For next weekend I've already got the gears a turning. I'm going to do the dual battery setup I've been wanting to do. What I plan on doing is taking a second soleniod, and mounting it right next to the original one. Then taking all of the accesory power wires off of the original solenoid, and mounting them onto the second soleniod on the second battery post. Then make a jumper between the 2 soleniods and running power from the second battery on the drivers fender. This way the only thing the original battery is running is the starter, and the second battery runs everything else. When I got to start it, the second battery will power the starter soleniod, and the first battery will start it. When I wire it all up, the second soleniod will be open when the key is turned back, but when the key is in the run position the soleniod is closed, alowing the alternator to charge both batteries. Sound right, see any problems with it? I want to change both batteries, but money is only going to permit me to buy one new one, so it'll have to do. Thanks guys.

 

You will need to install a Muti battery isolator so it does not over charge one of the batteries.

Batteries do not discharge, or take a charge at the same rate from the same source. The voltage regulator will keep charging the discharged battery and over charge the second battery that has already reached a full charge in the process. An isolator takes care of this problem.

 

i guess youhave read Billas article on dual batts?

http://www.pirate4x4.com/tech/billav...tery_setup.htm

just another idea to keep in mind! if you plan on going that route i think i can dig up my battery switch i have in the shop somewhere

-cutts-

 

i guess youhave read Billas article on dual batts?

(pyrate) 4x4.com/tech/billavista/dual_battery/my_dual_battery_setup.htm

just another idea to keep in mind! if you plan on going that route i think i can dig up my battery switch i have in the shop somewhere

-cutts-

 

I thought the regulator kept the batt from being over charged? Would I have problems with my setup if I was using 2 identical batteries?

 

Yes, even with two identical batteries.
The battery that is low requiring a charge will keep the voltage regulator "putting out" to charge it, while the battery that has achieved a full charge already, will be over charged in the process.

A isolator eliminates the problem automatically , they do not cost much and are very easy to install.

 

just thinking outloud here, what about a second regulator designated to the second batter?

 

A isolator would be faster, cheaper and easier!

I guess there is no convincing you. I use the same setup for dual batteries for snowplowing and it works without fail. I always have more juice than I can use, (and I do not burn up batteries).

 

Get the isolator. It's a good idea to have any time you have 2 batteries but ESPECIALLY when one is new and the other is old. You can kill that new battery in short time otherwise.

My truck is all pulled apart now but the way mine was set up was the alternator (one wire GM style) fed to the isolator and then to both batteries from there. This allowed them both to charge but kept them seperated so if one died the other didn't. One battery was running all my accessories and the other was hooked to the starter.

I had an additional cable running between them (you could do this at the isolator too) with a high amp solenoid in the middle. The solenoid was normally open but I could close it by flipping a switch. So if my starter battery started getting tired I'd flip the switch and the other battery would feed into the starter. Or if I had a ton of accessories going I could flip the switch and the starter battery would help feed them. But with the switch off they were two totally seperate circuits. Btw, don't try and use a starter solenoid to do this, it'll burn out very soon as they're not meant to handle a constant load like this.

 

Thanks Ivan, I just wanted to explore all my possibilities. Dan, no convincing me? I never said that "no I wont go that way", but I did say I was just thinking out loud, I was just wondering how that would work out.

 

I know a lot of people say you need an isolator. However, since my '83 Olds diesel came with a dual battery setup from the factory, without an isolator, I say you don't need it.

Most importantly, is that you use two of the same kind of batteries. Same manufacturer, same CCA.

I believe Ford also used a dual battery setup exactly as I described with their early 6.9L diesels.

I'm not saying that an isolator is a bad thing; however, I think if you leave the spare battery on charge without using it, you could run into shorter battery life.

btw, if you do try to go with a solenoid to connect both batteries, I'd try to find a contactor from a battery power forklift.. you are not gonna burn that out with just two batteries.

 

Hows a 140 amp for 62$ sound?

 

that would probably be close, as long as it will support a momentary current of about 600 amps (so you would be able to winch or jumpstart your battery). 200 amp would probably be better.

 

ok I've found a 200 amp for 115 to my door. So is this 200 charging amps, or 200 amps could be pulled through it? http://cgi.ebay.com/ebaymotors/200-A...25216394QQrdZ1 what will this do then, will it just keep them both charged up and not allow one to drain the other? How will I isolate the starting battery from the accs. circuit, will I still need a continuous duty high amp relay?

 

Chrono4,

There was supposed to be a smiley face after my comment about “convincing you” but when I noticed it was not there it was to late. Point is if you want the most out of your dual battery setup and you want the batteries to last as long as possible, use a isolator.

Bremen242

Most diesels, the batteries are series wired using 2-6volt batteries making 12 volts, or 2-12volt batteries making 24 volts and would not need a isolator. If not series wired it would have a isolator.