36V or 48V or 60V, for example, I then commit to buying the appropriate lithium battery.

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 have been looking up materials and researching where to buy them for my battery pack. I’ve come to the exact conclusions (and almost the exact same materials) that you write about in this great article. Too bad i didn’t find it earlier… Doh!

If those are new cells then I’m surprised that the voltages aren’t identical. That difference (0.08V) is about the farthest difference I’d want to see between cells. Ideally you should charge that 3.82V cell up a bit more before you connect it in parallel with the others. I’d run tests on all of those cells though with a capacity tester to ensure they are good quality cells though. Genuine cells straight from the factory should all have identical voltages.

That is definitely possible, but keep in mind that the 10 modules you want to connect in series will only need one wire between them. You don’t need to connect the negative and positive of each to the next – you only need a wire from the positive of module 1 to the negative of module 2, then a wire from the positive of module 2 to the negative of module 3 and so on.

Believe it or not, most BMS’s can handle the current from regenerative braking in the discharge mosfets as its rarely more than 5-7A. Some BMS’s (called two wire BMS’s) actually use the same mosfets for charging and discharging. Those inherently should be more than capable of dealing with the load from regen.

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:

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.

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Now the game plan here is to weld batteries for motor scooters groups of 3 cells (or more or less for your pack depending on how much total capacity you want). To weld the cells in parallel, we’ll need to weld the tops and the bottoms of the cells together so all 3 cells share common positive and negative terminals.

HERE ARE 99 GENIUNE LG LGABB41865 18650 2600MAH CELLS. THEY ARE IN MODEM BATTERIES, JUST NEED A FLAT SCREW DRIVER AND PRY THE CASE AT THE SEAM. THEY ARE IN 12V (3S1P) SET UP ALREADY SO YOU CAN SAVE A …

“lithium bike battery +battery for electric scooter”

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

Capacity: 30Ah. output: 71.4V 5A. Lifecycle of single cell: >85% capacity after 700 cycles, > 70% capacity after 800 cycles. (<1C discharge rate and <1C charge rate). Lifecycle: > 85% capacity after 5…

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.

Panasonic and Samsung are the only manufacturers I know of that are producing this chemistry (several other manufacturers buy these and re-label them as their own). Since you would have to buy the bare cells in order to solder together your own pack, I wouldn’t have mentioned these just yet, but…EBAY-seller supowerbattery111 is selling these, and…he will also professionally spot-weld the cells into groups for a small fee, which reduces your pack-building efforts down to about 1/10th of what it would be otherwise. His main business seems to be refurbishing cordless tool battery packs that have worn out.

Regarding the soldering of cells: generally it is not recommended as no matter how you do it, a soldering iron will batteries for motor scooters 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 then put one set of welds on each cell end of the first parallel group, effectively tacking the three nickel strips in place. Then I added another set of welds on each of the negative terminals of the second parallel group. This gave me 6 weld sets, or one weld set for each cell. Lastly, I followed up those single weld sets with another couple welds per cell to ensure good contact and connection.

Lead acid batteries are much larger and heavier than lithium batteries, limiting their placement on ebikes. They almost never come packaged with ebike specific mounting hardware which means that they generally have to go in a bag on the rear rack or in panniers on either side if the rear wheel. Mounting them up high on the rack isn’t a good idea either because it will negatively affect handling. Generally speaking, you want to mount your batteries as low as possible to keep the center of gravity of the ebike lower towards the ground. This will significantly improve your ebike’s handling.

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 of going the opposite way in that regard.

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.

I am just trying to install a battery on a velomini 1 that I traded for. I don’t have a problem using the above battery as a hang on battery, but don’t know if it has the BMS in it or if my current charger would charge it. It is pretty cheap.

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.

One more thing to note about large diameter heat shrink: unless otherwise stated, this stuff usually shrinks about 10% in the long direction, so you’ll want to add a bit extra to the length to account for both overlap and longitudinal shrinkage.

“e-bike battery +battery pack for electric bike”

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Great article! Have ordered everything BUT i have a big problem with the spotwelder. Most homes in europe are limited to 10A and this spotwelder alone drags 15A just to powerupp!!!! I can even start it without blowing both fuses! And when welding it wants 50A-800A which you need a an actual POWERPLANT for!

