Hi from Germany again!
(relocating my question from another forum topic as suggested),
I am new here, but i am reading in this forum for quite a while.
I purchased 2 36v 20Ah Lifepo4 batteries and connected them in series for 72v in order to use it for a x5304. The controller should work until 48amps.
I have the following problems:
- I was only able to get at most 2000 watt out of the packs, then probably one of the BMS cut off
- Out of the 20 Ah on the first ride I got only 6 Ah out with constant cut offs towards the end at decreasing watts (cut offs at around 400 watts in the end was when I stopped running the vehicle)
- Charging them did not work afterwards
I got the hint that may be some of the cells are out of balance, so i should run them empty on very low power. I did that with one of the packs seperately at 36v and it worked until a total of 14.3 Ah (which seems okay for the first charge)and charging this pack works now fine. BUT the second pack did not do anything, even the braindrain control unit showed nothing and charging is not possible.
Now: Today I let somebody check if there is still voltage with the problem pack. Result: 36.5 volts overall and all 12 cells show voltage. The whole Pack looks fine, the BMS as well and no smell whatsoever...STILL I cannot charge it or run the motor even at the lowest current.
Has anyone an idea what I can do?