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Dual Batteries?


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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

 

 

not to hi-jack but do you know if this set-up would work on a hitachi carb..it just list on there site for a webber carb.. better question do you know if you could make it work?

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wow the battery for my saab(not offroaded and the driving lights don't stay on when off) has a 800 CCA battery(stock was supposed to be something like 275CCA.boy does it sure crank the starter over...Might need to look into a heavy duty optima for the subi...

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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.

 

true if you set it up with a normal isolator. If you just run an RV solenoid switch (on with IGN), then the second battery is avaialble for starting duty as well.

 

so if I forget to shut my lights off, or leave a dome light on by accident (like this weekend), it only drains the main battery.

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I put dual 750 CCA optima-knockoff (made by NAPA) blue tops in my Legacy, with way oversized cables. Most of the time, I plan to have the engine running when there's a big load, but I've got plenty of reserve capacity if the need arises. I had my alternator die a while back, and I drove around with the headlights and stereo on for the better part of two days and it didn't even crank any slower by the end of it.

 

Here's a pic...don't mind the shoes being dried out;) .

denali06%20033.jpg

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umm about the optima... my roo is still dead but (timing tensioner failed) .. i had to use crank the starter over 50 times with for at least 10 seconds... while i was figuring out the problem.. and also.. while i moped around in my roo i was listening to the stereo for around 20 mins (its rallyrusses old roo, Nice sound set-up) and then it still cranked it easily for me to get it in its spot in my driveway (My avitar Pic.... yes.. its still sitting there) OPTIMAS RULE :headbang:

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Heres my setup while it was in my 83 wagon

1525Picture_019.jpg

Red top for starting, group 31 blue for the deep cycle. The two boxes by where the snorkle tube exits are a ACR (automatic charging relay), it lets you pick a voltage for where it connects and disconnects the batterys. Has a override connect and disconnect switch inside. The other one is a three stage marine battery charger wired into the system. I used this when i was hanging out listening to music. Or if i wanted to top off the batteries for what ever reason. I have a gm 105 amp alt now too.

I used to work at big marine store and got all the goodies for cheap.

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that was by far the sexiest thing i have seen lately,besides the obvious ones(yeah,my ol'lady is hot)........

nice work mang,nice breather.

 

 

 

 

 

Heres my setup while it was in my 83 wagon

1525Picture_019.jpg

Red top for starting, group 31 blue for the deep cycle. The two boxes by where the snorkle tube exits are a ACR (automatic charging relay), it lets you pick a voltage for where it connects and disconnects the batterys. Has a override connect and disconnect switch inside. The other one is a three stage marine battery charger wired into the system. I used this when i was hanging out listening to music. Or if i wanted to top off the batteries for what ever reason. I have a gm 105 amp alt now too.

I used to work at big marine store and got all the goodies for cheap.

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The red top has 1100cca's and 55 AH, the blue top has 1000cca's and 75 AH. I had 4 55W lights and 2100w's of stereo. All the acc's are run off a seperate switch and fuse pannel. ( http://www.bluesea.com/ ) All these are marine rated, so most are over kill for a subaru but ohh well ( if your looking for high quality electrical componets in the seattle area go to Fisheries Supply ). That whole charging system is swapped into my legacy now to run the stereo. I'll probaly just run one group 31 blue in my off road car, i like how it looks in the spare tire holder.

 

heres a pic of the switch and fuse pannel in my custom dash i made.

1525Picture_004.jpg

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So i was lookin through my JCwhitney catalog... and looky what i found here:

 

http://www.jcwhitney.com/autoparts/Search?catalogId=10101&storeId=10101&sku=gm141846&searchbtn.x=17&searchbtn.y=9

 

I may have to order me one of those :)

 

-Brian

 

Done and Done! plus a volt gauge and 3 sets of 55w spot lights, got them all wired and mounted yesterday, works great. im running them all off my second batt, which has the voltmeter so i know how much batt life i have when i have my lights on. i'll post pics as soon as i can.

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Done and Done! plus a volt gauge and 3 sets of 55w spot lights, got them all wired and mounted yesterday, works great. im running them all off my second batt, which has the voltmeter so i know how much batt life i have when i have my lights on. i'll post pics as soon as i can.

Wow you really jumped on this info didnt you! I cant wait to see the pics... these things are looking really really complicated!!!

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the jcwhitney system is really simple, it only took 2 hrs to install, which included going to pepboys and getting vac plugs for removing my carbon canister to see if the batt would fit there, it didnt, big waste of time! So i mounted it in the spare wheel well.

 

its a great system and simpler then wiring up a solenoid to the ign. just 4 wires when u think about it (alt to isolator, isolator to main batt, isolator to aux batt, and ground on aux batt.) bolt the isolator and aux batt down tight, and ur all set!