I placed the first parallel group positive side up, and the second parallel group negative side up. I laid the nickel strips on top of each of the three sets of cells, bridging the positive caps of the first parallel group with the negative terminal of the second parallel group, as shown in the picture.

http://www.aliexpress.com/item/SUNKKO-709A-1500W-welding-machine-small-battery-spot-Welder-with-welding-pen-for-18650-pack-welding/32384498157.html?spm=2114.01020208.3.132.T8tjqL&ws_ab_test=searchweb201556_0,searchweb201602_1_10037_10033_507_10032_10020_10017_10021_10022_10009_10008_10018_101_10019,searchweb201603_1&btsid=06a7c525-fb11-425d-8614-730ff4b43d7e

I should really change that $2 cutoff to more like $2.50, which is more reasonable for quality cells. Basically, the cheapest ‘good’ cells are Samsung 26F cells, which can be had for usually around $2.50 – $2.90 if you are buying in any large quantity, like at least 100. Expect to pay more like $3.00 or so if you’re buying only 40 cells. 26F cells are also limited to 5A discharge though, so you’ve got the same issue as with the NCR18650B cells from Panasonic.

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.

18650 cells, which are used in many different consumer electronics from laptops to power tools, are one of the most common battery cells employed in electric bicycle battery packs. For many years there were only mediocre 18650 cells available, but the demand by power tool makers and even some electric vehicle manufacturers for strong, high quality cells has led to the development of a number of great 18650 options in the last few years.

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.

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, batteries for electric scooters replacement 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.

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.

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.

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.

I am working on a similar project, and was wondering if the BMS’s that you recommended would handle any back EMF from the motor (from regenerative braking, for example.) I see that there are separate leads for charging and discharging, so I’m guessing if current flowed back through the discharge circuit that would be bad. Do you have any recommendations on a BMS (or something different) that would handle this condition?

Assuming the original battery is a li-ion battery and has the same number of cells in series (same voltage), then yes it should charge it. However, looking at the picture of the battery in that listing, I can tell you that is not a picture a 24V 25AH battery. That picture has 6 cells, and a 24V 25AH battery will have something more like 56 cells. That picture looks like a 22V 3AH battery. It could be that they simply used the wrong picture in the listing, though I doubt it as that would be an insanely good price for that size of a battery. but I’d be wary of that offer either way.

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.

As far as dimensions, I prefer to use 0.1 or 0.15 mm thick nickel, and usually use a 7 or 8 mm wide strip. A stronger welder can do thicker strip, but will cost a lot more. If your welder can do 0.15 mm nickel strip then go for it; thicker is always better. If you have thinner strips then that’s fine too, just lay down a couple layers on top of each other when necessary to create connections that can carry more current.

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.

While there are a lot of chemical combinations that can and have been made into useful batteries, in practice there are only four rechargeable types readily available in sizes suitable for ebikes. These are Lead Acid (PbA), Nickel Metal Hydride (NiMH), Nickel Cadmium (NiCad), and Lithium-ion or Lithium Polymer.

“make electric bike -lithium bike battery”

The biggest advantage of lead acid batteries is their price: dirt cheap. Lead acid batteries can be purchased from many different online retailers and local stores. Purchasing SLAs locally helps save on shipping and makes them even cheaper. Many hardware and electronic stores carry them. Even Radioshack has them, though you’ll pay more there.

While it is possible to build packs with any number of cells for just about any voltage, most have standardized in 12V increments, with 24V, 36V, and 48V being most common, and 72V used on occasion. Battery chargers are usually only stocked for these voltages as well.

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.

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.

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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

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.

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But there’s still another issue: now if I just slip my pack inside some shrink wrap tube, I’ll still have exposed ends. This is more or less ok structurally, though it won’t be very water resistant and it will look a bit less professional.

Then I took the sense wire labeled B1 and soldered it to the positive terminal of the first parallel group (which also happens to be the same as the negative terminal of the second parallel group, as they are connected together with nickel strip).

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.

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 batteries for electric scooters replacement if you had any input on how i should move on?

A BMS isn’t necessarily strictly required – it is possible to use the pack as is, without a BMS. But that requires very careful monitoring of the cells of the battery to avoid damaging them or creating a dangerous scenario during charging or discharging. It also requires buying a more complicated and expensive charger that can balance all of the cells individually. It’s much better to go with a BMS unless you have specific reasons to want to monitor your cells by yourself.

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.

I want to use my two 4Ah Ryobi lithium batteries 18volts in series for 36 volts. I have a charger for them , they use 15 batteries each so 30 total, they are $50 each. This seems similar to your 36v build for about $3 each so $90 total, plus a spot welder for $1oo. I want to get a 38v/750 48v/1000w rear motor recommended from your web site from aliexpress. Do you think that these will work for my bicycle?

