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cottersay 06-20-2021 02:52 PM

Victron BMV 712 Smart battery monitor WTH?
I have the Victron BMV 712 Smart battery monitor (with two 100Ah BattleBorn Lithiums), and the monitor works great when boondocking, but not on shore power. The readouts then make no sense: State of Charge (after a week on shore power): 13% (and dropping); Voltage 14.44V; Current: -2.52A; Power: -36W; Consumed Ah: -186.9Ah.

Anyone have any idea what's up here? :confused:

Thank you!


twinboat 06-20-2021 03:14 PM

You must have a charging negetive on the battery, bypassing the shunt.

ALL negetives must go to shunt. Only wire to battery negetive must be from shunt.

cottersay 06-20-2021 06:48 PM

1 Attachment(s)
Hi twinboat,

I have the setup exactly like this, with the negative out of the shunt going directly to chassis ground:

twinboat 06-20-2021 07:22 PM

And there are no other wires going to the battery negetive posts ?

cottersay 06-20-2021 09:34 PM

No, not a one...

twinboat 06-21-2021 06:19 AM

When you unplug from shore power are the batteries low ?

How are you charging them ?

Persistent 06-21-2021 07:29 AM

It is possible that the Victron unit is defective or needs a setting change.

Other than that, you could post pictures of the battery bank wiring and shunt wiring.

How do you mean, the Victron works OK when boondocking?
Do you charge using a built in generator or a portable generator or solar?
Do you charge multiple times while boondocking?
Do you reset the Victron to 100% when you start boondocking?
Do you charge from your engine alternator? How well does that work?

GPCPL 06-21-2021 11:48 AM

Check that all your settings are correct for your particular setup,and clear the history. A couple of years ago, I had done some work on my battery setup, and wound up getting some strange feedback from my BMV 712. I don't remember the details, but I double checked my settings and cleared my history, and its been good ever since.

cottersay 06-21-2021 01:54 PM

2 Attachment(s)
Thanks, guys!

When I unplug from shore power the batteries are fully charged, even though SOC may read 13% or less.

When I charge the batteries while boondocking with my portable gas generator (floating ground), the 712 monitor has all of the correct readings. I have to charge the batts every day with the generator (at 10,000 feet the genny huffs and puffs inefficiently along). I manually reset the SOC to 100% after a full charge while boondocking. I also charge from my RAM’s alternator at that altitude, because the genny can give out and refuse to start. The RAM method is rather ineffective, but when you absolutely need to pull the awning and slide back in with dead batts, well…

I tried to clear the History on the app, but there is no longer a “clear history” selection under Miscellaneous.

Photo of my battery setup. Shunt is water sealed and hard to get to, but it has no other wires or loads attached to the terminals.

GPCPL 06-21-2021 05:06 PM

Clearing the history on the BMV 712is under 4.2-63 in the manual. Basically, on the meter, press SETUP button for two seconds to access the functions.
Press + or - to browse (#63 is CLEAR HISTORY).
When you get to the desired parameter (63), press SELECT.
Use the SELECT and the + and - buttons to customize. A short beep confirms the setting.
Press SETUP at any time to return to scrolling text, and press again to return to normal mode.
Thats out of the manual, and I hope it helps. I'm pretty sure the only way to clear the history on the 712 is at the monitor itself. Can't clear it from the phone app.

cottersay 06-21-2021 05:57 PM

Thanks GPCPL, that cleared the app's History!

GPCPL 06-21-2021 06:32 PM

Your batteries look fairly new. Did you recently replace them, and did you have the 712 with your old batteries?

cottersay 06-21-2021 09:33 PM

Both the BB batteries and the Victron monitor are only about two years old, so I never experienced the Victron with anything but the BattleBorns...

Persistent 06-22-2021 08:02 AM


Originally Posted by cottersay (Post 5800460)

Photo of my battery setup. Shunt is water sealed and hard to get to, but it has no other wires or loads attached to the terminals.

The negative terminals of the battery are tied to the metal battery box. The wire marked "shunt" it wired to the metal battery box. This connection by passes the shunt to ground. This is why charging is not registered on the Victron.

The wire from the negative terminals of the batteries must go directly to the shunt. It must not "pass go" or connect to anything else.

Get a new battery cable long enough to reach the shunt without connecting to the battery box.

You may need to connect the "house" side of the shunt to ground if it is not already grounded. The ground wire needs to be a big as the battery connecting wires.

I wish you good luck and happy trails ahead!:thumb:

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