Electrical problem? Help!

A yellow top is more tailered for car audio. Rep tops if I remember correctly are for low amp draws over a period of time.. Dont quote me on that.

get the red top checked u could have cracked one of the lead plates, cores what ever they are. even though it is a sealed agm battery it still is a lead acid battery, just with the acid absorbed in the glass mat. they can still have bad cells

Optima Yellow Top Battery - Deep Cycle YellowTop Batteries

Optima Red Top Battery - RedTop Batteries by Optima

Optimas are overrated they cost more for nothing. I'd take an autocracy AGM over the optima any day due tout having more plates and therefor more capacity. The trick is finding a good AGM battery

i had a good 7 years on my redtop before i replaced it. it was still fine, i just wanted a new battery. always had systems running on it. red tops are made as a starting battery - which is what the main battery should be. i've heard more issues with yellow tops being used as a main battery and not being properly charged. not an issue with the battery as it is with the user - call it operator error - batteries need to be charged regardless of who makes them. optima's problem is that they are well known and used by plenty of people who don't know any better. a battery failure is 99% operator error and 1% manufacturer error.

sounds like you aren't charging your battery. your alt may be fine but too small to handle the load, so you drive around draining your battery and never actually fully charge it.

well i would say it should be enough. i would check all power connections to be sure they are all tight and good. i see you had the same issues with both batteries, and its coming and going for no reason. could be a loose connection under the hood. and if your constantly dropping into the low tens voltage wise, i would calm down on the volume as you could possibly blow the amp from under voltage.

and red tops are for starting, you would need a yellow top, but the red will"work". personally i would bring it back and get a yellow top, put the old battery back under the hood, and run the yellow top in the back.

if your alternator is causing you fits, the battery may make up for the amperage you don't have. also a 1200 watt amp should use about 90 amps of current. 40 % of your alternator is most likely being used by the cars systems and etc, so that's about 50 amps, leaving you 70 amps for your car audio. you can see @ peak amperage draw you don't have enough without a second battery, and i really wouldn't rely on the starting battery to make up the amperage you don't have.

so, either bring back the red top, and put the yellow in back, or put old battery under hood, and red top in back. if all of the above doesn't help, upgrade to a larger alternator. and check all wiring connections including alt to battery etc to see if they are loose.

If your 120a alternator has 83k on it, I can promise you it is not doing 120a any longer.

More/better batteries are only going to temporarily band aid the problem.

If you already have that many miles on the alt that amp might have done it in