 

what took a while was wiring up the spots and batt gauge which i did the next day. that took 4hrs. drilling holes in bumper, roof rack, grounding roof rack, wiring lights to switches and aux batt, and wiring gauge to aux batt, and switchable 12v ingnition source for the gauges backlight. the gauge is contantly on, i figure it doesnt draw enough power to drain the batt so i might as well keep it wired all the time.

 

the system works fine with the stock alt, but the stock charge meter on the dash jumps when i have my turn signals on, so im gonna upgrade. prob to this http://www.partsamerica.com/ProductDetail.aspx?mfrcode=QLT&mfrpartnumber=P7157&parttype=11&ptset=A&sourcepage=SEARCHRESULTS

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Isolators are fine but you lose around 5% of your voltage which brings a fully charged 12.7v battery to around 12.1v. Solenoids are cheap and provide a lot of options, in connecting and disconnecting batteries. Qmans 165amp alt is huge, but you do lose about 5 hp per 50amps. I know qman has the power to turn that big guy but with my fairly stock 71hp I’d rather not take away another 10hp. My opinion is that if you have the battery capacity to run your needed accessories for the duration you want, then go ahead and run a smaller alt. The alt. can recharge while you’re not draining the system. That’s one reason I chose to use a hand crank boat trailer winch, over an electric one. It has double reduction gears and is rated with a 3500# working load. Run that off a snatch block and you are set. It’s a whole lot cheaper and lighter and doesnt pull huge amounts of amps.

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Heres how it looks in my legacy.

I made this little pannel the left switch switches the gauge between the two batterys. The right switch is the override for the relay. up is auto connect down is auto disconnect. The blue top is in the sub box in the rear. This allows me to run short runs of smaller wire from the battery to the amps instead of trying to run a large cable from the front. I just have to run a 6awg through a fuse and the relay from the front battery to the one in the rear.

lego_stereo.jpg lego_stereo_003.jpg lego_stereo_004.jpg lego_stereo_002.jpg lego_stereo_001.jpg

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Isolators are fine but you lose around 5% of your voltage which brings a fully charged 12.7v battery to around 12.1v. Solenoids are cheap and provide a lot of options, in connecting and disconnecting batteries. Qmans 165amp alt is huge, but you do lose about 5 hp per 50amps. I know qman has the power to turn that big guy but with my fairly stock 71hp I’d rather not take away another 10hp. My opinion is that if you have the battery capacity to run your needed accessories for the duration you want, then go ahead and run a smaller alt. The alt. can recharge while you’re not draining the system. That’s one reason I chose to use a hand crank boat trailer winch, over an electric one. It has double reduction gears and is rated with a 3500# working load. Run that off a snatch block and you are set. It’s a whole lot cheaper and lighter and doesnt pull huge amounts of amps.

 

you gotta realize that it's not going to be producting 165amps all the time... it will only produce that much when the load is drawing 165amps...

 

now drawing 165amps on a car is HUGE! that's equal to running almost 45 50W off-road lights... that's a lot of lights!

 

now even with a heavy heavy load (big big BIG stereo, lights, power converter, and the microwave in the backseat) you're still probably not going to be maxing the thing out... Ken runs a welder on his rig i think so his in the most extreme conditions might be drawing enough to kill 10hp... but then again he isn't going to be driving when he's welding...:-p

 

so running such an alt won't take 10hp outa your rig that you'll never see again... as a matter of fact it might even make it run better due to it producing more amps at a lower resistance in the alt making it more efficient... :)

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you gotta realize that it's not going to be producting 165amps all the time... it will only produce that much when the load is drawing 165amps...

 

now drawing 165amps on a car is HUGE! that's equal to running almost 45 50W off-road lights... that's a lot of lights!

 

now even with a heavy heavy load (big big BIG stereo, lights, power converter, and the microwave in the backseat) you're still probably not going to be maxing the thing out... Ken runs a welder on his rig i think so his in the most extreme conditions might be drawing enough to kill 10hp... but then again he isn't going to be driving when he's welding...:-p

 

so running such an alt won't take 10hp outa your rig that you'll never see again... as a matter of fact it might even make it run better due to it producing more amps at a lower resistance in the alt making it more efficient... :)

 

Excellent explanation. And all true!!

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heres the pics! first is the whole engine bay, second is just the batt and isolator, thirs id the batt gauge and 3 switches for the spot lights. the white switch nest to the gauge is the fog lights, the orange ones are the spots.

 

n10512430_30786749_8936.jpg

 

n10512430_30786750_9256.jpg

 

n10512430_30786748_8610.jpg

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