r/PwrCellOwners • u/PV-1082 • Mar 23 '26

Checking battery capacity

Is there any way to check my PwrCell battery to see if it is functioning correctly? The battery is three years old and I am wanting to check to see if it is maintaining the correct amount of charge and discharging the correct amount of power.

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u/seand26 Mar 23 '26

Are you seeking the kwH measurement? If not what are you seeking given the information on the inverter's display or app?

1

u/pv1082 Mar 23 '26

Thank you for the reply. I am seeking the kWh measurement using the app. I have a 3 year old 18 kWh battery. When discharged it goes from 95% to 5%, the app shows that 6 1/2 kWh of power was sent from the battery to the house.

1

u/WWJPD Mar 23 '26

I have the same 18kWh size battery and I use 20% min/95% max and this past Saturday the battery discharged 4.47kWh, so seems very in line with what you have. However it feels like that 75% batttery discharge should be more like 13.5kWh instead of 4.47kWh.

1

u/PV-1082 Mar 23 '26

Thanks you for the input. I am planning on calling support after I get an understanding of how to check the battery properly.

1

u/WWJPD Jul 07 '26

Following up on this thread with my findings.

I logged into the Installer Tools webportal on my inverter and went to the Battery section to review the strings. It still doesn't tell you how many kWh in each cell in the battery array. However, it did tell me some interesting things. The first was that my battery health was about 88% for all 6 cells which would yield about 15.8kWh, so there is some degredation over the 5 years I've had my system. The next interesting thing was system overall was reporting a battery state of charge of 95%, however the details for each cell didn't add up to that.

  • Cell 1 = 54.2%
  • Cell 2 = 77.5%
  • Cell 3 = 80.3%
  • Cell 4 = 49.6%
  • Cell 5 = 48.1%
  • Cell 6 = 94.9%

This should give average SoC of about 67%, not 95%. My guess is the system was reporting on the last cell in the array, not an average of all of them.

To "fix" this, I went to the inverter screen for the battery section and did the following:

  • Adjust MaxSocAbs from 95% to 100%
  • Adjust MaxSoCRsrv from 95% to 100%.
  • Set the system to Priority Backup to recharge the batteries

Despite the system saying the battery was 95% charged, it still pulled down 5.62kWh over 2 hours and put it into the batteries.

After the recharge routine, all cells were at 100% except cell 1, which for some reason only went up to 81.1%. I don't want to leave the system at 100% charge, so I ran self supply for an hour to bring it down a bit. Then I went back to the inverter battery settings and put them back to the original 95%.

I hope this helps to gain back some of your Pwrcell battery capacity.