question

jabrodsky avatar image
jabrodsky asked

BMV 712 giving correct data?

I have two 6 volt AGM batteries hooked up in series to yield a system load of 12 volts. Due to the separate locations of the batteries, my shunt wire (negative) and the positive draw to power the monitor all come off of the same battery.

Question: although the monitor shows system voltage is 6 volts, are the other metrics, such as power, state of charge, etc, correct? If I change the positive draw from the near battery to the far battery, will any other metrics be affected?

installation
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3 Answers
JohnC avatar image
JohnC answered ·

The wire from the shunt that goes to the +ve batt terminal should be relocated to the other batt's +ve terminal (the one labelled 'RV loads').

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brassmonkey001 avatar image
brassmonkey001 answered ·

Looks to me like you are only monitoring that one battery, like as if you dropped a multimeter across it, it would only show 6v. You need to connect your positive shunt wire to the other battery's positive terminal, that should give you a true reading of what is happening across both batteries.

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Justin Cook avatar image
Justin Cook answered ·

@Jabrodsky, hmmm nope, something is amiss if your batteries are connected in series for 12v but the BMV is showing 6v system voltage. Please post some pics showing your connections and your battery setup, if possible, so that we can troubleshoot this, because it definitely is affecting the BMV's calculations if it can't tell the system voltage.

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jabrodsky avatar image jabrodsky commented ·

It’s tough to photo, so let me try to put this schematic out there. I put a meter on the shunt power, and yes, it’s reading 6 volts. And I checked my house system at the fuse block. 12 volts.

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