I have MPPSolar PCM5048 MPPT which is connected between the solar panels and the batteries. It was working well until yesterday as a sudden it reads negative amps on the battery current. it keeps changing values between (-0.5 to -4 amps at 8 am. while this read should be the same but positive).

Note: I get the negative read on the Battery Current display

MPPT IN and OUT reads:

note: these reads at 8 am while the inverter is off. "no loads on the battery bank"

  • voltage input: between 90 - 100v

  • Voltage output: between 24 - 27v

  • Amps input: between 1 - 3 amps "positive" (depending on day time and battery State of charge percentage).

  • Amps output: between 3 - 5 amps "positive" (again depends on battery SOC and load).

Things I did.

1- I switched off the power inverter to make sure there is no load on the batteries. the result was getting a read between (-6 and -10 amps).

2- I switched off the breaker between the MPPT and the batteries. The result was getting a read between (-18 and -22 amps).

3- I unplugged the batteries and turned off the breaker between the panels and the MPPT and let them for 6 hours. the result was the batteries voltage was 13.1v each. (the batteries are in a good condition)

4- I re-plugged the batteries and switched on the breaker and the problem still the same.


  • What could cause this issue?

  • Is it possible that the mppt gets a faulty read? what to do if it does get a faulty read?

  • Anyway to reset the MPPT other than unplugging it?

  • Could something else other than the MPPT cause this problem?


  • \$\begingroup\$ @winny amps. I edited the post and uploaded the diagram, but looks like there is an error on the link. it does not show the uploaded image. \$\endgroup\$
    – Jaz
    Mar 3, 2020 at 8:30

1 Answer 1


I have found the solution for my case.

Note: This is for my case only.

I just disconnected the earth wire from the power inverter (that's because I found that the MPPT is grounded) and connected the inverter to the battery bank. That seems to solve the problem I had.


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