Dual Battery Questions

[tooshort_128 10+ year member]

I just got a new truck and am ready to start brainstorming new install in my Tahoe. It already has a battery tray up front so I already have a spot for my second battery. I still have the factory battery in the stock location but have a Stinger SP1000 I want to use. I'll be running about 1200-1500wrms and will be using all 0 gauge cables. I need to know the best way to wire all this up and if I should use an isolator or not since I have two different batteries. I've read to go + to + and - to - on both batteries, but that I should also have a run of + to the amp and also a run of - to the amp. I was thinking it would suffice to have one run of + from the first battery to the second battery and then to the amp, but ground each battery and the amp individually. I know where I'm adding fuses but want to know if this will work.

Sorry for the long question...

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[orphe 10+ year member]

use an isolator if you plan on playing your music with the engine not running a lot.

 

[brandon_s0854 10+ year member]

I would ground the batteries together personally. Grounding the amp separate shouldn't matter as long as you make sure it is in fact a good ground. An isolater isn't necessary, but as orphe said, you'll want one if you plan on listening with the vehicle off for long periods.

 

[ngsm13 5,000+ posts]

Also, if you have dissimilar batteries, an isolator is a good idea.

Either way, you'll still need to ground both batteries to the same location. Also, fuse your run of 1/0 from the secondary battery to your amplifiers just like normal.

 

[tooshort_128 10+ year member]

I wont be listening with the car off but I will have dissimilar batteries so I guess I will have to use an isolator. So it looks like I'll connect positives and negatives of both batteries and ground them to the same spot up front, then ground the amp out back.

 

[tooshort_128 10+ year member]

Can anyone recommend a decent battery isolator that won't break the bank?

 

[disturbed471985 5,000+ posts]

As long as both are of same tech and resting voltage your good to go. Agm with Agm, etc. I have always used different brands batts and not one issue doing so..

 

[ngsm13 5,000+ posts]

As long as both are of same tech and resting voltage your good to go. Agm with Agm, etc. I have always used different brands batts and not one issue doing so..

Indeed. I just would not parallel a regular battery and a deep cycle without an isolator. Even with the same batteries, there will be somewhat of an equalization phase between the two, nothing that will harm them much though.

 

[tooshort_128 10+ year member]

I'll be using a factory GM battery and a Stinger SP1000 so the isolator should be used right?

 

[ngsm13 5,000+ posts]

I would use an isolator.

 

[tooshort_128 10+ year member]

can you recommend any that do the job and are relatively cheap?

 

[ngsm13 5,000+ posts]

What size amp? Size accordingly...

Battery Isolators | Battery Relay | Isolators & Relays

 

[tooshort_128 10+ year member]

I'm only going to be pulling a max of 120amps so the 200 amp isolator should be more than enough. All the fuses I have are from a previous install and are 300 amp fuses, that's ok right?

 

[disturbed471985 5,000+ posts]

the 200amp relay will do. Yes leave the wire fused at 300amps as I assume its 0awg and is fused based on the wire as it should be.

 

[tooshort_128 10+ year member]

One last question.....since both batteries are going to be under the hood, the runs are only going to be 7-8 feet. Is 0 gauge really necessary or will 4 gauge do?