30 replies to this topic

[RallyRock]

Hello Again Everyone,

 

Brief background, I am adding a battery monitor so I can better gauge battery life and to avoid draining too low. I am heeding the advice of most here and bought a Victron BMV-712. Haven’t tried to install yet, just planning my wiring before I start. I am having some trouble because most videos and explanations I have found are for batteries wired in parallel but I have two 6v bats wired in series I think. Anyway, I’ve attached some pics with the existing setup and what I think the new setup should be. They are labeled in my own kind of way, sorry I’m not an engineer or knowledgeable of all the standard terminology. 
 

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 3E065AF3-D434-4B72-B848-682BAB4EF4B5.jpeg   98.2K   46 downloads

 

Three things stand out, I’m not sure if what do with W1 or W4 which I think belong to the blue sea charge relay controller. I added my guess as to where they’ll go on the Victron instructions in blue lettering. 
 

next I’ll need to buy a wire, any recommendations on gauge or type of wire?

 

Lastly, do I have the instructions labeled right for my ultimate end goal?

 

thanks in advance for any input. 

 

 

[RallyRock]

To add one more diagram I’m thinking is more pertinent, is the midpoint instruction from Victron. I think in this case all I would need to do is take W3 and W4 from my negative terminal on battery 2 and connect to the load side of the shunt. ThenI just add a new cab,e to connect the neg of battery 2 to the Battery side of the shunt. 

 2EF2965A-5EFB-40F8-BF00-BEC91AFFB168.jpeg   113.02K   42 downloads

 

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[pvstoy]

Yes. You got it. All negative loads go to the shunt the a junper to the negative battery post from shunt

[RallyRock]

Yes. You got it. All negative loads go to the shunt the a junper to the negative battery post from shunt

Nice!  Took me a while but I think labeling the wires helped me. Thanks for checking my logic there. 

[RallyRock]

Yes. You got it. All negative loads go to the shunt the a junper to the negative battery post from shunt

Whelp. I wired it all up and the display doesn’t want to turn on. It appears to be reading a voltage at the power cables into the shunt but can’t get the display to turn on. Checked the fuses too and they seem alright. Any ideas?

[pvstoy]

Pictures of the wiring?

So you took the negative wires off the battery and put it on the shunt. Made a jumper from shunt to negative post on battery.

Have the "B1" on shunt with fuse to positive post on battery.

Meter display wire plugged into shunt.

[pvstoy]

Just do this.

 

Going off your first post image of battery.  Disconnect battery when wiring.

 

Take "W3" & "W4" from the negative post and put on the shunt.

 

Take jumper from other side of shunt to "TC" negative post of battery.

 

Plug in battery monitor cable into shunt.

 

Take thin fused wire with fuse and remove fuse and attach one end to shunt "B1" and other end to "TA" positive post on battery with "W1" & "W2". 

 

Put in fuse.

[RallyRock]

I’ll take some pics in the morning to show what’s what currently. Before I change any of the wiring though I’m going to try a shorter RJ12 cable to see if that wakes up the display. If that doesn’t do the trick I’ll try connecting the wires without the little fuse first to see if that does anything. I did that last step just a little different from what you noted:
 

I took W3 and W4 off of Tc first.
Next i added a new 5ft 6awg cable from Tc to battery side of shunt.

Next I connected W3 and W4 to the load side of shunt.

Lastly, I wired the new positive wires from Td to B2 and the other positive cable from Ta to B1.

When I ran the RJ12 cable to the display I got nothing. Even tried the reset (hold setup and select for 3 secs) and still nada. 

 

Hoping it’s not DOA lol. It was a real pain in the rear working in a cramped battery box. 

[RallyRock]

I also struggled a little with the thin positives going into the shunt. I wonder if they’re not seated all the way. Really was difficult mounting the shunt in an accessible spot. 

[pvstoy]

Disconnect the "B2" cable from the battery to the shunt! That connection is for other applications, like wiring it to you starting battery.

You only want "B1" to the camper battery.