Big 3 done still getting voltage drops

[93ls1rx7]

Hey guys newbie here, this is my first post.

Here are the details:

I have a 1993 Mazda RX7 with a 408 CI LS1 (512rwhp through an auto) and I have a system in it.

Battery/Wiring:

Optima Red Top battery located in the rear storage bin located behind the passenger seat.

Main power wiring is 0 guage and runs to the starter then to the alternator.

Main ground is 0 guage and runs about 12" to the body. I also ran a second 0 guage from the battery directly to the engine block.

From the engine block I have 2 0 guage grounds going to the chassis on clean bare surfaces.

Power to the amps is fed directly from the battery to the amps and the amps are located about 3 feet of wire from the battery.

Alternator: 200 amp alternator

Electronics:

Nothing to major.

Head unit: Pioneer Avic D-3

Front door speakers: JL Audio 5.25 components with crossover

Rear Speakers: 6 1/2 3 ways JL for fill

Subs: 3 JL Audio 8W3's

Amps: Kenwood KAC-X4R for the front and rears

Kenwood KAC-X1R D Mono for the subs

Symptoms:

4 channel amp voltage (displayed on the amp) sits at ~ 14.7 volts all the time. Occasionally it will drop to 14.5 volts or even 14.3 but I am not worried about that. When the other amp draws a ton of current this one drops a little as well but it isnt the cause.

The amp for the sub sits at ~14.7 volts with the radio off (again basing all this off the amp display). When I turn the radio up I start losing voltage to the sub amp. When I am running the system at about 90% when I get a sharp hard bass note, my voltage drops to around 11.8 and recovers fairly quickly back to the 14 range. If I am listening to a song with a string of fairly fast hard bass notes, I have seen the voltage degrade down as low at 10.7 volts. At this point it isnt only effecting the system but also the car as the PCM idles the car up itself.

So here is the question:

What is the answer at this point? I dont want to add another full size battery.

Is a yellow top the answer? Is a Batcap 400 the answer? Is this just something I have to deal with?

Things out of the question:

I will NOT add a second alternator or anything like that.

Things I would prefer not to do:

I would rather not add a second fullsize battery.

The cost to get something isnt a concern.

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[dave_damage 10+ year member]

Nice detailed post. This is real strange to hear tho. How old is the red top?

 

[93ls1rx7]

The red top is less than a year old (maybe 8 months). Charges fine and never been drained.

 

[Enellz 10+ year member]

Hmmm get the alternator tested, and maybe upgrade the front battery. Trail and error dawg

 

[lacboi 10+ year member]

nice motor swap

 

[lovindabass]

look into missing link audio modules. that may help with a little higher voltage and will allow you when it drops to still be higher than what it is. also maybe a big cap would fix the storage problem. you seem to not need a lot of power and a big cap say 20 or 30 farads should help. I had the same issue before I got 2 30 farad caps and the problem went away. *i also added 2 batts with it. had a lil drop with bats then added the caps and bam fixed!* still have the caps if you want em lemme know