BBSHD cutting power.

[themartinz]

After riding for a little while and generally while under load (like going up hill), my battery meter on my display with drop to 0% (in red) and my power will cut dramatically. It will still provide power assist, but at about 400watts max. If I turn the display on and off, it will reset and give 100% for a few minutes and the cycle will start over. The motor never completely cuts out.

Does this sound like an overheating issue? I would assume that if I quickly turned the display on and off, he temperature of the battery or controller or whatever would still be hot.

The battery pack is about 3 or 4 years old. Its a 48v pack and seems to charge up fine. I don't know what brand cells are in the pack as it was a custom build put together by someone else. Don't know much about the BMS or any of that. If I ride with pedal assist, this takes a while to occur. If I tax the bike by going full power throttle only up an incline, it will happen much quicker. Just know it didn't always do this, but now its starting.

Any input would be much appreciated.

 

[AHicks]

Low battery charge/voltage might act like that, or high temp, one or the other. Battery may be OK until a large load causes the available voltage to sag to the point where the BMS or controller starts trying to protect the battery.

 

[tomjasz]

Pretty much describes battery sag. A wattmeter would tell the tale.

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