Battery Wiring

[JoshM20 0]

Hey Guys,

I am going to have a yellow top under the hood and a spare bat in the trunk. What I was wondering is how do you wire these? Do you run them in series and then the amp from the rear batt?

Josh

[JimJ 11]

Parallel...

[ANeonRider 3]

Series = Sum the voltages

Parallel = Sum the currents

[ABXX49 20]

Are you always supposed to use an isolator from the front battery to the rear battery as well?

[JoshM20 0]

ok so I should run in parallel so the voltage won't drop right?

[ANeonRider 3]

Parallel so that your voltage isn't 24V...

[lee 2]

Parallel so that your voltage isn't 24V...

Exactly! The car wouldnt like it that much

[JoshM20 0]

so what's the point of running another battery?

[ANeonRider 3]

More current carrying capacity... like I already said:

Series = Sum the voltages

Parallel = Sum the currents

[95Honda 486]

Battery isolators are NOT what you want for the high current demands of car audio, no matter what the "expert" at the RV/auto parts store tells you...

Additionally, you will never, and I mean never(!) hook up a 12V car battery in series with another for anything but a 24V vehicle. Period.

By wiring in parellel, as everyone has advised, you are increasing the current delivery of the 12V electrical system in your vehicle. Your are also lowering the total ESR of your electrical system and increasing your instantaneous current delivery every time you add another battery in PARELLEL and decrease the DC resistance of you wiring. This is all a good thing.

Just remember one thing, something has to recharge all those batteries, it is a balancing act, if you consume more current you must supply more current, and the only thing that supplies this current is your alternator....

[jonbearsmt 919]

Are you always supposed to use an isolator from the front battery to the rear battery as well?

not true at all...

[JoshM20 0]

Just remember one thing, something has to recharge all those batteries, it is a balancing act, if you consume more current you must supply more current, and the only thing that supplies this current is your alternator....

So should I get a batcap? or a capcitor? Or see how it runs for now with the two batts and save up for a H/O Alt.

[KU40 173]

only if it's one of the big batcaps that's basically a battery. not a capacitor, that is useless. Not to mention that for the same price you could get an actual battery that would do 1,000,000 times more good.

[JoshM20 0]

A batcap is easier on your stock alt right? Or am I confused about that.

[ANeonRider 3]

A batcap is easier on your stock alt right? Or am I confused about that.

Confused.

[JoshM20 0]

so what is the point of a batcap? I know what they do, but why would you get one of those over a battery? Because they discharge faster? Or do they?

[JoshM20 0]

Ok New Question guys, I have never hooked up a system with two batts, Do I need to a wire from both leads up front or can I use the Ground to act as a negative lead?

[blue fury 3]

Its always + to +, but as for the negatives, you hook them up to whatever has the least resistance. Its usually - terminal to - terminal > frame > sheet panels. Many people ground the back battery to the frame, many competitors use multiple runs from front to back. Don't skimp on the wire guage whatever you choose.

[JoshM20 0]

Its always + to +, but as for the negatives, you hook them up to whatever has the least resistance. Its usually - terminal to - terminal > frame > sheet panels. Many people ground the back battery to the frame, many competitors use multiple runs from front to back. Don't skimp on the wire guage whatever you choose.

I'm using 1/0 gauge, I just don't feel like taking out the seats to run it down the middle. I plan on deading it later on, so maybe I will just groud it to the frame and when I do that I will add the other run of gauge.

Thx

Josh

[95Honda 486]

If you have a full frame car and not unibody, running ground wires to the back is pointless... It would take tons of runs of 0 gauge to have lower resistance than a frame if you do your connections properly.

If you have a unibody car then you may benefit from running a ground(s) to the back.

[JoshM20 0]

If you have a full frame car and not unibody, running ground wires to the back is pointless... It would take tons of runs of 0 gauge to have lower resistance than a frame if you do your connections properly.

If you have a unibody car then you may benefit from running a ground(s) to the back.

How would I find out if I have a Unibody car? Can I look at it and tell or do I need to dig up some info on it?

[joselmartinez 0]

I'll say that you sould upgrade your alternator and run "0"g from the front Battery to the back Battery (both+/-)

[95Honda 486]

If you have a full frame car and not unibody, running ground wires to the back is pointless...

Just to reiterate.

Also, if you can see definite frame rails under the car that go all the way from front to back, it isn't unibody. But, alot of cars these days are unibody. I bet a web search would tell you within a few minutes if you have a unibody car or not.