victron BMV-712 not starting up --should inverter wire also go to shunt?

[emily_in_hawaii]

Hi everyone!



Last night I tried to wire up a Victron BMV-712 battery monitor. I followed the instructions (I think!) but the display never lit up. I have a single 24 volt Victron LifePo4 Battery, going into a Midnight Kid charge controler. I also have a cheap 800watt inverter off Amazon.

The instructions say that the only thing coming off the battery's negative terminal should be the wire going into the BMV shunt. However, the negative wire connecting the battery to the inverter also sits on this terminal. Am I supposed to move this wire onto the shunt also?

Thanks!

 

[MisterSandals]

Am I supposed to move this wire onto the shunt also?

Yes, the current from battery must pass thru shunt before going to inverter. This is only way that the current can be measured (has to go thru measuring device, the shunt).

 

[emily_in_hawaii]

Yes, the current from battery must pass thru shunt before going to inverter. This is only way that the current can be measured (has to go thru measuring device, the shunt).

So you're saying both the wire connecting the battery to the charge controller, AND the wire connecting the battery to the inverter must go through the shunt?

 

[HighDesertOffgrid]

So you're saying both the wire connecting the battery to the charge controller, AND the wire connecting the battery to the inverter must go through the shunt?

Battery (-) wire on one lug of shunt. All charge controllers and inverters (-) on the other one.

 

[sunshine_eggo]

So you're saying both the wire connecting the battery to the charge controller, AND the wire connecting the battery to the inverter must go through the shunt?

ALL current to and from the battery MUST pass through the shunt, or it can't track state of charge.

 

[Rocketman]

Double check your connections, once the shunt is connected to the negative (battery side) and the positive power wire (thin little wire with fuse) is connected to the positive wire and the display is plugged in - the display will operate.

If you have the inverter (or any load) connected directly to the battery negative post - the shunt won’t calculate that into the equation- so the SOC will be off - but the shunt should be running.

 

[emily_in_hawaii]

Double check your connections, once the shunt is connected to the negative (battery side) and the positive power wire (thin little wire with fuse) is connected to the positive wire and the display is plugged in - the display will operate.

If you have the inverter (or any load) connected directly to the battery negative post - the shunt won’t calculate that into the equation- so the SOC will be off - but the shunt should be running.

Hmmm, weird! I get that I need to move the inverter wire to the load side of the shunt, but sounds like the display should still be turning on. I'll see what happens once I move it. Thanks so much!

 

[12vDC]

Hmmm, weird! I get that I need to move the inverter wire to the load side of the shunt, but sounds like the display should still be turning on. I'll see what happens once I move it. Thanks so much!

i think it matters which connection you make to B1 or B2. or maybe either one of those ends of the red cable is loose.

 

[MisterSandals]

but sounds like the display should still be turning on.

Which display? I don’t see anything with a display in your pix.

 

[rhino]

Which display? I don’t see anything with a display in your pix.

That grey cable connected to the shunt will be connected to a small display for the shunt.

 

[Cloroxbottle]

Mandatory connections for a BMV-712:

(1) Black (negative) battery wire from the negative terminal of the battery to the "BATT" side of the shunt. This should be the only connection here.

(2) Everything else to the "LOAD" side of the shunt. This got me when I connected the negative lead from the charger directly to the battery and the shunt could not measure rate/state of charge.

(3) A (much smaller) gauge fused red wire from the B1 port of the shunt to the positive terminal of the battery.

If you're using multiple batteries wired to each other in parallel, the red wire from B1 should go to the positive terminal of the first battery, and the negative battery wire from the BATT side of the shunt to the negative terminal of the last battery in the chain.