Hi,
Since installing an MPPT 100/30 charge controller, I've noticed there's a discrepancy between the current reported by the BMV-712 and that of the charge controller.
When getting charged, the battery monitor consistently reports a current significantly higher than what the charger reports outputting.
I've ran a test disconnecting all loads and only leaving the solar charger connected, comparing what the two systems report against a clamp-on ammeter measuring current between the shunt and the battery. I am reading those values:
- Ammeter: 16.85A
- MPPT 100/30: 16.90A
- BMV-712: 25.06A
From this test, it seems the solar charger is correct and the BMV is not. While I was there, I also ran a load test, disconnecting all chargers and comparing the BMV's reported current against the ammeter's:
- Ammeter: -5.43A
- BMV-712: -8.19A
So it looks like the BMV-712 is consistently inflating the actual current, either negative or positive, by about ~1.5x. I don't know when this started, I believe it measured things accurately in the past. On the other hand, the reported voltage is correct when compared against a multimeter.
(I also have pictures from those tests but I can't seem to be allowed to upload them).
I'm not sure what to do here. Do I have a defective unit? Any help appreciated.
Thanks,
A.