Big house battery vs Cyrix VSR

[lustyd]

No way. My smart shunt and mppt read the same. The MPPT uses the smart shunts voltage via Bluetooth. Even without, the MPPT voltage is only slightly different due to volt drop. I also have independent voltmeter on the main panel. They read the same battery voltage but independently

Yes, obviously. But what you're seeing is not the actual battery voltage, it's the circuit voltage. If everything is off and no charge present then the battery voltage will eventually settle down, otherwise it's just the voltage on the circuit. As a liveaboard you'll pretty much never have a situation where you can get a real battery voltage because you always have charge or load present.

 

[geem]

Yes, obviously. But what you're seeing is not the actual battery voltage, it's the circuit voltage. If everything is off and no charge present then the battery voltage will eventually settle down, otherwise it's just the voltage on the circuit. As a liveaboard you'll pretty much never have a situation where you can get a real battery voltage because you always have charge or load present.

I don't need to know the at rest voltage. If I get up in the morning and the batteries read 12.7v and they have had loads of fridges, freezer and anchor light all night then everything is good. Once the MPPT is not charging we are in a discharge phase. The real battery voltage will be higher than the voltage at the voltmeter as its seeing discharge.