3. There’s something that I think you might be missing here. The factor that actually limits current draw is the controller, not the motor or the BMS. Those are “rated” for 500w and 15A, respectively, meaning they won’t overheat at those values. But both can physically pass those values if you force them to. It’s the controller that is actually “pulling” the current. So you should check your controller to see what its current limit is. If it is a 15A limit controller, then it won’t physically pull more than 15A. The fact that your battery can technically put out 1200W just means that it has “oomph” than you’re using, and you’re giving it an easy, healthy life. But if you switched to a 50A controller, suddenly you’d be pulling the maximum current that your battery can supply (and probably overheating your motor if you pull that 50A for a long time).

As much as I want to build a pack just for fun and like buying tools like a spot welder I’m afraid of getting crappy cells at a high price. Whatj’s a good cell to charge at 1C for quick turn around and stay at a low price per cell? 36V 12A would be ok, more is a bonus.

The BMS is for 7S, I connect B1+, B2+, B3+, to the negative of the first serie. B4+ is connected to the positive of the first serie, B5+ positive of 2nd serie, B6+ positive of 3rd serie, B7+ positive of 4rd serie.

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.

One term you will frequently come across is the ‘C’ rate of a battery pack. This is a way of normalizing the performance characteristics so that batteries of different capacity are compared on equal terms. Suppose you have an 8 amp-hour pack. Then 1C would be is 8 amps, 2C would be 16 amps, 0.25C would be 2 amps etc. A higher ‘C’ rate of discharge is more demanding on the cells, and often requires specialty high rate batteries.

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

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, we 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.

“enduring cb 10-12 +48 volt scooter battery”

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.

What I would recommend doing is trying to ride again and when the battery cuts off, take it inside and measure the voltage of each parallel group before you try recharging it. Measure straight on the battery. If you find one group that is lower than the rest, it is likely the problem. It might have risen back up to a reasonable voltage with no load, but it can still be lower than the rest.

I am not sure their interests align with mine. I would happily live with 1500 recharge cycles () by which time i would be sick of it anyway) instead of 2000 if I could use 3c in or out when urgently needed.

I am just trying to install a battery on a velomini 1 that I traded for. I don’t have a problem using the above battery as a hang on battery, but don’t know if it has the BMS in it or if my current charger would charge it. It is pretty cheap.

This page is embarrassingly old, referencing chemistries that are completely obsolete, and is due for a rewrite. In the meantime, we recommend checking out our Battery Kits Product Info page for a more current explanation on lithium specific battery packs.

If the 4P10S multi-tube arrangement was for occasional use on long journeys, then it would be reasonable to release all of the cells and to charge them individually or in parallel to about 4V using a normal little single cell charger. Each would then be “top balanced” yes? Then mount them in the tubes, compress and connect the top terminal array and good to go. I’ve still got the quandary about whether to connect them in parallel to the main battery large output terminal.

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.

For a complete write up on LiFePO4 care and trouble shooting read our story here. LiFePO4 cells nominal voltage is generally from 3.0-to 3.2 volts, and generally, lifepo4 is a heavier and less power dense than available LiPo batteries and is not capable of as high of amperage discharge.

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.

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.

Next comes the heat shrink tube. Large diameter heat shrink tube is hard to find, and I got lucky with a big score of different sizes from a Chinese vendor before his supply dried up. Your best bet is to check sites like eBay for short lengths of heat shrink in the size you need.

To wire the BMS, we first need to determine which of the sense wires (the many thin wires) is the first one (destined for the first parallel group). Look for the wires to be numbered on one side the board. Mine is on the backside of the board and I forgot to take a picture of it before installing it, but trust me that I took note of which end the sense wires start on. You don’t want to make a mistake and connect the sense wires starting in the wrong direction.

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 http://huntnbike.com 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.

You’ll see two dots where the 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.

“bike batteries -e-bike battery”

Is there same officially recognized method to come up with C ratings? Ping claims 2C on his LiFePo4 batteries, my Chinese-made “BMC” battery claims 3C. Can they just sort of say whatever they want? How do we determine the “real” C rating?

To reach our intended voltage of 36V, we have to connect a number of 18650 cells in series. Lithium-ion battery cells are nominally rated at 3.6 or 3.7V, meaning to reach 36V nominal, we’ll need 10 cells in series. The industry abbreviation for series is ‘s’, so this pack will be known as a “10S pack” or 10 cells in series for a final pack voltage of 36V.

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…

It is also possible in principle to series connect two 36V batteries to make a 72V setup, but the only battery we have that is intrinsically designed for this is our LiGo modules. With all other batteries, it is essential to use a pass diode across the output of each battery so that when one BMS circuit trips it does not get exposed to a large negative voltage. We have a special series battery cable with this diode built in available here.

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 …

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.

