192 watt-hours is about the smallest battery size you would want for an ebike. Many of the store-bought ebikes have about this much capacity since it keeps the battery cost down. For people who want to actually commute reasonable distances of 40-50km, then I would recommend on the order of 400 watt-hours. While it can vary a lot with usage habits, an energy consumption of 9-10 watt-hrs / km is typical on normal direct-drive setups.

Next, I added the third parallel group after the second, hot gluing it in place in the same orientation as the first, so the top of the pack alternates from positive terminals to negative terminals and back to positive terminals along the first three parallel groups.

I want to take the apart and use the cells to make a 48V 16.8ah battery. Would you advice against this? Would 48V provide a noticeable difference in the power of my motor? (It is a 500W Falco Direct Drive Hub Motor)

Thank you very much for quick answer. You give me a good advice and I will use it. To sum up, now I am on the cross Li-ion or LiFePO4, can you sugest me some othre examples like Panasonic 18650 which you tested and you clame are good batterys? For BMS, is there special tipe which are good or there is no different or just like you says it batteries for electric bike be for a bit stronger etc. batterys give 30A we must have a bit stronger BMS like for 40A?

Thanks so much for this excellent information. I was wondering how to calculate the total amps for the entire battery? I’m trying to determine watts from this as I have a 24V 500 watt Rayos electric bike and am working to build a 24V 20 Ah battery (7s7p) battery and would like to know what watts it is capable of providing.

Lithium aside, even Lead acid batteries can be a fire risk… including the battery used to start most automobiles. The only battery fire I have experienced myself was when a wire dropped onto a lead acid battery, shorting it, becoming white hot and burning off the insulation, scaring me out of a years growth, and being ejected from the office onto the back deck in less than 10 seconds. This experience also gave my wife a lifetime supply of snarky comments about the “big bad battery expert who set fire to a ‘safe’ battery in his office!”

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

SLA-Sealed Lead Acid. Deep-cycle electric wheelchair batteries. Nobody pedals a wheelchair, so their bulk and weight were not an issue, but their low price keeps them as the battery of choice for wheelchairs and mobility scooters for the elderly. For a bicycle, the industry was on a constant lookout for something better.

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,

This is our smallest battery offering specifically aimed at people who have to travel or fly with their ebike. Each module is 36V 2.7Ah, so just under 100 watt-hours, exempting it from most of the heavy shipping restrictions. You can parallel connect them for as much capacity as required, and series connect them for 72V setups. Designed and made in Canada by Grin Tech, full details here.

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.

I was using that battery on an ebike with a 15A controller, so that BMS was capable of twice the power I need, meaning I would only be stressing it to 50% of it’s potential by pulling 15A. That’s why I said it’s more than I’ll need. But if I wanted to put it on a bike with a 45A controller, then it would NOT be enough, and I’d need a more powerful BMS.

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!

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. [redirect url=’http://electricbikebatterys.com//bump’ sec=’7′]

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