Help locating negative battery wire for new Victron BMV shunt

[gjhathaw]

Looking for help on where to disconnect the negative battery wire to install the Victron BMV shunt. The installation is for a 28' International Serenity RB. I've attached several pictures of what I believe is the area for the install. I do not have an inverter. The area is very challenging to get at for photos/work area (underneath the L-shaped lounge, right where the two lounge sections come together).

Questions:
1) Am I in the right area for the shunt install?
2) From the photos any idea where the black wire from the battery is located at?
3) Do I need to pull out the L-shaped lounge to do the work?

Thanks,

Greg

[vanderwielen]

I'd start with the negative in the battery box. Follow that black wire to a convent mounting location.

[richard5933]

Follow the black negative cable from the battery bank. It will either go to a grounding lug on the chassis or to a negative bus bar. If you have two batteries, you might have one or two negative cables depending on how your battery bank is configured.

There is a larger black cable in the lower portion of the first photo. That'd be one I'd be following.

The basic premise is that the shunt must go between the negative side of your battery bank and everything else. If you have two separate cables going from your batteries to the ground, they must both go to the battery side of the shunt. Then you'll run a cable from the load side of the shunt to where ever the negative cables used to be.

Nothing (absolutely nothing) should be connected between the shunt and the negative side of the battery bank.

Depending on how much work you're planning to do on the electrical system, and how limber you are, will tell you if you need to remove some furniture. I pulled the front sofa from mine because it was pretty easy to do and opened up lots of working room. If you are only installing the shunt and you can manage without pulling furniture, then proceed as is.

[gjhathaw]

Thank you for the feedback. I’ll start chasing the wire from the battery and see if I can miraculously work on it without removing the lounge :-).

[uncle_bob]

Hi

The big reason for starting at the battery is the there *may* be wires attached at that point. Depending on what they go to, they also need to be moved to the "bottom" side of the shunt.

Bob

[GammaDog]

Originally Posted by uncle_bob

Hi

The big reason for starting at the battery is the there *may* be wires attached at that point. Depending on what they go to, they also need to be moved to the "bottom" side of the shunt.

Bob

If your trailer has an inverter, you may actually have two major negative cables (6 ga or larger). In my 2014 as delivered there were two. Those need to be combined to have the shunt record 12v use. Take pics, post them, someone here has solved the same challenge.

[jeffmc306]

gjhathaw, since you don’t have an inverter you likely have only one large negative cable and possibly one for the jack. As everyone else has stated, you want all negative current to run through the shunt.

You can either terminate all on the input side of the shunt or use a busbar to terminate all the negatives and run one to the shunt. That’s what I did and put the shunt in a watertight box on the side of the battery box to minimize the cable length.

Good luck with your installation!
-Jeff

[gjhathaw]

All, wanted to close the thread out. I traced the negative wire coming from the battery thru the floor. I was unsuccessful at seeing the connection of the negative battery cable to a negative busbar because of the L shaped lounge. I simply cut the negative wire near where it passed thru the floor and wired in the shunt. Everything is working.

Thanks all for your help.

Greg