As a side-note, the Boeing 777 Dreamliner battery fire was using LiCo. They wanted a battery that was as light as possible, and as compact as possible. I am not an engineer, but I agree with the statement made by “Tesla” electric car maker Elon Musk, when he said that there was NOT adequate heat insulation between each cell. Better individual cell insulation would prevent a bad cell that was getting hot from heating up the surrounding cells. That is what led to a domino effect. The Tesla cars have a cell cooling system, and the on-board computer can detect and cut-off any cell-group that is getting hot.

As an aside, the 50A-800A you’re talking about is during the output, and that’s at a very low voltage, which is the reason for the high current draw. But that power equals a much lower current on the input end where it draws from the wall outlet.

Great article! Have ordered everything BUT i have a big problem with the spotwelder. Most homes in europe are limited to 10A and this spotwelder alone drags 15A just to powerupp!!!! I can even start it without blowing both fuses! And when welding it wants 50A-800A which you need a an actual POWERPLANT for!

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.

BMS (Battery Management System) watch pictures for all technical information. BMS / PCM (reference)16S-40A. Best upgrade Lithium Battery in most compact size (270 ±2) (150 ±2) (90 ±2 ) mm that will fi…

All the help and knowledge I’ve provided here on EbikeSchool.com is 100% free, and I try to assist readers as much as possible in the comments section of each article. If you want to support this site and help me keep it free (and ad free), consider checking out my ebook and video course on building ebikes.

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.

Lithium electric bike batteries are not cheap, they are not perfect, and they are not readily available. Some OEM’s such as BionX sell a moderately sized lithium e-bike battery pack for $1000 plus. Optibike sells their touring LiPo battery as an add-on accessory for their bike for a gasping $2500. It is surprisingly difficult to find a ready to plug in LiPo battery pack for sale on the internet by any real company.  The reason is simply product liability.

http://www.aliexpress.com/item/SUNKKO-709A-1500W-welding-machine-small-battery-spot-Welder-with-welding-pen-for-18650-pack-welding/32384498157.html?spm=2114.01020208.3.132.T8tjqL&ws_ab_test=searchweb201556_0,searchweb201602_1_10037_10033_507_10032_10020_10017_10021_10022_10009_10008_10018_101_10019,searchweb201603_1&btsid=06a7c525-fb11-425d-8614-730ff4b43d7e

There are two prevalent ideas in pack constructing in these modern days…one is to use larger pouch-like soft cells to construct the pack. The stealthiest battery chemistry by far is LiPo, large cells with power-dense cobalt in the anode chemistry, such as what comes in Hobby King cells. Here is what I mean by “large cell” LiPo. These are soft pouches and large. When you use a pack made of these it will consist of fewer wired together cells than if you use small cylinder cells.

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…

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,

Thanks for your kind words about my article, I’m glad http://electricbikebatterys.com helped! To answer your question, I highly recommend avoiding a custom built charger. While it might be possible to use a DC-DC converter to change the output voltage of your 12V charger, the chances of a problem occurring are too high for my liking. The converter might not be smart enough to adjust the current down once full charge is reached. Technically your BMS should protect your battery from most overcharging scenarios, but if it is overloaded and a component fails, there is nothing to stop your cells from being destroyed.

“build an electric bike battery for electric scooter”

I haven’t seen that exact BMS in the flesh before, so I can’t speak too confidently about it. The description claims it has a balancing feature and so I assume it does, but I’ve also seen BMS that were supposed to have balancing capabilities, but arrived with the balancing components missing from the board.

Gotcha. Can you recommend a manufacturer that sells a two wire version? Maybe I can look around their products and see if they sell any 7S cells, rather than sifting through all the manufacturers on Alibaba. Searches for “2 wire MBS” didn’t yield much. Thanks again for your help with this!

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.

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 am having 36v lithium battery with 4.4 Ah(segway -balancing wheel battery pack ) but i want to convert this battery in to 36v with 9 ah is it possible to add one more 36v lithium 4.4 ah battery with this and i can use as 36v 8.8 ah battery ???? please help me iam not getting lithium battery in india for my e bike

I bought a triangle pack in March 2016…. I reported the issue to EM3ev and they were very concerned. Asked me to do a few tests and it was determined that the battery had a faulty BMS….. They did a replacement pack with upgraded batteries for free….. I …

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 batteries for electric bike balance their packs and constantly monitor the health of their cells.

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.

You can buy LiFePO4 straight from China from Ping Battery. These batteries are a little bulky, but are safe, and will last over 1000 charges. You can also buy ready made Lithium Iron Phoshate (LiFePO4) or Lithium Polymer (LiPo) packs from BMS battery.

