“diy electric bicycle +bike battery”

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.

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.

I don’t know what you mean by saying your battery is 36W, batteries can’t be measured in watts. The only way to know what power your bike needs is to multiply battery voltage by controller current. If you can’t find a marking on your controller that says what its peak current is, you’d have to measure it with an ammeter, like a clamp on DC ammeter that can measure around the battery wire.

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

The nickel is surprisingly soft, which means you can use an ordinary pair of scissors to cut it. Try not to bend it too much though, as you want it to remain as flat as possible. If you do bend the corners with the scissors, you can easily bend them back down with your finger.

A123 is a brand name of lithium ion phosphate battery used in many EV even full car applications.. A123 cells are known to be of high quality and capable of having high-amp discharge rates with long life expectancy of over 1000 charges. They can provide large amounts of power and have been used in racing applications as well as electric car builds. Chrysler has chosen to use A123 cells in their electric cars.

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.

3. Yes, 18650’s with capacity ratings of 6000 or 8000 mAh are fake. The technology simply doesn’t exist to put that much energy in a cell that size on an economical level. In a few years we might be there, but not right now. Currently, the biggest cells are in the high 3,000 mAh range for 18650’s. 26650’s are larger cells and so those can have higher capacities, but there are many fewer options and variety of 26650 cells, so 18650’s are the common cells used in ebike packs.

If you can’t find the exact same battery to fit in that holder, you could aways open up the area where the controller is and lengthen the wires so they exit the case, then put your own connector there (rated for at least 20A). Then add that same connector to your second battery pack and you’ve got an easy plug and play setup for switching packs with the matching connector.

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i am building a 10s4p 36v 18650 battery pack for my ebike, what gauge silicon wire you recommend for discharge and charge wires, i am using 2.5 amp 42.5v li-ion battery charger bought from ebay(http://www.ebay.com/itm/281639749374?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT), and 10s 36v 30amp bms bought from ebay(http://www.ebay.com/itm/182247900118?_trksid=p2057872.m2749.l2649&ssPageName=STRK%3AMEBIDX%3AIT) and 500w 36v controller.

Now I’m sure you’re all jazzed about building your own battery pack. But just in case, I’m going to leave you with an awesome video featuring battery builder Damian Rene of Madrid, Spain building a very large, very professionally constructed 48V 42AH battery pack from 18650 cells. You can read about how he built this battery here. (Also, note in the video his good use of safety equipment!)

I love this article and I am inspired by the knowledge here, I have a question, I need to build a 72v battery and the one I’m looking at is using 38160 cells, these cells are very expensive so how can I manage this the best using the smaller normal size cells like you’re using! Do I really have to make a battery 20 cells deep to reach this and to bump up the amp hours I would let say go 10 wide for a 30 amp hour right? Pretty close! Big battery but is it feasible or is there a better product

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.

Do you by any chance have some spare parts you can swap in? A spare controller would you let you know if the controller is faulty and tripping early. Another battery would show you if the problem was battery related.

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.

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.

thanks for detail explanation , I was enjoj reading it. Well, I am interesting why did you pick this tipe of battery, I was thinking to use LiFePO4, I know there are usualy 3.2V it is less than 3.6V like here? Also, can you explain me how to calculate max current of battery, it says that you get 8.7Ah, but how much Ampers and what is the power of battery, how many Watts (P = U * I)? Furthermore, without welding, can I do on contact connection, like for example are battery in remote control?

2) Try measuring the voltage of the battery while you plug it in and attempt to power the bike. If you see the voltage drop instantly when you turn on the bike, you’ll know you’ve likely got an issue with weak cells or a poor connection that causes a voltage sag issue.

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 …

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.

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

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

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.

A higher voltage setup therefore needs fewer amp-hours to deliver the same range. So a 24V 8Ah battery can deliver 192 watt-hours, while a 48V 4Ah pack also has 192 watt-hours. Assuming that both batteries are of the same chemistry, then you could expect they would weigh the same, cost the same, and provide the same performance on appropriately designed ebikes (ie, one designed for 24V and the other for 48V).

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

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.

In many situations, especially if you are replacing a battery pack on an existing setup, the voltage is defined by the controller electronics and cannot be readily changed. Otherwise, the voltage determines the maximum speed at which your vehicle will travel, and you have a degree of freedom in selecting the voltage to meet your performance expectations. If you know the volts/rpm for the motor, then it is straightforward to calculate how fast it will go for a given voltage. Select a value that gives an unloaded speed of about 20% greater than your desired cruising speed for best performance.

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!

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 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 batteries for electric scooters replacement start welding. Thanks

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

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

“battery bicycle battery electric scooter”

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. 

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.

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

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.

I also don’t have a spot welder, and for the purpose of building a single 16S2P pack, I’m not sure I want to splurge on that extra $100+. I do have a whole tub of flux and a temperature-controlled soldering iron, so I’ll be attempting to solder the cells instead (extra hot and fast with lots of flux to avoid conducting too much heat into the battery internals from dwell time).

