6S BMS 12A / Power supply 25.5V 300W not charging

Hi all,

Today I made my battery pack ready to test if the pack would charge with my BMS.


  • 12A max charging current
  • 20-26V input

Power supply:

  • 24V adjustable so I had to adjust it to 25.5V
  • Max 300W so the power supply can give enough current

Batteries: 6S2P 222Wh pack

The batteries are nicely balanced due the BMS because when the cells arrived, the voltages of the cells weren’t exactly the same and after connecting the BMS, every cell is 3.72V so that’s a good sign I guess. I connected everything like it should, but the battery is not charging. Also the fan of the power supply is turning but it doesn’t get warm the touch. I guess the problem is the power supply but I don’t know why. Anybody who might know why this isn’t working?

If red is POS , I think you have it wired wrong. The POS leg should be straight through and the NEG leg should connect to the BMS.

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Yeah that’s a bit confusing but the color of the wires which are going to the bms aren’t right, just all red. But I have tested the bms with a bench power supply and there was a current of 5A so I’m sure it’s connected correct.

I guess the problem is the power supply but I don’t know why it isn’t working like the bench power supply…