House Battery vs. Start Battery Location

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SR.GRINGO

SR.GRINGO

Joined
Jun 18, 2004
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Pacific Northwest
So I am in the process of figuring out how to lay everything out with a dual battery system. I have a dedicated start battery--the only wire leaving this battery will be to the starter. The alternator positvie will connect to the the house battery(deep cycle/start)--when full it fills the start battery at a rate of 30 amps. In an emergency I can bridge both batteries via manual switch to start the Cruiser. For simplicity I was thinking of putting the start battery on the passenger side and putting the house battery on the drivers side. Anybody see any problems with this arrangement?

Thanks
 
Depending on what you're trying to accomplish the more common split would be between the stock and the aftermarket sections of the electical system. If you run a dedicated wire only to your starter and completely drained EITHER battery, you wouldn't be able to start your rig. This probably isn't your intention?
 
You will have a much longer run to the starter but that's pretty obvious. What are you using to manage the charging of the "start" battery?

-B-
 
I made my cables and switching heavy enough that it doesn't matter which one I call the -starter-. The batteries are an equal age matched pair, so I keep the switch on -both- in order to keep them both topped off.

In any scenario where I want to -save- a battery, I just switch the system over to one or the other. Which one? Doesn't matter with OO cables.

The disadvantage to my system is it is manual. The advantage to my system is it is manual.

YMMV.
 
Beowulf said:
You will have a much longer run to the starter but that's pretty obvious. What are you using to manage the charging of the "start" battery?

-B-
Click to expand...

Beo--

I have a marine background and have wired several sailboats in the past with charging systems. I have a wholesale account with a marine supply in the states--I was recently home and ended up in the Marine supply store before I could really study mud. Interesting how much common product I ended up with that is the same as Photogod. I ended up with a unit by Balmar www.balmar.net it is called the Digital Duo Charge, Charge flow Regulator. "The duo charge provides an intelligent system for charging at a secondary battery bank -- even if primary and secondary batteries are of different technologies. Four preset programs insure proper charging for Gel, AGM, Standard Flooded, and deep cycle." When the house battery is full it tops off the start battery, then maintains it. Other than a longer start cable it really shouldn't matter--correct? The House would be better on the passenger side but I will have to extend the fusible links....

Grench,

I am wiring my system so that I flip a switch to "all" and I have both batteries to turn over the engine. As far as batteries my deep cycle is a deepcyle/start, I would like to upgrade the dedicated start battery to an AGM in the future. I also plan on using tinned marine cables 2/0.

619TOY,

As mentioned above I have things set up so with a switch so if one battery dies I can start with both batteries. I have a marine switch between the house and start.

Jamisobe,

The thing is about using your start battery as your primary is if you draw it down much you may want to consider a combo deep cyle/start battery---I believe the optima yellow top works this way.

So another idea is to use the start battery for the starter, and connect the fusible links to the start as well--this is how Toyota designed things. Then all the lights, amps, compressor, future winch/fridge can run off the House battery. Hmmmmm........ I get things all layed out with the fuses, dist. bars, relays, then I change my mind again---this is one of those projects I want to take my time on and get it right the first time around. Appreciate all the input.
 
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If it were me I would run an isolator with the dual battery setup and leave one battery for "limp home mode" only... in other words I would only place essentials on that battery (ECU, starter, etc)
 
It doesn't seem like there's much benifit to having the starter on it's own circuit. You still need power to other vehicle systems in order to get the engine running.
 
Odyssey works that way also. I plan on (don't have the Odyssies yet) running two Odyssey PC2150s in the rear in parallel with a red top optima up front for starting and the ECU. The two PC2150s will give me 4300 cranking amps and 370 minutes of reserve capacity with 200 amp hours.

The goal is to be able to run my 2300 watt inverter with the engine off. I want to have HEAT or a fan all night when I am camping. These batteries will take a deep, deep discharge (the inverter shuts off at 10 volts) with no problem and will easily serve to back up the Optima. The seperator insures that I can drain the deep cycles completely [to 10.2 volts] and still start off of the Optima.
 
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SR.GRINGO said:
So another idea is to use the start battery for the starter, and connect the fusible links to the start as well--
Click to expand...

Relocating the fusible links would not be hard.

That sounds like a nifty charger/isolator.

-B-
 
Overkill

SR.GRINGO said:
Grench,
I am wiring my system so that I flip a switch to "all" and I have both batteries to turn over the engine. As far as batteries my deep cycle is a deepcyle/start, I would like to upgrade the dedicated start battery to an AGM in the future. I also plan on using tinned marine cables 2/0.
Click to expand...

Warnings from my project:
OO or 2/0 cables (same thing) are a PITA to work with and are overkill for the application and are stupid expensive in tin coated copper marine cable. Seriously 2ga. cables should be more than adequate for these loads/distances and if I had it to do again, I would not do it with the 2/0.

I got done then realized that I had no circuit protection if one of these monsters were to wear through the insulation and dead short on the body. With all the battery I have sitting behind it, sheet steel could ignite. So, as an afterthought I put in some 300amp fuses at the batteries. Not perfect, but it helps me sleep better.

YMMV
 
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