Battery max SOC falling 1% every few days

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stretch193 asked May 7, '24

Battery max SOC falling 1% every few days

Since about mid February the max SOC of our batteries has dropped about 1% every few days. The max SOC shown on the web page is now is 62%. This is an off-grid system with mains connected as a generator.

I asked the installer how to fix this and they said shut down the whole thing and restart and it should reset things. I've done this twice now and still no change.

Inverter is a Victron 48/8,000 Multi Plus ll Inverter/ Charger with 6x Pylontech US3000C 48-volt 3.5kWh Lithium Batteries.

Does anyone know if my batteries are actually loosing capacity or if something needs to be reset so the monitor shows 100% when they are fully charged?

Screen shot from back in Feb when fully charged was 95%:

SOC

95-max.png (57.4 KiB)

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Answer 1 · 2024-05-07T05:49:34Z

nickdb answered · May 07 at 05:49 AM

Perhaps start with the search bar, there are several topics already on this subject.

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Answer 2 · 2024-05-07T06:00:49Z

portsample answered · May 07 at 06:00 AM

I had something similar going on with my system. SOC from Lynx shunt was conflicting with Multiplus inverter produced battery monitor SOC. Unchecking the "enable battery monitor" box on the "General" tab of VEConfig 3, followed by Lynx --> Settings --> Battery Bank --> Synchronized SOC to 100% in the Cerbo resolved this for me. Good luck.

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Answer 3 · 2024-05-10T23:21:59Z

stretch193 answered · May 10 at 11:21 PM

Turns out a couple of days later there was a low voltage alarm from the batteries and after a few minutes of each system restart the batteries would go offline. There seems to be a problem with one of the six batteries. When I remove this from the circuit the system works fine, charging to 100%. Will get the battery sent back for repair/replacement.

Thanks for your replies anyway.

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