36V battery less than a month old looks charged but no power?

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JimmyAndreson   1 µW

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36V battery less than a month old looks charged but no power?

Post by JimmyAndreson » Apr 23 2021 12:34pm

I won't say the brand as I'm working with the seller who has been helpful but...what would cause this? It's on an MTB and it's a pedal-assist bike.

The motor on/off switch control on my handlebar just wouldn't turn on a week ago and they thought it was that...but the replacement did not fix the issue. I checked all wiring, saw that the battery is charged but just for fun, I tested the terminal (I confirmed the pinout from the control board underneath).

If the A/C adapter is plugged in, then the power is displayed as shown. If not...there's no output. Is this normal or did something happen to the battery? Being ridden less than two hours, I'm questioning what would cause this. I didn't drop the bike or had a crash or anything either. I have another e-Bike so not like I'm dying to get this fixed right away but puzzled.

Also, this could be in my head but when I opened the controller underneath the battery, everything seemed okay but there was just a faint smell of something that had fried; but again, it could be me and could be from the factory but it made me wonder if something had shorted.

gobi   10 W

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Re: 36V battery less than a month old looks charged but no power?

Post by gobi » Apr 23 2021 1:28pm

pic pls,
Take voltage at battery, may the BMS tripped, could be bad cell(s)

Do you have a multi meter?

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MadRhino   100 GW

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Re: 36V battery less than a month old looks charged but no power?

Post by MadRhino » Apr 23 2021 2:24pm

Yep. You need a multimeter, and ideally but not mandatory, an ebike tester. First you need to know if there is proper voltage at controller input, then if there is output on the 5v circuit. Those are the minimal conditions, after which you can test controls (switch, throttle, ebrakes), halls and phase output, and all connectors.
Make it fool-proof, and I will make a better fool.

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