CCA for second battery

[kingjd7 10+ year member]

Sooo.. I have a American Bass PH-2500MD with a single RE SE 10" in my 2003 Saturn Vue, I have one run of KnuKonceptz 0 gauge ran to the back about 20' in length. I'm getting voltage drop from 13.8 to 11.7. I was thinking I need a AGM battery in the front and one in the back, i'm trying to stay away from a HO alternator. Can I put a second battery in the back with the 0 gauge CCA? Will this help not need a HO alternator? To be honest I would like to only have one battery in the front if possible. Any help is appreciated.

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[dvcevoblack 10+ year member]

Have you done big 3?

 

[Beans]

Why so long on your run? Is there an excess just spooled up somewhere or did you misjudge the length?

 

[kingjd7 10+ year member]

I have done the big 3 with 0 gauge OFC...well kind of. I still need to do the alt to battery. I actually forgot all about it. And I have a couple feet wound up in case I want to move the amp to a different location.

 

[The Camry]

I have done the big 3 with 0 gauge OFC...well kind of. I still need to do the alt to battery. I actually forgot all about it. And I have a couple feet wound up in case I want to move the amp to a different location.

Alt to battery is the most.important one. That's like having huge grounds and a small power wire. The alt to battery is what allows high flow of energy

 

[rfluvinmf 10+ year member]

If you already have 20ft of OFC run to the rear of the car, you should be fine. Add an AGM up front and one in the rear, connect them using the 20 ft run currently in the vehicle. Connecting the amp to rear battery with a short run of CCA would be just fine. Complete your BIG3.

 

[fly_marlin]

I think you also need an isolator.

 

[adulbrich 5,000+ posts]

I think you also need an isolator.

NO. You will not need an isolator unless you play your system with the car off a lot.

 

[supra1987]

I was thinking I need a AGM battery in the front and one in the back

find the biggest one you can fit up front and go from there.might not need two,they tend to be heavy,imo agm's are far superior to any stock battery.also as stated above,alt to battery run is important.

 

[fly_marlin]

NO. You will not need an isolator unless you play your system with the car off a lot.

I'm sorry, I don't believe that to be true. If the alternator is unable to supply sufficient current, which is the case now and that's why he needs another battery, then the 2nd battery will be supplying the power. If the 2nd battery runs out of juice, it'll start ******* it out of the starter battery. One of the reasons to get a 2nd battery is to ensure that you can start your car even if your 2nd battery is drained. An isolator ensures just that.

 

[LosIsATool 5,000+ posts]

I'm sorry, I don't believe that to be true. If the alternator is unable to supply sufficient current, which is the case now and that's why he needs another battery, then the 2nd battery will be supplying the power. If the 2nd battery runs out of juice, it'll start ******* it out of the starter battery. One of the reasons to get a 2nd battery is to ensure that you can start your car even if your 2nd battery is drained. An isolator ensures just that.

Power is pulled from the highest voltage supply. The 2nd battery won't drain any lower than the front. If the batteries are getting drained that much a alternator is the only fix

 

[fly_marlin]

Yea. We already know alternator isn't supplying enough current. 2nd battery is just a patch and since it doesn't generate power, its voltage may also drop. So to ensure the car starts, probably best to go with an isolator. Though HO alt is the ultimate solution.

 

[wew lad 5,000+ posts]

You need an isolator if you run two dissimilar batteries together, or batteries with different resting voltages, or different cca ratings. Stop telling people you don't need it unless you run it with your car off, a battery isolator does more than turn off your starting battery when the key is off. It prevents current flow between the batteries.

OP, a battery will help but don't expect it to be a solution. You will likely still drop to your battery resting voltage because you're unable to pull more current from your alternator than it's able to produce. Keep in mind as soon as you use any battery capacity your alternator now has to charge the battery and run your amps.

 

[fly_marlin]

So all in all, save the money on the battery for now and invest in an HO alt. I think you should be happier in the long run.

 

[adulbrich 5,000+ posts]

I'm sorry, I don't believe that to be true. If the alternator is unable to supply sufficient current, which is the case now and that's why he needs another battery, then the 2nd battery will be supplying the power. If the 2nd battery runs out of juice, it'll start ******* it out of the starter battery. One of the reasons to get a 2nd battery is to ensure that you can start your car even if your 2nd battery is drained. An isolator ensures just that.

It is true. He does not need a battery isolator.

You need an isolator if you run two dissimilar batteries together, or batteries with different resting voltages, or different cca ratings. Stop telling people you don't need it unless you run it with your car off, a battery isolator does more than turn off your starting battery when the key is off. It prevents current flow between the batteries.
OP, a battery will help but don't expect it to be a solution. You will likely still drop to your battery resting voltage because you're unable to pull more current from your alternator than it's able to produce. Keep in mind as soon as you use any battery capacity your alternator now has to charge the battery and run your amps.

Stop telling people they need a battery isolator. Cold cranking amps have nothing to do with this whatsoever...

People run different batteries all the time with no issue.