SOC

[Franco De Mei]

I have smal question . In wich case SOC is = 0% and battery voltage is 13,50 Vdc

See attachment.

[Dacian Todea (electrodacus)]

When you power the SBMS0 initially the SBMS0 shown will be 49% and at full charge it will be reset to 100%.

That seems like an almost fully charged battery so maybe you did not installed a battery current shunt.

The SOC is calculated based on battery current shunt measurement and integrated over time.

Best guess is that you did not installed a battery current shunt and over time that small -0.051A corresponding to SBMS0 self consumption got the SOC down from initial 49% to 0%

I will need more details if you have a current shunt installed. I can not see anything wrong in the photo. Both charge and discharge is enabled but there is basically zero current flowing in or out of the battery.