Anybody Use 2 Batteries?

[NatiDonkRyda 10+ year member]

I currently use 1 Optima Red Top in my 71 impala to power everything. But, I want to mount a separate battery in the trunk to power my amp, subs and HU. I know I just pull the 4 gauge wire and simply connect it to the new battery in the trunk, but what do I power the HU with the new battery since it runs to the fuse box?

Need advice from someone who is doing this...

Click to read more...

 

[tez4life Premium Member]

First of all, if your going through the trouble of running a second battery in the trunk, I would upgrade to 0/1 gauge first. I kind of dont understand your question, if your HU is being powered by your fuse box, that will remain the same with the new battery. Why not just leave the HU on the fuse box, it does not pull hardly any current anyway?

 

[jco1385 5,000+ posts]

you should just leave the HU how it is. you're just attaching your + cable to the + on the second battery. you can either pull a - cable from the front - post or you can just ground it to the chassis in the back. then from there you would run your leads for your amps from the rear battery. be sure to install proper fuses between the batteries. some say one is fine, others say one within 18" of each battery. and obviously between the battery and the amps

 

[NatiDonkRyda 10+ year member]

First of all, if your going through the trouble of running a second battery in the trunk, I would upgrade to 0/1 gauge first. I kind of dont understand your question, if your HU is being powered by your fuse box, that will remain the same with the new battery. Why not just leave the HU on the fuse box, it does not pull hardly any current anyway?

I see what your sayin, but I want to be able to power my music with the car all the way off, no key in ignition. I dont have that Accessory option on my car (on older cars you can turn the key 1 notch towards you for accessory to use radio, dont have that for some reason), I have to turn it to the Start position and they will pull too much current.

 

[jco1385 5,000+ posts]

if you're gonna be running this w/ the key off as in car not running you'll also need an isolator so you can start your car back up

and you can just run a new wire to the HU (w/ a fuse) and put a switch on it if you wanted.

 

[tez4life Premium Member]

I see what your sayin, but I want to be able to power my music with the car all the way off, no key in ignition. I dont have that Accessory option on my car (on older cars you can turn the key 1 notch towards you for accessory to use radio, dont have that for some reason), I have to turn it to the Start position and they will pull too much current.

I see now, that makes since. You could just run your HU's 12v Power, Ignition, and Ground wires to the rear battery and put a isolator on the power wire going to the second battery. That way, you could play till your hearts content, and not worry about killing your red top up front.

 

[NatiDonkRyda 10+ year member]

you should just leave the HU how it is. you're just attaching your + cable to the + on the second battery. you can either pull a - cable from the front - post or you can just ground it to the chassis in the back. then from there you would run your leads for your amps from the rear battery. be sure to install proper fuses between the batteries. some say one is fine, others say one within 18" of each battery. and obviously between the battery and the amps

But how can I get my radio to work even with the car off and no keys?

 

[tez4life Premium Member]

if you're gonna be running this w/ the key off as in car not running you'll also need an isolator so you can start your car back up

Beat me to it, aint you suppose to be working, lol?

 

[jco1385 5,000+ posts]

Beat me to it, aint you suppose to be working, lol?

its friday and boss man is not here...//content.invisioncic.com/y282845/emoticons/veryhappy.gif.fec4fed33b4a1279cf10bdd45a039dae.gif

 

[tez4life Premium Member]

its friday and boss man is not here...//content.invisioncic.com/y282845/emoticons/veryhappy.gif.fec4fed33b4a1279cf10bdd45a039dae.gif

Touche' lol.

 

[NatiDonkRyda 10+ year member]

I see now, that makes since. You could just run your HU's 12v Power, Ignition, and Ground wires to the rear battery and put a isolator on the power wire going to the second battery. That way, you could play till your hearts content, and not worry about killing your red top up front.

Ok whats a isolator? Post a pic if you can...

 

[tez4life Premium Member]

Ok whats a isolator? Post a pic if you can...

http://cgi.ebay.com/ebaymotors/PAC-200-PAC200-Amp-High-Current-Battery-Isolator-Relay_W0QQcmdZViewItemQQcategoryZ33574QQihZ007QQitemZ170201767694QQrdZ1QQsspagenameZWDVW

I just picked that as a example, its just a type of relay that goes on the power wire feeding the second battery. It keeps the second battery from pulling current from the first battery if it begins to discharge. That keeps you from getting stuck somewhere.

 

[UndercoverPunk 5,000+ posts]

It's a big *** relay. If you want to turn your HU on with the car off you can always just rig a switch to feed it 12V whenever you want, it's pretty simple, and will give you the result you are looking for.

The Isolator would be a good idea so that you only drain your rear battery, and therefore when you're done, you will always have enough juice to crank the motor. I don't have one, but I don't sit around listening to my music with the car off. I've killed my batteries once while I was working on the car, and it too me 4 or 5 days of having the hood up constantly and my stereo at a decent volume. (Though, my stereo is also quite small at the moment.)

 

[NatiDonkRyda 10+ year member]

It's a big *** relay. If you want to turn your HU on with the car off you can always just rig a switch to feed it 12V whenever you want, it's pretty simple, and will give you the result you are looking for.
The Isolator would be a good idea so that you only drain your rear battery, and therefore when you're done, you will always have enough juice to crank the motor. I don't have one, but I don't sit around listening to my music with the car off. I've killed my batteries once while I was working on the car, and it too me 4 or 5 days of having the hood up constantly and my stereo at a decent volume. (Though, my stereo is also quite small at the moment.)

Ok so where in the car does the isolator get installed?

 

[jco1385 5,000+ posts]

probably the trunk. wherever you can fit it really