Can I Modify an Ebike Battery to Work with ESK8

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Hello!

I have recently come into possession of a Luna X1 ebike battery. I took the entire thing apart down to the cells with wires coming off. I haven’t clipped off the existing bms and other circuitry connected to it.

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My ideal would be to replace this existing circuitry with a different bms, remove the extra wiring, repackage the battery, and use it in an esk8.
This Luna battery is apparently a 48V battery with “premium GA cells”. I’m not exactly sure what GA cell means. I also can’t find discharge info on these cells. My biggest question is: is it possible/reasonable to disconnect the existing bms and replace it with an esk8 bms and then hook it to an esc?

Some other questions are: What amount of testing should I do before that point? Should I test each cell block individually? How difficult would it be to test this? What is the strange cell layout (seems to be 6 series of 8 cells in parallel plus a random 4 cell parallel)? What extra materials would I need to finish this battery?

Any help/advice is greatly appreciated!

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I think they’ve high capacity sanyo cells, 10 amp discharge rating. It’s okay to use those cells if your expectations are modest. They wouldn’t typically be a first choice, especially with only 4P, but depending on your needs may well be adequate.

What type of board do you plan to use these in, and how do you intend to install them?

Currently that battery is 13S. Vesc 4 and 6 shouldn’t be used above 12S, so depending on your ESC choice, and enclosure design you may wish to consider 12S. But, doing so would, or at least should mean getting a different BMS and charger.

If you stick to 13S, replacing the BMS is optional as you want to bypass it for the discharge circuit anyway. I always put a fuse in the battery, because if something goes bad, at least I know I’m not going to sprayed with molten metal.

All my builds use recycled cells from escooters also. Rebuilt some old evolves 10s,5p and they were sufficient for short trips. 12S8P would in my opinion make more sense, if you can get two of those bike batteries and have the space / patience / skills to fit them in snug. I’ve been converting evolve GT bamboos to 12S8P, and the fact they’re only 10A cells hasn’t been a problem once there’s 8 in parallel.

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My first esk8 pack with 15 amp rated cells in a 10s 2p configuration, with an ESC rated at 24 battery amps, and whose instructions said use no less than a 30amp battery, was fine, and still is, kinda, on cool or cold days.

As those cells aged, they started getting hotter and hotter during discharge, and voltage sag got worse and worse leading to less torque and range. Then I started to have to baby throttle in an already low power board, and then requiring that I recharge slower to prevent them getting too hot.

Recharging it from the ESC cutout at 3.2 volts per cell, it accepts nearly the same amp hours as when it was new. Meaning its capacity, on paper, is still way over 80% of original, but the pack is now inadequate as I needed to use it.

Many ebike packs that passed ‘capacity testing’ are likely similar.

I built a replacement 10s2p with BAK45D, a ‘60’ amp tabless cell, which are known for much less heating and voltage sag.

My old battery sagged to 36.5v on the first full throttle acceleration, by the time I got to 16mph at a certain distance from garage door.

My new battery sags to 41.2v, and I hit 22 mph in the same exact distance.

Torque and range are way up, and the battery stays so much cooler, that that is no longer a concern.

I want to make use of my old battery, somehow, since it still has good capacity remaining, but returning it to solo esk8 service?.., only in an emergency, and only on cool days.

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So how is this battery configured? I’m confused about the solo group of 4 cells.