No need to spend the $ on an isolator.
I've been running my setup for 2-3 years now w/out a problem.
It's basically the same as the Painless setup.
Just put a large (200amp) relay between the two batteries. Run the relay control wire through a 3 position switch.
Run one wire from the aux battery pos to the switch
Run second wire from any ignition pos (turns on/off with key) to the switch.
This way, in normal position the relay is on (batteries connected) when key is on, and off (disconnected) when key is off (To keep you from draining both batteries together while vehicle is off)
Middle switch positon is relay completely off (batteries disconnect whether ignition on of off)
Switch position #3 is relay completely on (batteries connected whether ignition on or off). This allows you to, essentially, jump the main battery if it goes dead.
I run an Optima Red Top main battery and a Yellow Top aux.
All my accessories, winch, lites, etc run off the aux.
Strongly recommend getting a high amp alternator with any dual battery setup. Otherwise the alternator will be constantly working to keep up.

 

i already have the isolator... freebie, so im going to use it... and isnt the isolator there to charge the weaker of the two batteries so the alternator is not overworked?

 

i already have the isolator... freebie, so im going to use it... and isnt the isolator there to charge the weaker of the two batteries so the alternator is not overworked?

The alternator will still have to be charging two batteries, whether it does it together or one by one, it'll have to work the same amount.
It's like filling two gallons of water with a hose. It takes the same amount of time and work to fill one 2 gallon can as it does two 1 gallon cans.
An isolator also constantly pulls amps to work. In fact, I believe it even continues to take power while the engine is off.

 

Beware of the battery isolator. Make sure it is rated at double the max output of your alternator> I had mine installed for about a year before it internally shorted & caught on fire.:mad3: The fires inspector told me that it was most likley caused by the isolator not being rated high enough. Just my shitty experience.

 

No need to spend the $ on an isolator.
I've been running my setup for 2-3 years now w/out a problem.
It's basically the same as the Painless setup.
Just put a large (200amp) relay between the two batteries. Run the relay control wire through a 3 position switch.
Run one wire from the aux battery pos to the switch
Run second wire from any ignition pos (turns on/off with key) to the switch.
This way, in normal position the relay is on (batteries connected) when key is on, and off (disconnected) when key is off (To keep you from draining both batteries together while vehicle is off)
Middle switch positon is relay completely off (batteries disconnect whether ignition on of off)
Switch position #3 is relay completely on (batteries connected whether ignition on or off). This allows you to, essentially, jump the main battery if it goes dead.
I run an Optima Red Top main battery and a Yellow Top aux.
All my accessories, winch, lites, etc run off the aux.
Strongly recommend getting a high amp alternator with any dual battery setup. Otherwise the alternator will be constantly working to keep up.

Where did you source the 200 amp relay?

 

Where did you source the 200 amp relay?

Got mine off ebay but they're avail all over.
Here are a few from a yahoo search under "200 amp relay"

http://www.darvex.com/miva/merchant.mvc?Screen=PROD&Product_Code=SR200&Product_Count=1
http://www.oznium.com/relay200
http://www.route66supply.com/store/product43.html

 

Or you could go real simple & just get a dual battery switch. See here.

That's what I'll do. Just hard to figure out a place to mount it. Mine will most likely be underhood.

If you want an nice kit that has pretty much all the bugs worked out of it try hellroaring. I've heard nothing but good things about this product.

Later,

Buddy

 

Or you could go real simple & just get a dual battery switch. See here.

That's what I'll do. Just hard to figure out a place to mount it. Mine will most likely be underhood.

If you want an nice kit that has pretty much all the bugs worked out of it try hellroaring. I've heard nothing but good things about this product.

Later,

Buddy

That'll work, however, you'll have to manually pop the hood and flip the switch to disconnect them when you stop.
Then do the same thing to reconnect them when you leave.
Sound like a lot of extra hassle for no reason but hey, that's just me.

The hellroaring piece is just another isolator like he already has.

 

mounting the marine battery switch

I used a marine dual battery switch to hook up my dual battery setup. I installed mine inside my tuffy center console. It there fore acts as a battery cutoff switch that is a theft deterrent when i lock the box. I have soft doors that dont lock at all so this was kinda important to me. It is really simple and easy to do. I used 2 guage welding wire for mine.

 

The hellroaring piece is just another isolator like he already has.

