Mangosteeen m1 cutting out power.

[sanel_net]

Hi guys and girls
I've just bought a Mangosteeen M1 2000w, 60V 20Ah battery chopper. It has only few miles on the clock. Out of warranty. Haven't been charged in months (battery was still at full), driven it 40kms and it started cutting out. It takes away the throttle and applies regen, like I'm holding a brake (I'm not). After I stop it runs fine again. Than it started shutting off the screen (like is completely dead), after unplugging battery it comes alive, drives normally for a period of time. After that it cut out, screen off, even battery unplugging not helping anymore (all this happened in one hour time), when I connected charger it came alive again. Put it on a lift, throttle all the way, it ran for few minutes and suddenly dies (battery was still at 52V). I have checked all the wire connections and mechanical sfuff, all brand new and tightened. Do you think it's the battery or the controller problem? I'm confused by that first few times when it cut out.... Screen was still on, and the regen was braking hard, battery would not do that.

 

[j bjork]

the times it cut out so you had to unplug the battery for it to start again sure sounds like the bms turned off for whatever reason anyway. The other times it is harder to say if it is battery or something else.

 

[sanel_net]

the times it cut out so you had to unplug the battery for it to start again sure sounds like the bms turned off for whatever reason anyway. The other times it is harder to say if it is battery or something else.

Thanks.
I've been told by the battery repair guy, that I should cycle the battery few times and it will fix any unbalanced cells, if there is any.

 

[amberwolf]

Haven't been charged in months (battery was still at full), driven it 40kms and it started cutting out.

If power actually turns off, that almost always means that at least some of the cells are not able to handle the load the system puts on it, and the BMS is cutting off power to protect the cells from damage that can lead to a fire. Defeating that safety by cycling power to reset the BMS just gives more chances for such damage to happen.

The cells could have been defective from the factory, or failed while sitting at full charge, or somewhere between those points. But my guess is it was bad to start with, and was the reason it sat unused (regardless of what the seller told you, because...people).

The cells may have high resistance, or low capacity, or both, to cause this specific type of problem.

I've been told by the battery repair guy, that I should cycle the battery few times and it will fix any unbalanced cells, if there is any.

Nothing will actually fix an imbalance other than replacing all the cells with matched cells, that have identical properties to each ohter.

The reason imbalance happens is because the cells are physically different from each other, so they charge and discharge differently, and end up at different voltages.

A BMS can help minimize the effect this has, up to a point, by forcing them all to the same voltage at end of charge, if you leave it on the charger long enough (until the charger stops turning on and off, and stays off).

That can take hours for a minor imbalance, days for a serious one, and weeks for an essentially failed battery whose cells are wildly mismatched in capacity, resistance, etc.

Cycling the battery (charging and discharging it repeatedly) doesn't do anyting to rebalance it, it actually makes such a problem worse.