You’ll notice that for my charge wires I used larger diameter wires than the sense wires that came with the BMS. That’s because charging will deliver more current than those sense wires will. Also, you’ll notice the discharge wires (including the B- pad to the negative terminal of the pack) are the thickest wires of all of them, as these will carry the entire power of the whole pack during discharging. I used 16 awg for the charge wires and 12 awg for the discharge wires.

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.

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!

Since most welders have arms like mine, I’ll show you how I did it. I started by hot gluing two parallel groups together in an offset fashion, making sure the ends were opposite (one positive and one negative at each end, as shown in the picture). Then I snipped a pile of nickel strips long enough to bridge just two cells.

LiFePo is 30 to 50% heavier and 10-20% more expensive than LiMn/LiNiCoMn. It’s safe but mainly, it’s got at least double the cycle life of LiMn/LiNiCoMn and seems to have an almost indefinite shelf life.

If you have time, I’d be curious to hear about the pros and cons of this kind of approach. Is the main drawback simply the cumulative size of the plastic housing? Or is there some other limitation to this kind of hardware that makes it unsuitable?

Now that we’ve got all that pesky planning out of the way, let’s get started on the actual battery. Our work space is clear, all our tools are on hand, we’ve got our safety equipment on and we’re ready to go. We’ll begin by preparing our individual 18650 battery cells.

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.

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.

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

Now you’ve got all the info you should need to make your own electric bicycle lithium battery pack. You might still need a few tools, but at least you’ve got the knowledge. Remember to take it slow, batteries for electric scooter everything out in advance and enjoy the project. And don’t forget your safety gear!

I also soldered rather than spot welded and used 1.5mm2 solid core copper between cells, pre-bent to zig-zag shapes on a jig (current is then distributed between them). Offtakes were 4mm2. Soldering technique to minimise heat on the cells was to paint the cells and the wire with flux, load the soldering iron tip with enough solder to make the joint and then, while holding the wire on with the back of a wooden pencil, touch the molten solder to the cell/wire interface and immediately remove the soldering iron tip. This worked really well in terms of soldering quality and the solder cooled very quickly indeed. I cleaned the flux off with a baby wipe and then dried it with some paper kitchen towel.

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.

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.

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.

Do you by any chance have some spare parts you can swap in? A spare controller would you let you know if the controller is faulty and tripping early. Another battery would show you if the problem was battery related.

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

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.

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.

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.

The chain is a very important bicycle part. It is responsible for turning the wheel when a cyclist pedals the bike. Problems with the chain create major riding problems. Chains commonly get dry or rusty,…

THE SPOT WELDING IS ALREADY DONE! I KNOW ALL YOU “DO-IT-YOURSELF” E-BIKE AND POWERWALL BUILDERS OUT THERE ARE LOOKING FOR AFFORDABLE 18650 CELLS. I KNOW THESE AREN’T THE HIGHEST CAPACITY CELLS (1300MA…

Most commercially available 36V packs are around 10Ah, meaning our pack will be just a bit smaller. We could have also gone with a 4p configuration giving us 11.6 Ah, which would have been a slightly bigger and more expensive pack. The final capacity is totally defined by your own needs. Bigger isn’t always better, especially if you’re fitting a battery into tight spaces.

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

“battery powered scooter +lithium ion battery for electric bike”

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

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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?

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!

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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.

For example, suppose you see a 24V 4Ah NiMH battery pack on ebay, that is rated for 1C continuous and 2C max for short times. You might want to get two of these to make a 48V 4Ah battery for your ebike. You calculate that the range will be more than adequate for your short commute to work and back. The problem is that 1C is just 4 amps, while your ebike will probably draw 10-20 amps. If these cells are subject to such discharge rates, then the voltage will sag considerably, leading to slower performance, and the cycle life of the packs will be greatly reduced.

Once you’ve got 2-3 welds on the top of each cell, turn the 3 cells over and do the same thing to the bottom of the 3 cells with a new piece of nickel. Once you’ve completed the bottom welds you’ll have one complete parallel group, ready to go. This is technically a 1S3P battery already (1 cell in series, 3 cells in parallel). That means I’ve just created a 3.6V 8.7Ah battery. Only nine more of these and I’ll have enough to complete my entire pack.

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…

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.

hello, firstly i would like to say that i think this is a brilliant article its really helped me understand a lot more about how this works and how i can use a similar system for my project but i am a little confused and i was hoping to pick your brains….

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Update: it looks like my nickel strips might be pure nickel after all. The salt water appears to have a suspension of brown precipitate which looks and smells like rust. However, after fishing the nickel strip out and rinsing it with water, it still appears to be silver in colour and not rusted:

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.

