Bms question

[Matthewrobot]

Hey guys

I have a 48v bike battery.
It’s got 65 cells. So 6 groups of 10 and 1 group of 5.
I found the battery charger wasn’t working.
The output terminals read about 10v
And I’ve plugged in a new charger and it it seems to have charged up a bit and the output terminals now read about 14v
The battery reads about 41v across its main output terminals.

Should I replace the bms or will it start working when the battery is charged up?

Can someone recommend a decent bms with Bluetooth connection so I can see visually what’s going on.

The cells all seem fairly well balanced.

Many thanks

Matt

 

[wturber]

Hey guys

I have a 48v bike battery.
It’s got 65 cells. So 6 groups of 10 and 1 group of 5.
I found the battery charger wasn’t working.
The output terminals read about 10v
And I’ve plugged in a new charger and it it seems to have charged up a bit and the output terminals now read about 14v
The battery reads about 41v across its main output terminals.

Should I replace the bms or will it start working when the battery is charged up?

Can someone recommend a decent bms with Bluetooth connection so I can see visually what’s going on.

The cells all seem fairly well balanced.

Many thanks

Matt

How did you derive that grouping.? All of the groups should have the same number of cells. With 65 cells, you should have 13 series groups of 5 parallel cells - abbreviated 13s 5p. Why 13 groups? 13 * 3.7v = 48.1v ; your battery's nominal voltage.

How is it that you determined that the cells seem "fairly well balanced"? To do that you'd have had to check the voltage of 13 individual groups and find them all at very close to the the same voltage.

Also, it is unclear where you are reading voltages. You mention reading 10v and 14v at different times on "the output terminals". The output terminals of what - the battery or the charger? If you mean the battery, then it makes no sense to me when you say the battery reads 41v across the main output terminals. 41v across the output terminals of a 48v battery would be about right for a battery that is nearly fully depleted but not quite depleted enough to trigger a BMS shutdown.

Maybe you can clarify a bit more about what exactly you are measuring. It sounds to me like you might just have a charger that isn't working correctly and isn't charging up the battery.