Not quite, it has some sort of module that regulates the flow & does some "auto-thinking" for you, read up a little about it, it's pretty slick.

I used a marine dual battery switch to hook up my dual battery setup. I installed mine inside my tuffy center console. It there fore acts as a battery cutoff switch that is a theft deterrent when i lock the box. I have soft doors that dont lock at all so this was kinda important to me. It is really simple and easy to do. I used 2 guage welding wire for mine.

Nice Idea!! Do you have any pics of the setup? If so, I like to see them. I've also thought about hiding it up under the dash where it's easy for me to switch, but hard to see from the driver's seat. I'd probably also put a fuel-pump kill switch somewhere as well, or maybe this. I figure if I do a couple of these things, (not to mention the rusted, piece of crap, never been washed, beater look), it'll make the jeep a lot harder to try to steal unless they REALLY want it & have a flatbed. That's when the insurance should kick in.

Later,

Buddy

 

Lots of cool ideas here. When I used to park my open, doorless CJ on the waterfront in San Diego for days or weeks at a time, I put in a simple Cole-Hersee battery cutoff switch on the floorboard, and turned it off when i parked it. The first version had a big red key that i took with me. Unless the bandit had the same key, the Jeep wouldn't start. When that switch eventually went out (salt water is hard on electrical stuff) I replaced it with a standard battery switch and a Grant "No Wheel No Steal" system. Along the way I installed a winch on my Jeep, so i added a second battery. To isolate it i used a semiconductor type isolator similar to the Hellroaring system. That isloator worked great for over a decade, but it did drop from 1/4 to 1/2 a volt. Since it got a bit smashed in my cartwheel incident, I have the opportunity to improve the system.
The 200 amp relays should work great. I plan to wire them so that both batteries can be cut off from the Jeep's wiring. With hidden switches to control the relays, the primary wire can be kept short for less voltage drop, and the pair of batteries can be run together when charging, or isolated when dead winching (so the other battery will still start the Jeep).

Mike

 

Pictures

Nice Idea!! Do you have any pics of the setup? If so, I like to see them. I've also thought about hiding it up under the dash where it's easy for me to switch, but hard to see from the driver's seat. I'd probably also put a fuel-pump kill switch somewhere as well, or maybe this. I figure if I do a couple of these things, (not to mention the rusted, piece of crap, never been washed, beater look), it'll make the jeep a lot harder to try to steal unless they REALLY want it & have a flatbed. That's when the insurance should kick in.

Later,

Buddy

Hey Buddy,
I don't have any pictures but i can take some easily enough. What type of pictures do you want to see? The inside of my tuffy box? Some sort of drawing as to where the wires run? Right now it isnt in a dual battery configuration because i am building tube fenders and don't have room for two anymore. Ill be putting the second one in the back. I basically cut a hole to run the wires up through and used a switch much like the one on billavistas area. When i park i just open the box right next to me. Flip the switch and lock it up. It would be a serious PITA to try and figure out what wires to splice and connnect to steal it. Let me know kinda what you want for pictures and i can email them to you.
sokerocks0404@yahoo.com
travis

 

I have the 12 Volt Guys dual battery switch and am very happy with it. Here's a thread: http://www.pirate4x4.com/forum/showthread.php?t=427895

 

Here's a giant picture for you. I have a 200 amp isolator - it's the blue thing with fins you can see sticking up between the fender and the batteries. I have #4 wire from the 165 Amp alt to the center post on the isolator, then a #4 wire to each battery. The top one is aux, bottom just starts the jeep and runs normal lights. The aux runs winch, computer (GPS) inverter, front floods, rear floods, and rock lights. The tray is custom to make room for the giant isolator - it's a foot long.
Enjoy

 

Here's a giant picture for you. I have a 200 amp isolator - it's the blue thing with fins you can see sticking up between the fender and the batteries. I have #4 wire from the 165 Amp alt to the center post on the isolator, then a #4 wire to each battery. The top one is aux, bottom just starts the jeep and runs normal lights. The aux runs winch, computer (GPS) inverter, front floods, rear floods, and rock lights. The tray is custom to make room for the giant isolator - it's a foot long.
Enjoy

Correct me if I am wrong, but I thought the side terminals on Optima Batteries are NOT supposed to take any heavy loads (i.e winch, start, etc).

