Dual Battery set-up

[Bachman]

Has anybody put together a dual battery set-up? What stuff did you use? how does it work? Any thing else I should know but don't know yet...

[seapahn]

Here's my setup in the blazer. Not a jeep but it's no different. I am going to do the same in the jeep once money permits (other mods come first). The setup has been very reliable for me and I have actually used it a number of times (about 4 years now).

With the main battery being a deep cycle, I can just let electrical things go until it is fully drained and then flip a switch and get the engine going with the backup battery.

If I could have done anything differently, I would run the negative from the backup battery all the way to the engine block. I just grounded it to the seat belt bolt in the cabin so the battery by itself has a hard time keeping the engine running. But to jump start the main one is no problem.

As far as what to go with, there are many dual battery isolation/combination products out there but I would personally go with a completely solid state one like the Hellroaring module. They have a few better ones out since I got mine. More expensive than simple relay or solenoid based solutions but definitely worth it in terms of reliablitiy and usefullness.

[NAILER341]

i have a dual batery set up in my jeep with one blue top , and one red top optima.
i have used marine grade items to put it together.
http://myjeeprocks.com/forums/showth...trical+upgrade
have a look at this link for some of the parts i used.
the solenoid is a realy wonderful design.
it automatically switches from each battery knowing which needs the charge.
in the event one battery becomes a problem it will protect, and isolate the starting battery.

[Bachman]

Cool, I will have to be getting this started here soon. Thanks..

[USMC 0369]

once again... I'm a Klingon.

My question is: Since I have a 24v power inverter... can I rig it to draw from both batteries for the power inverter, but still keep the Jeep a 12v system? Sounds weird huh?

[seapahn]

I was wondering the same thing a while back here but it turned to more of a winch discussion.

[nagal]

From my foggy memory of electronics I would say no the 24V inverter. To get the 24V Inv. to work, the 2 batteries would have to be wired in series. I believe (and please correct me if I am wrong) the dual battery setup are sort of wired parrallel to allow for easy switching between the 2.

[Old Fart]

From my foggy memory of electronics I would say no the 24V inverter. To get the 24V Inv. to work, the 2 batteries would have to be wired in series. I believe (and please correct me if I am wrong) the dual battery setup are sort of wired parrallel to allow for easy switching between the 2.

'zactly right. Series will double the voltage (24V nominal), parallel doubles the ampacity.

[USMC 0369]

From my foggy memory of electronics I would say no the 24V inverter. To get the 24V Inv. to work, the 2 batteries would have to be wired in series. I believe (and please correct me if I am wrong) the dual battery setup are sort of wired parrallel to allow for easy switching between the 2.

K... lemme throw in more weirdness. I figured out that I didn't understand the difference between "series" and "parallel". So here is what we did in Iraq on the Humvees.

Military humvees run on a 24v system. But most people had 12v power inverters... so the batteries were in "series" but people ran the 12v inverters off of one battery. Can I do that backwards on the Jeep? Have the batteries in "series" and just run the normal stuff off of one for 12v?

Did I mention I know NOTHING about electronics?

[nagal]

What you did in Iraq is know as a Voltage Divider Network (amazing what I can and can not remember). It is very easy to get 12V out of a 24V system, especially when each half of the newtork is already 12V.

I have been typing then deleting here for 10 minutes trying to think/describe all the problems with trying to convert your Jeep to in essence be a 24V system where the electronics only run on 1/2 the system voltage. Its just making me head hurt. Could it be done? Sure. Would it cost more than buying a new 12V inverter? Easily.

[USMC 0369]

Would it cost more than buying a new 12V inverter? Easily.

Oh but Michael! It's a kick ASS inverter I got here.... $2998... and I got is relatively FREE! PLEASE dont ask how, I'll have to plead the 5th!

[nagal]

Well....

we could always hook up 2 batteries in parallel on your (please note the "your") Jeep then hook up the inverter in series to the batteries to see what happens. Just be sure to have plenty of fire extinguishers handy and a tub full of baking soda to roll around in to neturalize battery acid.

[USMC 0369]

Well....

we could always hook up 2 batteries in parallel on your (please note the "your") Jeep then hook up the inverter in series to the batteries to see what happens. Just be sure to have plenty of fire extinguishers handy and a tub full of baking soda to roll around in to neturalize battery acid.

Grrrrrr... This is the kindest way anyone's ever said, "Fine, don't listen to me dork. But I dont wanna be involved!"

Hee hee!!!

I'm still on the suspension build and having issues with that! Electric is WAY down the road!

[NAILER341]

why do you need that much of an inverter?
what do you plan to run off of it?

wiring the batteries to 24v is not a problem, but i wouldnt leave them that way for any length of time.
i do it all the time for the ready welder.
make a pass or 2, and hook it back up to 12v.

[USMC 0369]

why do you need that much of an inverter?
what do you plan to run off of it?

Well lets see, there's the blender, the coffee maker, the microwave, the DVD player, the camp lights, the hair dryer, and of course the big screen TV.

Honestly... I dont stinking know! It's just been my experience when "in the field" with the corps that someone always shows up with the right tool for the job, just nobody has enough power to run it!

This is the inverter that um... fell off a truck. I have the veh model of course.