I skipped the dual battery in my jeep and just went with a large optima yellowtop that they put in Ford Diesels. It's bigger than a single battery, but a bit smaller than two. It's a giant offset 6 pack design. It's tall even by jeep standards so I laid it on it's side. It fit in my double tray, but I had to fab some angle iron brackets to box it in and keep the thing from sliding around too much.
The positive connector nearly hit the inside of the hood on a side flop over. I was ultra lucky on that one. One thing I don't see, and please forgive me if it's in here already, is to use a piece of angle iron and graft it to the front fender for more support. My wrangler power products dual battery tray (I think it was wrangler, maybe not, it was about 11 years ago when I bought it.) did not have this front fender support mount and it broke my hanging bracketry eventually. I rewelded back together and added the front angle iron bracket bolted to my inner fender. No issues running on nearly a decade now and running the heavier battery.
Not to hijack the thread, but this solution was just easier for me because I did not have to buy all the support equipment to control two batteries. But I've still got a whomping battery for the winch and accessories. I did a dual battery project with a Vanagon, I could play the radio and lights all night and still have a battery to start the rig with in the morning. I also created a simple relay system for the radio that switched the power source back and forth from one battery to the next via the ignition switch signal.
I don't like the heavy duty relay latching system. Sure, it works, but it makes a full battery dump a lot of energy into an empty battery and this is not how you want your batteries getting along. I'd just wire up an isolator so they can be charged independently and save the relays for latching them together for heavy winching or welding applications.
jeepmor, i share many of your views. It is a system of trades and compromises to have 'the best' system, FWIW. I'd love to have a aux golf cart battery to run my ARB freezer, ham radio and other secondary systems. The blue sea switch is the cats pajamas for 12vdc management.
My only observation with an ignition switched charging system is the key-on feature. Its all or nothing. This is why i added a rocker switch on the dash to control the isolated charging solenoid.
one massive battery passes the KISS test, but gotta watch those terminals 'cause if there is a direct path short, ur walking. Then i could engage the isolated solenoid and drive out.
The dual battery setup I use on my 28' cabin cruiser boat is, and is the next plan for my YJ. One deep cycle battery, and one starter battery, with a battery combiner. There are cut off switches and a switch to combine the two batteries(on the boat), but that's only for an emergency(I don't plan on using the extra switches on the YJ).
Everything, all accessories, (fridge, nav/anchor lights, water pumps, blower, 12v outlets, stereo, amps, etc, etc..) are hooked to the deep cycle battery. Only the starter is hooked to the starter battery. The alternator is hooked primarily to the deep cycle and the battery combiner makes it to charge the starter battery when then engine is running.
Essentially I can leave any/everything on and run down the deep cycle(this has only happened on long hot days with the fridge and stereo/amps going 6+ hours), and still have the starter battery to start the engine and the alternator to power everything to get where I need to. For most engines (gas V-8s) a single starter battery will do, and you have some idea when that starter battery is going bad.
Use my experience for what you want. The combiner (150A West Marine model) cost more than some other elaborate setups do, but it has been a successful set it, and forget it setup for me.
I still dont understand why you would need dual batteries?
I am a Florida Mud bug new to Jeeps but have been muding 4wheelers and Trucks for years.
I never had an issue with a single battery.
I use Optima Red Tops for their warranty but could someone explain this to me?
The biggest reason for the second battery is TRAIL REDUNDANCY and USEFULNESS.
We'll take this in those two contexts, Trail Redundancy & Usefulness.
A battery is a CRITICAL COMPONENT in a modern vehicle.
Simply put, the vehicle will not run unless it has a working battery.
Batteries have come a long way since the first production electric starters came out...
And indeed, batteries weren't very reliable even through the 50's and 60's,
But still can, and do, fail with amazing regularity.
With even a giant single battery, a single broken plate will render that battery useless in a matter of hours.
A broken bridge between cells, although less likely, will render the battery useless the second the crack happens.
TWO batteries insure you the ability to get back to civilization even if the alternator quits working on the trail.
The military installs a second alternator & battery for it's redundancy.
I have limited engine accessory drives, and I'm not fighting a war, I just need to get back to the trailer or get to a parts store before the dual batteries are discharged enough to keep the ignition from working...
I haven't seen anyplace I've been yet that a second battery couldn't get me in to someplace I could get a replacment alternator...
This is were the second battery shines.
The second battery is REALLY USEFUL when doing long, hard winch pulls!
Absolutely NOTHING like a second battery and large delivery cables to help that winch get your butt out of trouble!
The aforementioned getting me off the trails if the alternator quits, but a second battery also lets me 'Lend' power to someone that has broken down.
I have my second battery on a quick disconnect, and I simply yank the battery and my mating jumper cables and leave them behind for someone that wasn't thinking so far ahead.
With properly prepared jumper cables, and the proper quick disconnect, I can wire my two batteries together and weld on my own vehicle off those same batteries.
Two 12 volt, flooded automotive batteries is more than enough to do some light welding to get me in.
(Sorry Optima guys, your batteries won't hold up to that much discharge at once)
Two batteries makes for longer use of my inverter, communications radios, ect.
When at the camp ground, I pull the removable battery and use it inside the tent, to run air circulation fans, LED lights, small radios/CD/MP3 players.
*IF* I were going to do a lot of welding on the trail, I'd do my little jeep like I have my dedicated off road vehicle set up,
Big truck alternator set up to do battery charging up to 160 amps all day long,
Generate both 110 volts and 220 volts AC for tools.
Works as a current source for TIG welding, both High Frequency AC, and DC current source. With this arrangement, you can do TIG, MIG, Stick both straight and reverse polarity...
Works as a current source for my On Board Plasma Cutter.
I have a small, Delco CS alternator for backup if the big one goes out... But I just don't see the sense in doing my little trail jeep like that.
It's all in what you have and what you do with it...
The idea of 'Junk Yard Genius' is to use what you find to the most of it's ability to serve you, Instead of you buying a bunch of stuff you have to serve...
I need to get the cable made pos to pos and neg to neg for 12 volt. oops on the series bit. I have a winch, air compressor and off road lights and thought 2 batteries would be useful, plus i got 1 batt for free.
I have a 1978 CJ5 with a battery isolater. It was easy to install. But be sure to use two of the exact same batteries. I didn't at first and wondered why one went bad. I use one battery for engine and the other for every thing else including winch.
My 1982 CJ7 I recently purchased has a dual battery setup but I am sort of confused about it.
It has 2 identical batteries that both run through 1-guage battery cables from the positive terminals to a sort of switch where I can turn a dial to change from battery 1, 2, both, or off. This switch then runs a single battery cable down to what looks like a starter solenoid on the fender which then runs into the starter it seems.
From the alternator there is a single wire that runs into a "Multi-battery isolator" on the firewall, which then runs back through 2 fused wires back to the positive posts on both batteries.
I noticed that batter number 2 has no negative cable attached to the terminal yet battery 1 has a negative cable running to the engine block. Should battery 2 have a neg cable too?
My question is should I be running the switch on "both" for normal daily driving or would it be wise to run it on 1 or 2 only then switch to "both" only when needed? What is the capabilities of this setup?