Adding Renogy LiFePo4 battery monitor

[IanHall]

So I now have a Renogy 20Amp. DC-DC Charger; a Rover MPPT 20Amp Solar Controller; two 80Ah LiFePo4 batteries in parallel; older WFCO 8955PEC Distribution Centre in my 17 ft. Escape trailer. So I am adding a Renogy battery monitor and I'm a little confused about the wiring.
I plan to connect the neg. terminal to the Shunt; then on the other side of the shunt connect my DC-DC neg. wire and my main neg. ground wire to the frame. Some posted info on internet suggests I have to connect all neg. grounds from everything to the shunt. Is this correct (like the WFCO Dist. Centre) Would appreciate any input. Thanks.

[Brian B-P]

Originally Posted by IanHall

So I am adding a Renogy battery monitor and I'm a little confused about the wiring.
I plan to connect the neg. terminal to the Shunt; then on the other side of the shunt connect my DC-DC neg. wire and my main neg. ground wire to the frame. Some posted info on internet suggests I have to connect all neg. grounds from everything to the shunt. Is this correct (like the WFCO Dist. Centre).

Correct - there must not be a negative wire of any circuit connected between the shunt and the battery negative, because that would mean that the current in that circuit would not be measured by the shunt, so it would not be able to keep track of the net current in and out of the battery.

Strangely, the monitor's manual doesn't make this clear. They seem to just assume that you will understand to connect all negative wires to what they label as P-/C- (location #4) in the diagram. Of course they don't need to connect directly to the shunt terminal.

[IanHall]

Sorry, I wasn’t clear. Yes nothing to be connected to the negative terminal except the parallel neg to battery #2 negative and the connection to the shunt. My question was about the other side of the shunt; can I just have my DC-DC neg and my main neg ground to frame connected, or do I have to bring every Neg ground line to to the P- connector? Thanks for the input.

[rubicon327]

Originally Posted by IanHall

Sorry, I wasn’t clear. Yes nothing to be connected to the negative terminal except the parallel neg to battery #2 negative and the connection to the shunt. My question was about the other side of the shunt; can I just have my DC-DC neg and my main neg ground to frame connected, or do I have to bring every Neg ground line to to the P- connector? Thanks for the input.

When adding a shunt you should not have to do any major rewiring. The shunt connects to the battery negative and all the negative wires that resided on the battery post previously should be landed on the load side of the shunt. You don’t need to move ground wires off the WFCO power center to the shunt. All those loads are covered by the main chassis ground connection you are already making at the shunt.

This is a Victron battery monitor highlighted but the concept of the video by AM Solar might be helpful:
https://m.youtube.com/watch?time_con...ature=emb_logo
*please note as far as batteries they have dual 6V in series which would obviously differ from your two 12V in parallel

[Brian B-P]

As Dave said, you don't need to move anything. That's what I meant by "they don't need to connect directly to the shunt terminal"... where ever negative connections are now is fine, as long as the shunt is in the path between them and the batteries.

[IanHall]

Many thanks... that all makes sense. Ian