I hope there is someone out there who can help me.  I have just had a 600w inverter installed on my mother's system.  Late this afternoon the inverter panel showed 100 percent.  The only appliance that is running is an A bar fridge, yet an hour later the inverter switched itself off and was showing 76percent.  Is this normal?

Hi Solarconfused, welcome.

Sounds like the SOC is voltage based, which is pretty inaccurate.

Bar fridges draw what, about a 100w, when running, startup peak way more? At least ours do, the 100W.
What battery is it, age?
Inverter make and model?

Thanks for your reply. We have two 100amp gel batteries with two 325w panels, 30amp controller and pure sine wave inverter (will give make shortly). System is 7 months old.  Two months ago the 1000w inverter bombed out and the installer replaced inverter with the 600w, now we experiencing the problem 

Tow thoughts.
One:
I would guess the batts are getting older, therefor the "quick" drop from 100%-76%.

It is not really 76%, as it is volt based SOC, so it could be more like 50% or less.

So when the fridge starts up, the voltage drops to a level that the inverter switches off.

Two:
IF, as the 2 posts above are not clear, IF it is a brand new problem, started the same day the 600va inverter was installed, it can be that the peak startup current of the fridge, exceeds the inverters 600 VA capability.

Edited February 4, 20197 yr by Guest