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Battery for a motorcycle conversion
Hi ladies and gents. A bit of a noob question. I am converting an old motorcycle and just need to try and understand how to build the battery. I am using a 72v 10-12kw hub motor from qs motors it draws approx 140amps continuesly, I need to ride at 5 hours straight mostly highway kms. I was thinking of using the LG 3000mah 20A batteries but would use a less Amps battery for more mah trade off. What size battery do I need to build? And can I get away with joining 3-4 batteries together all with 150A bms? If I go down the 4 separate batteries route do I have to use 4 chargers for each one or tie them all together for 1 big charger? For my application do I need the high drain battery? Cheers for your help
140 Amps continuously?? No man, in that case you would need a battery of 50 kWh which means appr. 5000 of these LG cells. The good news is you won't draw 140 A cont. but only at peak. Still I think you should lower your expectation of a 5 hr drive a lot.
This is the package I was going to get as far as sums I am only guessing as I am new to this game the bike is currently just over 250kgs wet as has a big steel frame so it can take a lot of weight Look what I found on AliExpress
In the aliexpress link, the hub motor can do 130A continuous, max 190A, & peak 260A. That's a lot of juice. And the controller can do 500A for 30 seconds or 200A continuous. Lots of room for growth here.

However, I think you'll find that you will only achieve such high amps at acceleration, like RikH mentions. And then only from a dead stop to full throttle. I would guess that you would be pulling more like about 1/2 that under normal load, even a 1/3 cruising. But I'm not an EV expert, just lots of grains of salt added for sure.

You basically have two paths to take for the batteries. Either go with a 3000mAh LithiumIon with decent amps, around 10A-15A. Or go with Lithium Iron Phosphates (LiFePO4) to get a much bigger punch. They can discharge at higher amps, they have good capacities, cost is about the same, and they are a lot safer in case they get punctured. Take a look at Daromers (DIY Tech & Repairs on YT) builds as he does some really explanations of the various builds. I think he has a full powerwall running on LiFePO4's.

Also check out the section Electric-Bikes-Cars as there are a lot of EV builds in that section of the forum.

And welcome to SLS Smile
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