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Dual Batteries?


Jibs
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Im also thinking of doing this, i have three electric air pumps i am going to install, along with 3 sets of lights and the stereo etc...

 

Will the 2nd battery help me while the motor is running as well? Or is it only beneficial when the car is off?

 

And yeah, i wouldnt attempt this mod without doing the GM or at least the XT6 alt mod.

 

-Brian

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Yes definatly an excellent link. I think i'll just wire all my accessories from the 2nd battery, and use an isolator.

 

-Brian

 

right. just get the isolator and another battery and wire it up as the directions say. you dont need a bigger alternator, the stocker does fine. ive got dual batteries in the battlewagon and i can run all 8 lights, sterio, full heater and still have enough juice to plug in and power my 12v imaginary friend.

 

of course, i dont run everything all at once really ever. i just did it a bunch when i first hooked it up to see if it could do it.

 

check out the pics of the engine bay mount i made for the second battery.

 

IMG_0749.jpg

 

IMG_0755.jpg

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I used a large solenoid from an RV parts place to tie the pos+ posts together, and the switch is tied to the ignition, so that the alt (XT6) charges them both while running, but they are isolated when the IGN is off...

 

I removed the jack holder, and pounded the area a little flatter, then bolted in a plastic battery tray to hold it.

 

PDC_0077.jpg

 

more pics

http://usmb.net/gallery/album238

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That is a great picture Mick.What type of adapter is that on top of your carb?(Also the one that goes back to the spare tire area with the filter?)

 

it's the very bottom one on this page...

 

http://www.jameng.com/products/index.phtml?section=14

 

it allows me to run a small round 6" chrome round air filter holder.

http://www.ultimatesubaru.org/80s/mick/gallery/holley5.jpg (back when I had the Holley on)

 

the bent section that goes back is a modified supercharger pipe off a thunderbird.

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Yep I did basically the same thing as Mick, big huge solenoid to tie them together when ign is on, seperate when off. I run my starter, and all *extra* accessories off my 2nd battery. Main Battery powers everything else for the car. Works great with my 100amp GM Alt, this is all in good prep for running a winch someday.

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just use one ...try an optima yellow top deep cycle battery ...I mean your not cranking over a diesel ....

 

with two batteries that's a serious weight penalty...too! If ya want some real batteries try three group 31 batteries!!! It'll crank over any frieghtliner around!LOL!:grin:

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So will the optima handle running offroad lights and a nice sound system for a fairly long peroid of time at low speeds or idle? How do they handle running a sound system with the car off for a while? Anyways, what im getting to is...dual battery setup or single optima?

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So will the optima handle running offroad lights and a nice sound system for a fairly long peroid of time at low speeds or idle? How do they handle running a sound system with the car off for a while? Anyways, what im getting to is...dual battery setup or single optima?

 

I have yet to really see what my Optima will do, but I'm gonna be lookin real spiffy, cause I got one in now and a second sitting here for the dual batteries. Dual optima's??:eek: :eek:

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  • 2 months later...

I had a Yellow Top Optima in my truck w/ an 1800w stereo. Accidentally left the keys in the "on" position and the stereo going. Lasted about one hour. My friend did the same in his truck only in "accesories" w/ the volume down and maybe an 800w stereo, lasted 6 hours before he realized and started the truck. Mine, I had to get jumped and it KILLED my Yellow Top. Now I have a Blue top, but I haven't tried that "test" again as it is expensive to replace Optimas (w/o your receipt that is). I'd like to run dual batteries as well once I get my Wagon going and get all my lights and then a winch when I have the $$$.

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I have a 270CCA battery... Yeah, I know, TINY! But it starts my EA81 with NO WORRIES what so ever. I've even flattened it 5 times to the point where it only just lights up the dash lights. It came in the car when I got it about 21months ago and it looked pretty used then. It's not a really known brand or anything, and it's the smaller version (not the standard size that fits in a Subaru.) I keep saying to myself I'm going to have to replace it, but it's just a brilliant battery.

 

A second battery wouldn't help with cranking if setup normally. The point is the isolate it from the other battery. So the primary battery runs the car and starts it. The other runs all your lights, and accessories.

 

I went out with a Subaru club to do some offroading and there was a guy who had a EA82t in his Brat. He setup the aircon unit as a tire inflator and also with a surge tank he made up he could use a rattle gun to undo and do up wheel nuts. It wasn't perfect, but it worked.

 

How big of compressors are you using Brain? How many Amps do they draw?

A good battery holds about 60Ah. It should still be able to start a Subie with 20Ah in it. So thats 40Ah you can use while the car is off. 100watt light (8.3A) can run for over 4 hours before you can't start your car. Unless you want to run campsite things from your second battery I reckon just spend the money on an expencive replacement one. My brother put a 600CCA Exide battery in his subie because he planned on putting a winch in it. And the guy at the shop said that one should do fine for even a big 4x4 with a winch.

 

Just my few cents.

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