adding an inverter multi battery

[Alaskaguy]

Hello All, I have just received from an inheritance a 1989 Dodge Xplorer 228 camper van and it has 2 batteries, the 1st is in the engine compartment and the 2nd is under a seat in the mid section, the 1st battery charges like normal from the alternator but the 2nd battery is not charging, the cables on the 2nd battery are much thinner so I'm thinking it was made this way, when I plug the van into the house outlet it starts charging the 2nd battery, can I run the thick battery cables from the 1st battery to the 2nd battery and have the engine charge both without damaging the outlet charging system ?

This van uses a 120A alternator so im thinking it should be strong enough to do it.

Thank you

[markopolo]

I don't see why you couldn't.

But, you need to add an isolator or separator to protect the main starting battery from discharging when the house (auxiliary) battery discharges.
The wiring would be something like this:

[markopolo]

Also, it's a good idea to make sure the second battery is vented to the exterior of the van.

[Alaskaguy]

I don't know much about isolators, are there different types to look for when I buy one, where is a good place to get one ?

Thanks for your help......

[markopolo]

Also add a circuit breaker between the isolator and the auxiliary battery.

Re: isolators

Get one that is rated for the amp output of your alternator.
They'll vary in price. I have a SurePower isolator in my van and would probably replace it with the same if it ever fails.
http://www.cooperindustries.com/cont...isolators.html

This guide is helpful: http://www.cooperindustries.com/content ... lators.pdf

They also make Battery Separators which cost a bit more.

I'd suggest getting someone to do the job if you have any doubts or lack the time and tools needed. It seems like a simple job and maybe it is for a lot of people but I find running, routing, securing, new heavy gauge wire to be a real chore. You'll need to make an entry point in the van for the cables also. If you are running new heavy gauge cables then you'll probably need a real heavy duty crimper. Or you can measure and have the cables made. I get the local Napa to crimp cable ends on. Napa should have isolators. I also see isolators at auto parts stores and RV shops.

My isolator has a 4th terminal and falls under the Group 2 category in the pdf guide above. That's needed for my CS series alternator.
Looks like you can pick from the Group 1 category for Chrysler / Dodge (except Sprinter).

Someone who has installed one in a Dodge might be able to offer some more specific advice here.

[Alaskaguy]

Well now I'm confused, it seems this vehicle already has what looks like an isolator in it, any idea where a fusebox for this might be? I attached a photo of the isolator and where the red wire leads to, looks like it goes to a small black box that says 12v system, might be the switch on the inside of the cab that says 12v system, I have tried it both ways with no luck on charging the secondary battery also in the photos.

Thanks

[olddodgevan]

Check your house (2nd) battery to be sure it is still good. It should charge through the alternator with that set up.

[markopolo]

There are electrical test and isolator test instructions in this pdf: http://www.cooperindustries.com/cont...ST_180012q.pdf

I'm curious about the two wires on the center isolator terminal. Do both go to your alternator? If not, can you trace where the other one lead to?

[Alaskaguy]

ok, I thought I checked the cells on the deep cycle battery (2nd) but I guess I missed it, the cells are indeed dry, this explains it, I put a good battery in place of it and I will test it tomorrow after I drive the van to see if it gets a full charge.

one wire on the center of the isolator is yellow and goes to the wire block on the left of my 2nd picture, it is labeled "Refrigerator", the other wire goes into a taped wire harness and isn't easy to follow but I'm assuming it goes to the alternator.

thank you

[stanw909]

What happened? Did it work?