BMS 10S TESTING (cut off after riding a few seconds)

[marce002]

Hello

I have 2 10s BMS , and one 8s BMS from electric bike bottles... I need to test them in order to know if they are operative (specially charging with 42,6V 2A AC charger, because does not seem to charge , the led in charger blinks from red/green/red/green etc like an error?)...and when riding they are cuting off after few seconds at not much amps rate (without BMS, the lipo directly connected works fine, so it is bms related problem, at least I will like to use them to charge) ... My question is how can i test them, can I use only for the charging part? connected to the 10s battery , should I expect 4,2v at each cell in the connector? yellow cable is charging, positive go to the battery directly and negative free

I have:

1) Multimeter
2) Lipo Battery 8s and also 10s
3) connectors
4) charger 42,6V


the 8s BMS looks different and more older and complex than the other 2, so will start with the 10s version....

Picture:

 

[circuit]

Have you measured cell voltages? The symptoms sound like you have a faulty cell.

 

[eva-michael]

So without bms, battery pack can be discharge properly? Do you know what's the rated discharge ampere of this BMS and the actually discharge ampere you need? If rated discharge amphere of bms is not enough, that will cause bms protection cut off. Of course, a small connection error will also cause BMS protection.

Double check your wiring to make sure you have not made a mistake. Use a voltage meter and check the voltage between pin(pin from can connector of small balance wires). From the 1st pin to last pin, you will see the voltage increase in
almost equal increments. If you do not, you have made a mistake. Find the mistake and correct it.
Voltage between "little cables(small balance wires)" should be equal as that should be voltage of one cell.
BTW, does this bms have led light as a working signal when corresponding cell is balanced? If yes, a new build battery pack should not have a led which always stay lights.

 

[marce002]

The lipo is ok cell by cell...3.9 per cell x 10s.....from 0 to 39.6v
The connection setup is ok....yellow to input charge negative...blue to output negative to motor.... positive stright to lipo.... the negative lipo to negative black bms ()...should be ok... but both bms do the same: cut of after 10seconds normal riding...

The charge part might also be defective because cannot charge i think.
The charger led blinks attemping to charge...

If cannot find solution or both are burned I will have to recycle the 10s
Lipo with balance plugs 5s x2 and charge via imax b6 rc ...removing the bms..and
Using directly to bike controller ....

What can be wrong? Fets? caps? To charge only , Should I connect just
Balance 10s cable and also the yellow cable to neg of charger...only that.?

 

[marce002]

It must be one lipo cell in the 10s lipo pack.... that makes the LVC to activate in the bms,,,, the problem is how can i detect the bad cell in the lipo 10s array if all of them show arround 3,75v ?? should i deplete the pack riding with no bms attached and recheck?

 

[wesnewell]

If your lipo cells are good, and one is not dropping below lvc, then you're exceeding the max output amperage of the bms and that's what is cutting off. The controller will also shut off if you go below the total voltage LVC in the controller. Do you know the max discharge rating for the bms's?

 

[marce002]

the bms come with this lipo pack inside a typical bike bottle 36v 9mah.... i did not do anything,,,, the only weird thing I've observed is that 4 of the central cells are bigger mah than the others... so they fit inside the bottle diameter....

 

[999zip999]

What are you using it for, with ?

 

[marce002]

350w frontwhel motor hub 36v
controller is also 36v
bike 26"
my weight 74Kg

 

[marce002]

ok, I m flashing new *firmware to my IMAX b6ac charger in order to evaluate "internal resistance" of each lipo cell in the pack.... maybe one is damaged altough all are good volt!



firmware is this: https://github.com/stawel/cheali-charger