batteries to alternator or battery??

[teen 10+ year member]

ok so i have 2 g31 dekas that will be in the back of my truck. should the run of power wire come from my optima red top up front, or directly off my alternator to the dekas?

any thoughts?

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[teen 10+ year member]

c'mon... nobody has different batteries in the back than they do up front?

 

[bhsdriller 10+ year member]

I've always done the runs of wire off the front battery..even when I had two different brands

 

[power-fanatic07 5,000+ posts]

I would do from the alt.

 

[Ineed$ 10+ year member]

I would do batt to batt

 

[helotaxi 5,000+ posts]

You should have already upgraded the wire from the alt to the front battery, so wiring to the front battery should equate to the same thing. Wire to the battery.

 

[teen 10+ year member]

It wouldn't be the same thing because wiring from front battery to rear batteries now means the batteries are wired together. I've read in some instances this can ruin the life span of some batteries.

And idk if it makes anymore of a difference considering im still unsure of what to do, but the optima is about 2 years old while the dekas are new.

 

[teen 10+ year member]

think im just gunna run it straight off the alternator.. an alternator basically just trickle charges so it would be like splitting up where that charge is headed, no? rather than charging the battery up front and then making its way to the batteries in the back, the charge would just make its way to them individually. idk makes sense in my head so i guess thats what ill do.. someone lmk if they think its a bad idea or its def the wrong way to go about this.

 

[ejschultz 10+ year member]

Wiring to the alternator or wiring to the battery is going to be about the same. Either way, the positives of the batteries will be connected to each other, one way or another. If you're worried about shortening the life of a battery because of having different age/brands, I'd recommend a battery isolator. That will let you safely run a rear battery bank off your alternator without having the front battery physically connected to the rear battery(ies).

 

[teen 10+ year member]

i suppose that was what i was looking for... so just because both battery positives are connected to the alternator, its still as if they're connected battery positive to battery positive?

 

[ejschultz 10+ year member]

Yes. That would be correct, assuming you did a big 3 upgrade. If you didn't, connecting to the alternator would still connect the positives of the batteries together, but you'll have a better connection for charging the rear bank. If you did the big 3 with sufficient gauge wire, then there won't be any difference.

 

[ejschultz 10+ year member]

Amazon.com: NOCO® 200 - amp HP Battery Isolator: Home Improvement

Something like that would be a good isolator to go with. It's going to be a little large so you'll probably have to get it into the back of your truck. It's going to require a couple of runs of wire to do that. You can get smaller relay type isolators, but the diode isolators (the one I showed you) are a better because they completely separate the front from rear battery and allow for completely separate charging.

 

[nateberrier 10+ year member]

It really doesnt matter. I would run them off the other battery though, sort of acts as a filter. I ran an interstate lead acid up front and a deka g31 in the trunk alllll summer and beat the crap out of them and let them sit and beat the crap out of them and then let them sit for weeks at a time. at the end of the summer both batts were still at 12.8

 

[audiolife 5,000+ posts]

How much total amplifier power? How much alt power?

 

[teen 10+ year member]

its a DD z2, so idk a few thousand watts. prolly not even enough battery power with just the two. but my subs cant take that much power either way so its not like the amps gunna be drawing a lot of power. and a mean green high output alternator. and obv big 3 done.