Seplos mason boxes flipping zero to 100% cant figure it out.

[ddonq1412]

I now have 2 seplos mason boxes that flip between zero and 100% in seconds. I keep getting monomer low voltage on cells 5 and 6 when i put them on a multimeter they show over 3.3v. I have swapped over a new bms out of the box and its doing the same thing. I am doing cacapity testing on some of the cells to see f there is an issue. all so far seem to drain to 2.8v and over 260 ah. so normal there. when it tries to charge it shoots cells to over 3.7 in seconds and kicks over to 100%. how could i test my pcb boards and wiring harness to get the culcript. I have a set going back on top balance to work this out.

 

[Q-Dog]

That sure sounds like a loose or intermittent connection.

 

[Steve_S]

Check the small connectors with the harness, that plug into the BMS . The connectors can push out and make an intermittent contact causing all sorts of issues. Make sure everything is well seated & all tight.

 

[ddonq1412]

I have 2 boxes doing the same thing. If I was able to get some what of a charge off it I would say it's the cells.