I have the following setup in my RV:
- IP22 Charger with 20A
- MPPT 75/15 with two 110Wp Panels attached
- BMV 712
- Liontron 150Ah Battery
The car is currently parked in a large garage and 230V power cable is attached. Two days ago I tokk the car out of the garage and I saw that the BMV 712 reports that only 48% of the battery capacity ist left. As the 230V cable was detached at that time I looked at the status of the MPPT. It was sunny outside an I expected it to charge the battery, but it wasn't. It showed that the battery temp was at -18°C which was definitely wrong. The temperature was around 24°C.
It was the second time that this happened. The first time I saw this -18°C in the IP22 status when it was about 30°C.
After some time the -18°C information disappeard and the MPPT was charging the battery again.
There is no temperature sensor installed on the BMV's shunt.