So the other day I was at my local parts store when I noticed they had used half a year old Optima red top on the shelf for sell; aparently a customer returned it saying it was bad, but they tested it and it came up good, so I picked it up for $25!!! Looks brand new, and I put it in my truck to make sure and it works flawlessly; even drove back up to the parts store to have them test it in the truck; it's like a brand new battery! So now I have 2 of the same red tops (had one in the truck to begin with), and I'd like to wire them up to run duel batterys in the truck; furture plans include some more lights, and a mobile air system (and maybe train horns ), so I figure another battery would be great.

So here's the thing, I have a tool box in the back, and it would be awsome to just put it in there (that's were I plan on putting the compressor and tank for the air later on), plus from there all be able to use the battery to jump vehicles, I'll wire in a few 12v outlets for any accessories, and maybe even a power converter. My question is, what's really involved in wiring up a second battery that far away from the original?

I can think of a few main points that I'll have to consider like:
1) wire guage
2) more than likely fuses at both ends of the wire
3) plenty thick rubber grommets where the wires pass through the bed/toolbox.

But the things I'm curious about is will my stock alt be fine with the extra battery added, should I add in in-line cut off selenoid for any reasons like safety, etc...

And the most important thing I was thinking about... the + post of the second battery will just run up to the + post on the original battery, and the - will just ground, right?

Any thoughts and comments from anyone who has done such a thing would be awsome; pics would be even better. It sounds like it would be a great idea to me, but I'd rather have some second opinions before I start anything.

Thanx in advance guys!

 

Try 12voltguy.com he sells a dual battery set up that will take care of everything except the wiring to the alternator and the battery wires you will need to go that far back.

I put my second battery in the same place as the stock one on the oposite side like this

 

You need an isolator so that the batteries are not connected. Otherwise you will drain/ruin one or both of the batteries when the truck is off. Usually people use a 1-2-both-none switch for marine aplications, but others just use a voltage monitor and a solenoid. Essentially, you only want both connected if you are doing something that produces a huge load, like winching for a long period of time. An automatic set up with a solenoid is best if you are going to run auxillary stuff off of one battery. That way, the battery is charged automatically.

I think there are a couple of other things you need too, but I can't remember.

 

ah, I've heard that before too and it completely slipped my mind, thanks!

great setup olharleyman. only issues I would encounter doing that is my current air intake setup...

 

oharleyman,
This is totally off of the battery subject, but was wondering how does the lockers work for you compared to just a stock set up? I saw that you have Aussie lockers. I was contemplating on installing a set. Is it worth the money? Appreciate it. Is it possible to send a pic of your rig?

 

PM him...

 

I ran 1/0 welding cable armored in irrigation tube to two yellowtop batteries under the rear deck. The cables run separately from the battery terminals (the grounds ground together to the frame at the batteries, then a ground wire runs from there to the frame near the motor. I believe in good grounds ) and connect to (are paralleled by) a 250A constant rated 12V solenoid in the engine bay. The solenoid is controlled via a switch on my dash. When picked, the solenoid parallels the batteries and they both charge. When not picked, the primary battery alone supplies voltage.

Another 1/0 cable runs to an insulated stud, where I land all of the + connections such as truck power, winch, accessory feed to aux fuseboxes, etc.

Cables are crimped to large ring terminals and insulated with meltable shrink tube covered with normal shrink tube.

The dash switch is currently fed from ignition +12; I have a switch which will allow IGN pick/ jump/ isolate positions. All I need is time to hook it up.

Works well. No kit needed. 12voltguy.com is, however, an excellent site with good products.

 

phew, he's expensive...

I like the shift knob on that page though, lol

 

wheni did my two batterys for the radio i just put one battery in the back and did power to power and ground to the frame i never used anything else and they were in there for 2 years no problems one never died or over charged but i do have a 110 amp alt to though so that might have helped alot

 

Yeah, see when I think more and more about it, why can't they just be constantly be hooked together. I know late 90s Ford desiles have them hooked that way; correct me if I'm wrong, but their just a 12v system too, and the 2 batteries in those are hardwired together; no isolators or selenoids between them... and besides, if nothing is on and drawing power, how will one battery simply drain the other down? I mean, I understand and know that if one is bad, then it will drain the other, and then ruin it too; but if their both perfectly fine batteries, then I don't see how just wiring them together can creating a problem.

Here's some quick sketches...





sorry, aint got no sophisticated CAD program, MS Paint works just fine if you take your time

just drew the basics; the batteries (one under the hood, one in the box), wiring, alt, starter, etc...

But in it, the orange wires are the original wiring, and the red wiring is what I would add.

I don't see how just doing that be any sort of problem; I mean, I would more than likely add 80 or 100 amp fuses at both batteries...



But doing that would constantly keep both batteries all the way charged, turn it into a monster of a jump start truck when needed with 1440 cold cranking amps total (would probably turn the 22re over at warp speed ), and I wouldn't have to fuss with turning the second battery on and off. Anyone see any huge problems with not using an isolator or anything and just wiring it up this way? Think a stock alt could keep up? Thanks for the input guys!

 

If would basically be this setup, just with longer wires...



Here's another!

 

Ya but you can cut the air tube a bit to fit the battery the tube length is nothing more then a way to get the filter closer to the front for colder air intake

 

Night and day go up hills that I would never have been able to without it tried it a couple different hills I had problems with before the AUSSIE LOCKER now it's like they are not even a 10 degree clime.

 

meh, true... or a 45 degree elbow facing back...

but future plans include a snorkle, so I'd like to leave the intake setup at it's current setup if possible. I'm gunna need a little under-the-hood room when it's custom sorkle make'n time, lol.

 

Night and day go up hills that I would never have been able to without it tried it a couple different hills I had problems with before the AUSSIE LOCKER now it's like they are not even a 10 degree clime.

Here's a couple pics of my truck for ya

 

Just got another idea!

Along with the fuses at each battery, I could also just install selenoids that are hooked to a 3 way switch; comes on with the ignition, constant on override, and constant off override... I would only do this if hardwiring them is really gunna cause major problems, but it's another option for isolating them from each other while the truck's off.

 

A battery isolator is probably cheaper than the set up you mention. Solenoids that are rated for constant use with a battery's full current are pretty expensive. Two of them will out cost a good isolator in most cases.

Edit: Also add in the extra cable (it really adds up with 4 gauge and up) and keeping it as simple as possible will save you money and head aches.

Erich

 

yeah, 4 guage is what I plan on going with

I looked at some 2 gauge today...
1) I think it's overkill for my plans
2) the thickness would make it a pain to work with

 

think of this man car audio ok so they put a cap in the trunk right well whats a cap?? its a very very very very fast acting battery now make it alot slower and hey what do you know its a battery there


battery up front +
-

battery in back +
-

just go + to + (with 100 amp fuses at both ends)
and ground both batterys to the frame thats all i did






and the picture of the truck with the batterys under the truck now thats sick!!!!! but i would never ever drive that in the rain or any where must be a show truck what a same

 

The factory toyota diesels have dual batteries and are just wired together, ++ & --. That is how I did mine and no trouble so far, and I have one small battery and one large battery both located in the bed. I just ran a heavy cable (#4?) and it starts fine, I figure if that'll start a 3.0 turbo diesel it shouldn't have any issue with a 22re.