SuthernFlames316

yea i got a 99 gmc sierra xcab. i have a redtop optima battery. im runnin two power wires off of it powering a punch 500 and a punch 160. i have a stinger 1 farad capacitor. i want to put 2 optima batteries in the bed to power my amps and just leave the other under the hood for the truck itself. would i need to hook the 2 batteries up to an alternator, or would they be fine alone just hooked up to the amps. would they last long? i need advice what to do.

Snootch

iTrader: (3)

If youre running extra batteries, thay need to be run off the truck's electrical system. connect the batteries in back with the battery under the hood with some 2 or 1/0 gauge wire. Fuse that wire, just like you would if you were running it to amps. Next, purchase a large solenoid that will disconnect the rear batteries when the truck is on, and connect them when the truck is off. You will be better off with a 100+amp solenoid than an isolator. There are too many negatives to using isolators. This way, the batteries are isolated from the starter battery. However, you will probably need to upgrade your alternator should you choose to run two extra batteries. Charging three batteries will be a load that the stock GM alternator won't like. I think that you might be able to use the stock alt. if you only use one extra battery though. Now before anyone starts the name calling, and thinks that they know better, let me say that this is my OPINION, and it's what ive learned over several years of doing car audio. There may be a better way of doing this, however, this is the way i've seen batteries added to a stock electrical system. -My $.02, and good luck

SuthernFlames316

so you would connect the two batteries in the back? like connect the positives together? and then run and fuse power cable to the positive on the battery under the hood?

Snootch

iTrader: (3)

Correct. Wire all the positive posts batteries in paralell. Connect all the grounds to a good solid ground to the frame nearby. Check out this link. this should explain things a little better for you:
http://www.bcae1.com/battiso.htm

raceguy333

does that not seem like overkill? i'm running about twice the power (1 1000watt rms, 1 ~300watt rms) off a single optima and single 1F cap with zero problems..

Snootch

iTrader: (3)

I'm running 1500wrms with stock alt. and a yellowtop in my system, and don't have a problem either. The reason to have external batteries for the audio system is to provide extended listening time with the engine off. You could bump the system for hours at max volume, And still start the car.