 

Never heard that - no problems so far.

 

That's true according to Optima. The side terminals are connected to the top with smaller gauge wire and those will fail under unusual high loads like winches,etc. The top terminals will handle this load and are recommended for those applications, regular starter motor loads are acceptable with the side terminals.

 

I have the 12 Volt Guys dual battery switch and am very happy with it. Here's a thread: http://www.pirate4x4.com/forum/showthread.php?t=427895

I run 12 volt guy's , too .

 

I run 12 volt guy's , too .

I just self jump started myself the other day from inside the rig after I left a switch on. Cool!

 

I have the 12 Volt Guys dual battery switch and am very happy with it. Here's a thread: http://www.pirate4x4.com/forum/showthread.php?t=427895

That's the exact system that was described in the 2nd post of this thread.
It allows you to do this:

I just self jump started myself the other day from inside the rig after I left a switch on. Cool!

Don't know what 12 Volt Guy charges for it but Painless' version (same thing) was very pricy for what is essentially a solenoid, switch, cable, and a couple pieces of wire.

 

That's the exact system that was described in the 2nd post of this thread.
It allows you to do this:

Don't know what 12 Volt Guy charges for it but Painless' version (same thing) was very pricy for what is essentially a solenoid, switch, cable, and a couple pieces of wire.

$99 plus $10 shipping http://12voltguy.com/catalog.0.html9.0.html

I thought it was very reasonable.

 

That's true according to Optima. The side terminals are connected to the top with smaller gauge wire and those will fail under unusual high loads like winches,etc. The top terminals will handle this load and are recommended for those applications, regular starter motor loads are acceptable with the side terminals.

Where can I find info on that? I have read everything I could find on Optima's site and saw no mention of side terminal loading issues.

 

$99 plus $10 shipping http://12voltguy.com/catalog.0.html9.0.html

I thought it was very reasonable.

Very.
If I remember right, Painless' system was over $200.

 

For what its worth, I run a dual battery setup in my boat. Granted, I dont have a winch or anything wacky, but its extremely simple. The switch cost $30, it has positions 1, 2, both and off. 1 uses battery one, 2 uses battery 2, both will use both. For a jeep (or other offroad vehicle), it might be a good idea to use a starting battery (high CA for starting and running), and then have the second battery be a deep cycle, which you use for winching, or lights, or whatever else, especially if you plan on using this battery while the vehicle is NOT running.

A starting battery can only be drained so many times before it dies. A deep cycle battery is designed to be drained down and recharged repeatedly.

 

Where can I find info on that? I have read everything I could find on Optima's site and saw no mention of side terminal loading issues.

Quoted from Optima's site: http://www.optimabatteries.com/publish/optima/americas0/en/config/product_info/technology/tips.html

Connecting Batteries Together in Parallel
If your battery application requires more starting power or reserve capacity you can install multiple batteries together in parallel by connecting the like terminals together (positive to positive / negative to negative). Each time you add a battery in parallel you increase the CCA and Reserve Capacity, the voltage remains at 12 volts. For example, two OPTIMA® 34/78's in parallel will provide 1600 CCA and 208 minutes reserve. Three in parallel provides 2400 CCA and 312 minutes of reserve. If you have any questions about multiple battery installations, contact an appropriate automotive service center.


Suggestions for connecting batteries in parallel

* Use batteries of identical make, model, and age.
* Make sure cable gauge is sufficient to handle the higher current flow.
* Prevent cables from shorting (do not allow them to rub against the vehicle body).
* Use only high quality connectors, clean all contacts prior to installation.
* Periodically check all connections for snugness.
* If you are unsure of this procedure, contact your automotive service center.

Battery installation tips

* Ensure that the battery is properly secured in the vehicle or equipment to prevent movement or vibration wear. Do not over tighten the hold down bracket, this can damage the plastic case.
* Connect high amperage accessories such as a winch to the top terminals only. Do NOT use the side terminals.
* Replace any cables and connectors that have corrosion, rust, or other damage.
* Do not install batteries in a non-ventilated or sealed compartment.
* Do not lift or handle the batteries by the terminals.
* Do not over tighten terminal bolts, the following values are recommended:SAE automotive terminal:50-70 inch-lb.Side terminal (3/8" nut):70 inch-lb.Threaded stud terminal:120-180 inch-lb.