www.ColoradoClassicBroncos.com

I'm thinking I would like to run a duel battery set up on my half cab.
Ideally I would like to run the normal engine stuff on one and the other battery would have a LED light bar and a snow plow.
How do I go about this?
Anything that I am not thinking about ?
Would mount the second battery on the opposite side of the original. Any wiring diagrams?

Now that being said I also was wondering if the Alt will charge both of them at the same time ?

My opinion is the point of dual batteries is to have double the capacity. You can get those isolator switches but why? Im running duals and they are just wired in parallel. No switches between them.

I've heard arguments for keeping engine/running battery isolated from everything else in case you accidentally leave something on, you're only draining one battery. also if the engine battery dies, for whatever reason, you can jump start from the secondary battery. most of those arguments come from the overlanding crowd and tend to be folks running fridges and a lot of accessories though.

I would say it depends on how you intend to use the dual batteries. There is probably pros to both arguments of running isolated or in tandem. I added this to my Bronco battery for my popup camper because I didn't want to have the camper battery drain both batteries if I forgot to unplug the connection.

http://www.batterymart.com/p-acc-20092- ... fiEALw_wcB


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cravenbronco wrote:I'm thinking I would like to run a duel battery set up on my half cab.
Ideally I would like to run the normal engine stuff on one and the other battery would have a LED light bar and a snow plow.

Not a bad plan. However I would run everything from the primary battery and keep the secondary completely isolated. This reduces or eliminates the risk of both batteries being run down without your knowledge.

cravenbronco wrote:How do I go about this?
Anything that I am not thinking about ?
Would mount the second battery on the opposite side of the original. Any wiring diagrams?

Mounting the 2nd battery on the drivers side works out well if nothing else is there. I managed to cram both in the stock location, but it took a lot of modifying. The advantage I have is very short cable runs which reduces losses and the chance of a cable rubbing / shorting to the body over time.

My vote is separate the two batteries with an isolator for a couple of reasons:
1) This allows using batteries of mixed age or capacity or style (deep cycle vs starter)
2) One battery is plenty of capacity. You only need capacity to power things when the engine is OFF. The two biggest draws are typically the starter or a winch (or plow pump in your case) If the alternator can't keep up with the running loads, you need a bigger alternator.
3) The secondary battery is handy for jump starting yourself. Using a high-amperage relay (200amp+), you can wire the batteries so jump starting yourself only takes a button push w/o even opening the hood.

I would use a voltage-controlled relay with manual override similar to what Eck posted. This allows the alternator to pump some power into the primary battery (which is needs right after startup) before pushing charge to the secondary.

cravenbronco wrote:Now that being said I also was wondering if the Alt will charge both of them at the same time ?

Yes and no. A small alternator (60amp) can keep both batteries charged if they are close to full, but if they are both run down, then it will have trouble dealing with double the current demands. If your alternator is 95amp+, don't worry about. If you have a 130amp 3G, it's a non-issue.

I did this a while ago in my 4Runner. Most applies to Bronco.

http://www.toyota-4runner.org/engines-s ... setup.html

I used the Sure Power Battery Separator and it is operated flawlessly for 10 years.

http://www.ase-supply.com/Sure_Power_Ba ... _s/154.htm