4 guage or 0 guage for dual battery

[ladorn45]

Hey everyone I am in the process of adding a second battery to my systema nd trying to figure out what guage wire to go with. I did the big three with 0 guage wire. Is 0 guage overkill for a dual battery setup and 4 guage will do or should i not cheap out and do the 0 guage wire. Any idea thanks everyone

 

[YukonXL04]

0ga for sure

 

[ccapehartusarmyINF.(ret)]

yes zero guage i recomend 1/0 guage welding wire
for what purpose are you adding a second battery stereo system?
the only reason to add a second battery is if you listening to your stereo for long periods of time with the engine off
if your stereo system draws more current then your alternator can put out you need a larger alternator not an extra battery
batterys cant create more current only a larger alternator can

 

[ladorn45]

I have a bunch of stuff hooked up to it and just wanted a second battery to be able to run things off it with out killing the main battery while the car is off. Also will probably add a ** alternator eventually.

 

[Sub]

I'd be less concerned about the 0 vs 4 gauge, and more concerned about adding a fuse or fusible link as close as possible to the second battery.

 

[ladorn45]

I am fusing both battery cables that lead to the master and extra battery. I was going to use a 250 amp fuse. Do you think that is enough or excessive

 

[Sub]

Excessive. Your factory wiring harnesses will have burned before the 250 amp fuse separates.

The largest fuse I've ever seen GM put in an SUV was a 125 Amp megafuse, for a circuit that powered an electric motor that had to be powerful enough to steer a fully loaded drive axle on a 3/4 ton 2500 for the Quadrasteer rear wheel steering system.

Have you measured the current draw of your accesories/stereo?

 

[ladorn45]

The fuse is for the zero guage wire going from the main battery to the senliod and from senliod to aux battery. It's not for any factory wiring. I have seen people put 80 amp fuses all the way up to 300. That's why I was confused on which to use. The amp wires and all accessories will be directly attached to the aux battery. So these fuses control the power that going from one bat to the other. And so far what I have hooked up to the aux battery is 120 amp fuse for radio an aux 30 amp and anther 20 amp for lights. So 170 amps from the aux battery so I wanted to leave room for upgrades hence the 250 amp. Not sure if this all makes sense

 

[Sub]

What is the continuous duty rating of your solenoid that separates and connects your two batteries?

If the continuous duty rating of that solenoid is only 100 amps, and you have a 250 amp fuse, then...

 

[ladorn45]

I went overkill and got the 500 amp soleniod rating just in case I upgrade my alternator or do anything demanding. I was going to do a 250 amp fuse but leaning to a 200 amp to be safe.