Help with Batteries For Daily

[Blackout67]

My setup is pretty much done appart from maybe getting some different door speakers and a battery.
I already have a single Group 34 AGM under the hood but it has trouble keeping up with my amps. I need a battery for 270 amps worth of power (combined fuse rating for amps). I rarely sit and play music and I'm usually driving around while jamming out but man I have a 15 inch subwoofer (tryna sell/trade btw) with a 4 inch coil and that baby takes some power to move it.

Firstly, how would I go about adding a second battery, secondly should I go for another AGM or a lithium cell and what would be the AH I need? I can never find a clear answer on this because everyone

 

[Bass Addict]

i have dynamatt on back doors,back wall,and floor

 

[Grimmjoww]

i have dynamatt on back doors,back wall,and floor

That thing is hammering!

 

[Bass Addict]

That thing is hammering!

yeah man,and the dust cap stays cool.adding that extra battery did the trick ! thats a 1750 watt rms 10

 

[Blackout67]

I have an unfused 2/0 wire running from the front battery to the rear battery with a disconnect. I then have a fuse block between the rear battery and my amp. I do not want anything in between my 2 batteries, I want them to function as one unit, I do have a disconnect I can access quickly if anything should ever happen.

Ok so no isolators or anything like that for you either? And you don't have any issues with them draining while not in use?

And for the grounds would I run it back to the battery ground and then ground that to the body or run separate ground from both my amps and the battery as well

 

[Bass Addict]

And for the grounds would I run it back to the battery ground and then ground that to the body or run separate ground from both my amps and the battery as well

depends.some people run ground from 2nd batt to amp.....me,i ground amps and batts to chassis which in my case,requires different grounding locations for shorter runs of cable.

 

[Grimmjoww]

Ok so no isolators or anything like that for you either? And you don't have any issues with them draining while not in use?

And for the grounds would I run it back to the battery ground and then ground that to the body or run separate ground from both my amps and the battery as well

Leave your battery in the engine bay the way it is but do the "Big 3". Then run a separate ground for the rear battery as close as you can to the chassis of the car or truck. No mine do not drain down, it's just like one huge normal battery.

 

[Bass Addict]

No mine do not drain down, it's just like one huge normal battery.

Exactly

 

[hispls]

I don't feel like going thru the trouble of deleting the under hood battery. I paid good money for it and when it fails I'll warranty it out no biggie.

Indeed. Again, if you don't mind the space and weight of a couple more AGMs there's no need to open that can of worms at the 3000W point.

How would I go about hooking up multiple agms?

I can't think of too many applications where an isolator is appropriate for car audio and "deep cycle" or not you probably don't want to deep cycle any sort of lead acid battery if you can help it.
Just connect the two + terminals with some heavy wire, ideally fuse within 18" of each + terminal so that if you have a failure in that cable neither battery will be able to dead short to ground. Fuse should be appropriate sized to your alternator.

Ground as close to the secondary batteries as possible, find a good spot with some thick steel, grind/sand off paint until it's shiny and goop some vaseline or dielectric grease over it after it is secured to prevent corrosion.

 

[Blackout67]

Indeed. Again, if you don't mind the space and weight of a couple more AGMs there's no need to open that can of worms at the 3000W point.


I can't think of too many applications where an isolator is appropriate for car audio and "deep cycle" or not you probably don't want to deep cycle any sort of lead acid battery if you can help it.
Just connect the two + terminals with some heavy wire, ideally fuse within 18" of each + terminal so that if you have a failure in that cable neither battery will be able to dead short to ground. Fuse should be appropriate sized to your alternator.

Ground as close to the secondary batteries as possible, find a good spot with some thick steel, grind/sand off paint until it's shiny and goop some vaseline or dielectric grease over it after it is secured to prevent corrosion.

What would be a good battery? Preferably a big enough one so that I don't have to buy two

 

[Grimmjoww]

It's this simple really, you can go with XS or Odyssey but you don't have too. https://www.walmart.com/ip/EverStar...up-Size-H8-12V-900-CCA/380996471?athbdg=L1103

 

[Blackout67]

It's this simple really, you can go with XS or Odyssey but you don't have too. https://www.walmart.com/ip/EverStar...up-Size-H8-12V-900-CCA/380996471?athbdg=L1103

So it doesn't have to be the same group size? My current AGM is a group 34 and it's about 7-8 months since I bought it

 

[Grimmjoww]

So it doesn't have to be the same group size? My current AGM is a group 34 and it's about 7-8 months since I bought it

No, group size indicates the actual amperage and size of the battery. All 12V batteries will play nice together (except some lithium batteries) so you don't have to worry about that.

 

[metalheadjoe]

Ok so no isolators or anything like that for you either? And you don't have any issues with them draining while not in use?

And for the grounds would I run it back to the battery ground and then ground that to the body or run separate ground from both my amps and the battery as well

Batteries don't drain each other unless one is bad.

 

[Blackout67]

Batteries don't drain each other unless one is bad.

Ok. Would it be ok to pick up a used one? I've heard that using different aged batteries is a bad idea

 

[Grimmjoww]

Ok. Would it be ok to pick up a used one? I've heard that using different aged batteries is a bad idea

Go new. Not that much more expensive and you know what your buying with a warranty. Used batteries have no warranty and there is no telling how it was treated. Just my .02