The bike was more than happy to run and pull me along as long as the throttle was kept very low (<~30%) but as soon the throttle was turned more or I came across a slight gradient uphill the system would cut off (no lights or power). I then have to plug the battery into my charger to 'reset' it before I can then plug it back into my bike and make it work again. I have to keep the throttle low whilst I am riding on the bike before it cuts out but if the wheel is spinning freely in the air then I can max out the throttle and make the motor run at full speed. 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 ... 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… Thank you for the very informative post, and it has helped a lot. I plan on building a battery pack with 20 cells with blocks of 4 in parallel, and then I am going to put those in series to make an 18.5V, 13.6A pack. Sorry if these sounds a little bit foolish, but I am not sure what kind of BMS I should be using. Would I be able to use any BMS or would there be an issue with having extra wires if the BMS can power more batteries in series? Be warned: some less-than-honest vendors try to pass off nickel plated steel for the pure stuff. They often get away with it because it’s nearly impossible to distinguish between to the two with the naked eye. I wrote a whole article on some methods I developed for testing nickel strip to make sure you get what you paid for. Check it out here. It says it is 110 volts (220 are available) but this welder needs a 60 amp circuit (breaker) to work properly so it is not advisable to use at home! anyway, have you found this is a certainty? that you must use a 110 volt (single phase) 60 amp circuit? is this what you are using? have you been having breakers flip when you use your welder on a smaller breaker? (most homes are 20 amp breakers) Or would it just be better to go with their 2 phase (220 volt) 60 amp breaker? I guess I could just pick up another breaker and run it directly from the panel. 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. There are many different types of 18650 cells out there to choose from. I prefer to use name brand cells from companies like Panasonic, Samsung, Sony and LG. These cells have well documented performance characteristics and come from reputable factories with excellent quality control standards. Name brand 18650’s cost a bit more, but trust me, they are worth it. A great entry-level cell is the Samsung ICR18650-26F cell. These 2,600 mAh cells should cost somewhere around $3-$4 in any decent quantity and can handle up to 2C continuous discharge (5.2 A continuous per cell). I get my Samsung 26F cells from Aliexpress, usually from this seller but sometimes I’ve seen a better price here. 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. Lithium chemistry is considerably more expensive than the “old school” lead acid chemistry. If you are buying a battery pack or a bike that already has a battery pack, be familiar with the chemistry that you’re buying. For example, its hard to find a good e-bike for under a thousand dollars with a decent-sized lithium pack. Lithium is pricey. Be realistic in your expectations when e-bike shopping on how much the electric bike will cost compared to what kind of range, performance, and life expectancy you will get out of a lithium battery pack. Absolutely, a relay is the way to go. Use the keyswitch you bought to activate the relay, then the relay will carry the heavy current flowing through your battery’s positive discharge wire. Alternatively, you could install 9 or 10 of these switches in parallel. Just make sure you mark your keys accordingly 😉 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.  NCA…LiNiCoAl / Lithium Nickel Cobalt Aluminum (sometimes called NCR) The battery chemistry research industry is still driven by the HUGE global sales of laptop computers, cellphones, and cordless tools. Mass production has made the 18650 format the best cost per volume cell. The 18650 number means that it is 18mm in diameter, 65mm long, and the zero means it is a cylinder instead of a flat foil packet. (the 18650 is roughly the size of an adult male thumb) [edit: in 2014, Tesla electric cars are now using Panasonic NCA batteries] Most commercially available 36V packs are around 10Ah, meaning our pack will be just a bit smaller. We could have also gone with a 4p configuration giving us 11.6 Ah, which would have been a slightly bigger and more expensive pack. The final capacity is totally defined by your own needs. Bigger isn’t always better, especially if you’re fitting a battery into tight spaces. In many situations, especially if you are replacing a battery pack on an existing setup, the voltage is defined by the controller electronics and cannot be readily changed. Otherwise, the voltage determines the maximum speed at which your vehicle will travel, and you have a degree of freedom in selecting the voltage to meet your performance expectations. If you know the volts/rpm for the motor, then it is straightforward to calculate how fast it will go for a given voltage. Select a value that gives an unloaded speed of about 20% greater than your desired cruising speed for best performance. 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. Have a plan on where you are going to charge your bike before settling on a battery chemistry. If you live in a crowded apartment building and the only place you have to charge is in your living room floor, you may want to decide against any of these lithium technologies. Lithium batteries (with the exception of RC LiPos) last much longer than lead acid batteries. LiPo batteries are usually only rated for a few hundred charge cycles but LiFePO4 batteries keep going after thousands of charge cycles. Every manufacturer rates their batteries differently, but most LiFePO4 ebike batteries will be rated for between 1,500 to 2,200 charge cycles. 3. Yes, 18650’s with capacity ratings of 6000 or 8000 mAh are fake. The technology simply doesn’t exist to put that much energy in a cell that size on an economical level. In a few years we might be there, but not right now. Currently, the biggest cells are in the high 3,000 mAh range for 18650’s. 26650’s are larger cells and so those can have higher capacities, but there are many fewer options and variety of 26650 cells, so 18650’s are the common cells used in ebike packs. Lithium batteries are also small enough to allow you to place your batteries pretty much anywhere on your bike. This is especially true for people who want to assemble their own pack or use heat shrink wrapped lithium batteries instead of hard case lithium batteries with prefabricated bicycle frame mounts. This can help spread the weight around or hide the batteries to make a stealthier bike. 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 https://en.wikipedia.org/wiki/Electric_bikes 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. [redirect url='http://bestelectricbikebattery.com//bump' sec='7']