I have a BMV-700 with bluetooth dongle on a Boat. The shunt is wired to the negative feed of the house bank which is 500Ah of LifePO4. The B2 BMV-700 input is to the AGM Starter battery voltage. This used to work okay with a previous FLA house bank (since replaced). There is a 70/15 MPPT controller connected to the LifePO4 and another MPPT(not Victron) connected to the AGM via their own fuses.
I have tried repeatedly zeroing it with nothing connected (ie loads switched off and MPPT fuse removed). A clamp meter and the LifePO4 BMS both confirm zero amps at this time.
The shunt seems very inaccurate. It swings wildly up to +/-7A when nothing is on. Voltage for both house lifePO4 and starter AGM are fine. Yesterday, in rare UK sun, the MPPT was putting in 12A and the shunt read 0 Amps.
What could confuse the Amp reading? Could there be interference on the data cable OR the shunt B1/B2 cables (both are original length and near other cables).
Do I need a new PCB?
