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Booster battery for electric scooter

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    Booster battery for electric scooter

    Hi guys, I’m a complete noob and I’m hoping to increase the range of my new Bullet Stealth Carbon II scooter by adding a booster battery. I’ve seen a YouTube video bi Micah at e bike school describing the process. What particularly appealed to me was that he connected the booster battery by simply plugging it into the scooter’s charging port. This is the Youtube link:
    I don’t want to build the booster battery like Micah did but I have spotted one of the same voltage as the built in one on AliExpress which I thought might do the job. Sorry about the long preamble but what do you think about this idea and what problems if any am I likely to encounter? The AliExpress battery has the same number of cells (28) is the same voltage 25.2v, 7s 4p and the same amps at 10.4Ah. I assume I could also charge it with the scooter’s charger.

    You would at least need to match pack voltage before connecting them, that way. There is no way to limit current, so if one battery is at higher voltage, current will surge into the other.

    I'm pretty sure if you just plug one pack into the other ones charge port, at different voltages, you will blow something out. BMS, fuse if present, wires, not sure.

    This sounds sketchy, at best, and probably requires voltage matching to avoid risk of damage or fire.

    Not newbie friendly, I'm my opinion.

    You could more reliably add additional cells in parallel with the main pack, if capable of that kind of thing. Increase from 4p to 5p, for example. But all on the CELL side of the BMS, as intended.
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      Why not just put the 2nd battery in parallel properly using the discharge side? I do that with 2 batts and it works fine. I do separate them and charge separately, but not even sure that's necessary.


        I’ll admit I I skipped through and didn’t watch the whole video, but what I did see looks dangerous and irresponsible. Why would you connect a second battery to the charge port without a way of limiting current? The charging wires, connectors, sometimes even separate bms mosfets, aren’t meant to be used for discharge. You can use a solar charge controller or connect it at the discharge port, there are probably other ways but I don’t know them.