Straight dope

[2023 LTZ]

Enthusiasts
Is there reason to believe that different batteries can be safely separated by a battery isolator?
Looking to add a deep cycle to the mix.
Battery companies recommend when adding a second battery that they be the same. The isolator companies insist there’s no benefit in having a second battery if it’s not used while the ignition is off.
Camping enthusiasts begin speaking of air conditioning, lighting, pumps, hours of use between charging.
I’ve gathered that I can add a deep cycle to my trunk and have it isolated from the front and feeding my amps. I believe the alternator is capable of charging it and the start battery as well as the electrical demands of the vehicle while it’s driving.
I have a stiffening cap but this seems less than what’s needed. I believe the alternator will never put out a steady voltage so I’m over that but wonder if this second battery will “cushion” the electrical dips that the system sometimes experiences.
Is it right to think using this deep cycle will cushion the higher demands of my audio system?

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[metalheadjoe 10+ year member]

The only reason for an isolator is to guarantee you can start the engine at the end of the day. Beyond that, you won't have any problems parallel'ing two like or unlike 12v batteries unless one of them is tired.

 

[hispls 5,000+ posts]

I have a stiffening cap but this seems less than what’s needed.

Get your music going at a reasonable listening level and disconnect the +12 at the battery and see how long that capacitor keeps your amp powered up and playing.

Joe is correct.

 

[2023 LTZ]

Well it’s lightning and snowing here.
I found a thread which a person asked all the questions I wanted to know.
I rewired the power. 4/0 ground in rear to replace the 1/0. Configured the power wires to have a more appealing look as well as incorporating that deep cycle in w the cap.
I drove around town pounding some drake, great bass, and did see 12.7. That’s at least 1v better.
Still have that extra delco battery in the trunk for emergency.

 

[2023 LTZ]

Aaaaaallllrighty then..
Working the bugs out of this sucker has been a long time coming.
So that deep cycle offers a slight improvement, I believe that 4/0 ground was a step in the right direction, to top that off I re used the 4/0 alt to start battery. I had taken it off as a part of my theory of why it was over charging. Now it seems to be the perfect combination to deliver the power needed and the voltage whilst driving stays above 12 w sub at close to full and at full volume. Yeah I may be able to eek out an increase on the gain but meh..
Pretty pleased.
Looking forward to bucket washing and buffing this big biotch.

 

[audiobaun 5,000+ posts]

Aaaaaallllrighty then..
Working the bugs out of this sucker has been a long time coming.
So that deep cycle offers a slight improvement, I believe that 4/0 ground was a step in the right direction, to top that off I re used the 4/0 alt to start battery. I had taken it off as a part of my theory of why it was over charging. Now it seems to be the perfect combination to deliver the power needed and the voltage whilst driving stays above 12 w sub at close to full and at full volume. Yeah I may be able to eek out an increase on the gain but meh..
Pretty pleased.
Looking forward to bucket washing and buffing this big biotch.

I recommend Mothers Polish. pretty good stuff or just about anything with Carnuba

 

[2023 LTZ]

I’ve been using meguires ceramic and a buffer. Probably clay bar first. Once per yr fir the bar seems adequate. It’s a size bigger from the times Ive waxed it.
Ready for melting snow!

 

[2023 LTZ]

I realize this is older yet I want to inform y’all I had a bad connection. A lead from the voltage sensor was crimped into the ground as it was originally yet somehow things changed for the better when I remade that ground and attached the lead separately.
4/0 from alternator to battery and from battery to chassis and battery to engine. 2nd interstate deep cycle in the trunk on 0ga. That is after the 2k farad cap.
0ga from front to back.
No more high voltage only high volume and bass that occasionally that rattles my ear drums and impedes my breathing.