Swapping out Batteries

[The Colonel]

I plan to swap out my two 12V Interstates with two 6V AGM, either Duracell or Lifeline. Is there anything I need to be aware of before I begin? I know how to hook up the 6V batteries in series, etc., I believe my battery box is tall enough to handle either AGM I mention so that is not too concerning. I have what looks to be about four positive connections so not sure if new batteries will have enough post or whatever room to hook up. Have others put in a disconnect at the battery? If so is the post mounted switch good enough? Also, this is in preparation for solar install and I plan to put in a battery monitor. The shunt will have to go in there also. I think I may be running out of room or is it my OCD?

[lewster]

Hey Colonel,

You DO have enough room for your batteries, but not necessarily a shunt; especially if its one from Victron (like the BMV-712 model). Plus, that shunt should be placed inside where the elements can't get to it.

You should have enough battery post with the Lifeline GPL-4CT batteries to place all of your positive and negative terminals on the proper posts without any worry.

Let me know if you have any other questions!

Originally Posted by The Colonel

I plan to swap out my two 12V Interstates with two 6V AGM, either Duracell or Lifeline. Is there anything I need to be aware of before I begin? I know how to hook up the 6V batteries in series, etc., I believe my battery box is tall enough to handle either AGM I mention so that is not too concerning. I have what looks to be about four positive connections so not sure if new batteries will have enough post or whatever room to hook up. Have others put in a disconnect at the battery? If so is the post mounted switch good enough? Also, this is in preparation for solar install and I plan to put in a battery monitor. The shunt will have to go in there also. I think I may be running out of room or is it my OCD?

[Adventure.AS]

Originally Posted by lewster

... from Victron (like the BMV-712 model). Plus, that shunt should be placed inside where the elements can't get to it.

Let me know if you have any other questions!

Hey Lewster,

What size cable(s) need to be run for the shunt?

[AirstreamCSH]

From the specs it looks like the shunt is a battery status and history monitor. Would this be of help even if you Don’t have solar but want to boondocks as long as possible or am I reading this wrong?

[Troutboy]

I’ll Lewster correct my ignorance if I’m wrong. First, the shunt is used to measure the amount of charge leaving the battery and with the right monitor, you can see the state of the battery as well as live what the flow in/out is. It can be used in any type of battery system and you don’t need solar.

It’s very important to connect correctly so that all charge goes through the shunt, if you bypass anything, then it won’t register. So typically, you run a line from the negative battery post to one side of the shunt, then you connect all your loads to the other side of the shunt.

The size cable should be the size that you use for the system going to,from, and between the batteries. The heavier the better. These shunts accommodate thick, heavy gage wire.

The wire I used was 2/0.

[lewster]

Yep,

2/0AWG is the smallest cable that I use for a shunt, especially the BMV-712 from Victron.

[billrector]

I installed the BMV-712 just a few weeks ago in my 2017 FC and it is a relatively easy install.

1) I disconnected the black battery cables from the inverter and the neutral bus bar inside the front storage cabinet. These both got terminated with a ring terminal.

2) Mount the shunt in an area where the wires will reach.

3) Put the cables from 1 up above on the battery side of the shunt.

4) Now add a cable to go from the inverter to the load side of the shunt. You will need a ring terminal on this.

5) Now add a cable to go from the neutral bus bar to the load side of the shunt.

6) Move the zamp solar connector black wire to the load side of the shunt.

7) Add a wire from the positive bus bar and connect it on the shunt to power the shunt with 12V.

8) Plug the battery monitor into the shunt with the supplied cable

Done!

By the way, the current inverter cable is 4 AWG and the coach cable is 6 AWG. No need to change these.

[billrector]

Originally Posted by lewster

Yep,

2/0AWG is the smallest cable that I use for a shunt, especially the BMV-712 from Victron.

Lewster, curious why it needs to be so big? In theory, aren't you just putting the shunt in between the existing cables? Those cables are 4 AWG and 6 AWG?

Thanks!

[FishByFly]

If you are just swapping the batteries, why adding the shunt?

[lewster]

Originally Posted by billrector

Lewster, curious why it needs to be so big? In theory, aren't you just putting the shunt in between the existing cables? Those cables are 4 AWG and 6 AWG?

Thanks!

Hey Bill,

I usually add the 2/0 cable for all newer installations. If I'm simply adding the BMV-712 to an Airstream using the available cables then yes, the 6AWG and 4AWG cables will work.

[Troutboy]

Originally Posted by FishByFly

If you are just swapping the batteries, why adding the shunt?

Adding the shunt allows the use of the battery monitor so you can have real time info on the battery state of charge and draw down.

[The Colonel]

Originally Posted by FishByFly

If you are just swapping the batteries, why adding the shunt?

Don’t have to at this time, but plan to add a monitor like a Victron at some point. It may make sense to do so when I swap batteries ahead of a solar install. I’d like to may it as painless as possible, [emoji848]

[The Colonel]

Originally Posted by billrector

I installed the BMV-712 just a few weeks ago in my 2017 FC and it is a relatively easy install.



1) I disconnected the black battery cables from the inverter and the neutral bus bar inside the front storage cabinet. These both got terminated with a ring terminal.



2) Mount the shunt in an area where the wires will reach.



3) Put the cables from 1 up above on the battery side of the shunt.



4) Now add a cable to go from the inverter to the load side of the shunt. You will need a ring terminal on this.



5) Now add a cable to go from the neutral bus bar to the load side of the shunt.



6) Move the zamp solar connector black wire to the load side of the shunt.



7) Add a wire from the positive bus bar and connect it on the shunt to power the shunt with 12V.



8) Plug the battery monitor into the shunt with the supplied cable



Done!



By the way, the current inverter cable is 4 AWG and the coach cable is 6 AWG. No need to change these.

Where physically is your inverter located? I have a 25 FC FB so may not be in same area but my cabling to it goes in the left side of AS and main power cable goes in the right side where power panel, converter are etc.

[billrector]

Originally Posted by The Colonel

Where physically is your inverter located? I have a 25 FC FB so may not be in same area but my cabling to it goes in the left side of AS and main power cable goes in the right side where power panel, converter are etc.

I have a 27' FC FB. My inverter is under the queen bed and on the very left side of the front storage cabinet. All my battery cables come in there...but from both sides of the battery box.

[NoResults]

I am replacing my batteries as one is bad. Is it necessary to extend the positive wire from the Zamp connector and run it inside to the shunt on the Victron or can I leave it on the positive battery terminal.

[The Colonel]

I think you’d run the black wire to the shunt. The positive wire stays connected to the battery. Others can clarify, but if you aren’t going to use the solar port no. But if you ever do you’d probably want that hooked up to shunt for monitoring.

[The Colonel]

Thought I'd take a look at the DC wiring in under my right twin bed. What a mess. I would have thought that the positive buss would have a cover over it. Some of the wiring is extremely short with no wiggle room to move around. Some of the ground wires are tight against the positive buss terminals. I'd think that was not right/safe. just me.....