Great article! Have ordered everything BUT i have a big problem with the spotwelder. Most homes in europe are limited to 10A and this spotwelder alone drags 15A just to powerupp!!!! I can even start it without blowing both fuses! And when welding it wants 50A-800A which you need a an actual POWERPLANT for!

Why does this formula work? Think about it: heat shrink (unless stated otherwise) usually has a 2:1 shrink ratio, so if I need something with less than twice the circumference (or perimeter rather, since my pack isn’t really a circle) of my pack. Since large diameter heat shrink is quoted in half circumference (flat width) sizes, and I want heat shrink with a circumference of a bit more than the perimeter of my pack, then I know I need the half circumference size to be a bit more than half of my pack’s perimeter, which is equal to the height plus the width of my pack.

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.

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

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.

“electric scooter battery |battery scooters”

For BMS’s, the highest quality ones come from a company called BesTechPower but they are more expensive. I have mostly used BMS’s from AliExpress. I’ve linked to a few examples of BMS’s I’ve used in the article above.

The BMS is for 7S, I connect B1+, B2+, B3+, to the negative of the first serie. B4+ is connected to the positive of the first serie, B5+ positive of 2nd serie, B6+ positive of 3rd serie, B7+ positive of 4rd serie.

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.

As an aside, the 50A-800A you’re talking about is during the output, and that’s at a very low voltage, which is the reason for the high current draw. But that power equals a much lower current on the input end where it draws from the wall outlet.

This pattern continues until we’ve got all 10 parallel groups connected. In my case, you can see that the first and last parallel groups aren’t welded on the top side of the pack. That is because they are the “ends” of the pack, or the main positive and negative terminals of the entire 36V pack.

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.

Battery Model:36V 12Ah. New Lithium 36 volt 12 amp-hour Battery for Electric Bikes (e-bikes) and Scooters. Life cycle:more than 600 cycles. Battery Size (Approximate): 8″ x 3.75″ x 2.75″. Battery Weig…

You may have read recently about the “Bad Girl” of battery chemistries. Its rediculously high C-rate of 20C minimum (you can actually find them with a higher C-rate than this!) means that this is the battery of choice for Electric racers. A proper charging system is expensive, but the batteries themselves were surprisingly cheap when sourced directly from China. What’s the bad part? On rare occasions, they might…CATCH ON FIRE!? 

LiFePO4 is currently widely available for purchase as e-bike packs complete with BMS on ebay and other online merchants. Mostly it is sold by small companies. Also, most of the commercially available e-bikes powered by lithium batteries are using the LiFePO4 chemistry.

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!

Of course, if you go really fast or are pulling an extra load, then this mileage will be worse, like 12-15 wh/km. On the other hand, if you use the motor more sparingly, then you can easily stretch it down to 6-8 wh/km. The table below summarizes the expected range for these different batteries under light, average, and heavy usage paradigms:

First thing is regarding the cells – I have just order some Panasonic 18650PF like yours by chance (I was looking for Samsung). The delivered cells were made and charged in 2014, and the measured voltage now is around 3V (+/- 0.1v). So the voltage is basically the same for all of them but there are old, I think, even thaw never used and stored in a warehouse.

You’ll see two dots where the 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.

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.

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.

A High-performance Motor acheives a top speed of 20-30km/h with a range of 20km means your ebike commute just got easier. Folding style, portable convenient, easy storage. You can lock your bike by ap…

I would not recommend trying to use a 36V charger. The voltage will be way too high and damage either the charger, battery, BMS or all three. Always use a charger that is matched to your pack’s actual charge voltage, which in your case is 22.2V DC.

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.

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 http://electrichuntingbikes.com without any flames.

When you buy your battery, make sure you know what its maximum amp output is. Remember, by multiplying amps and voltage you get the actual current capacity of the battery. For example a 48-volt 25 amp pack can put out 1200 watts.

Offset packing results in a shorter pack because the parallel groups are offset by half a cell, taking up part of the space between the cells of the previous parallel group. However, this results in a somewhat wider pack as the offset parallel groups extend to each side by a quarter of a cell more than they would have in linear packing. Offset packing is handy for times where you need to fit the pack into a shorter area (such as the frame triangle) and don’t care about the width penalty.

Ebikeschool.com has a lot of great info, but I’ve spent countless hours putting even more info, examples, how to’s, reviews, maintenance steps and buying guides into my book and video course. They are some of the most fact-dense and info-rich ebike resources available today. So check them out to see if they can help you with your own ebike!

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Yes, you can upgrade a GIO PB710 with a lithium battery. You just want to make sure your battery is the same voltage as the original lead acid battery and that it can handle the current demanded by the bike’s controller.

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.

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.