The battery state does go to zero from time to time, but usually corrects itself within 5 minutes. I noticed it tends to happen when the batteries are near full capacity.I got a red box and no reading on state of charge for aprox 20 min. After that time it came back alive, and continued to show the charge for the day. However cruise control still fails to engage.
I achieved 96% charge after 8 hours of continuous driving. Seemed slow to top up. In previous long days I’d achieved 99% in only a few hours.
I have a feeling it has to do with the direct wiring of the fridge to the Aux battery. I had Drifta’s sparky wire it into the aux with an inline fuse.
From observing my battery monitors on both batteries, I would say the car's SOC reading error range is 3 to 5% plus or minus. So do not worry about 96%. If the charging amps drop to 1-3 amps, the batteries are full, assuming no big current draw.
My fridge is directly wired into the aux battery and I am not seeing this issue, so far.
My rock sliders get fitted today.