I am trying to diagnose/repair an M365 battery problem and I am out of my depth.
The scooter won't charge. When I plug the charger in, the BMS blinks RED four times, then stops - no more red, no blue, nothing. The charger has a steady green light.
The contact tabs on the battery all seem solid and sturdy, but I have not opened up the shrink wrap. The battery is 36V model NE1003-H.
When I check the battery voltage, the readout is NEGATIVE –14.66, even though it's connected red-red, black-black. The DIY videos all show low voltage as an issue, but I have not seen any with NEGATIVE voltage. I don't even know what negative voltage means.
What should/can I do to get this working again? I wish I could just buy an affordable (and authentic) battery pack and swap it out, but at >$100+, that seems wasteful.
Please help! Thanks
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