audio system going dumb

So recently installed a second battery to my system I have a Skar Audio SKV2 100.4 amp and a Sundown SFB1500.1D with a factory head unit and an Audiocontrol LC7I, ever since I added the second battery if a really loud bass note hits at causes the mids and highs to go half volume or so if that makes sense for the bass note hit, I'm thinking it may have to do with the way I wired the second battery. I am using the distribution block I have attached below which had 2 in and 4 out. The main battery is an AGM going into one of the ins and the second battery going to the other in on this block. to give you an idea how its wired, which the last link has a rough idea how it is wired. Except the kavsrover is the stinger distribution block and I am running all 0/1 awg wire expect to the skar which is 4 awg. All of my equipment is linked, thank you in advance.
LC7i | AudioControl
SFB-1500D – Sundown Audio
https://www.skaraudio.com/products/skv2-100-4ab-four-channel-car-amplifier

$40 Stinger SHD821 HPM Series MANL/MIDI Fused Power Distribution Block with Satin Chrome Finish

https://www.amazon.com/Stinger-SHD8...nger+distribution+block&qid=1619670000&sr=8-8
https://www.australiandirect.com.au/assets/alt_3/KADBWK8MM-VSROVER.jpg

 

You really should use identical batteries unless you are isolating them. It also doesn’t make sense to me that you would split the amplifier power feeds between the two batteries, by adding a second battery you are deepening the reservoir, not adding a second power source.

Odds are that by consuming power on one battery with bass, they are trying to equalize while you are also putting demand on the second battery and voltage is dropping considerably. Or, if you didn’t run a ground directly between the negative terminals you have an electrical potential difference between the two.

I don’t know how you have it wired up however, so it’s impossible to say what’s going on and how to remedy it.

 

Good stuff thanks. I’ve learned a good amount just reading you guys help other people solve issues.

 

Yeah if one battery is AGM and you haven’t done the voltage boost mod, you may not be fully charging your main battery in the first place.

 

What is the voltage mod you speak of?

 

Ok, so let me get this straight. understanding that you are not here to currently look at the setup and see what is actually wrong which I understand.
Both battery's are an AGM one Northstar Agm and the other just a genetic car audio agm because I'm not using an isolator is one problem, I know the ground is good I went to the frame and 80 grit the paint away and screwed it down. Also I do not know if this information helps I installed a voltmeter gauge and removed one of the cigarette plugs and plugged into that for voltmeter and before when the bass would hit the voltage would go from 13.2 down to 12.5 which I haven't had that issue since i added the second battery but i do not have voltmeter

 

I think most AGM’s are supposed to service charge at like 14+ volts. And even the float charge is still pretty high on them.

 

https://www.tacomaworld.com/threads/the-northstar-agm-battery-voltage-booster-upgrade.604478/

 

First off my bad I gave you the wrong battery it’s an odyssey extreme group 34 r battery and that link you have is only researched for a 24, 27, 31 so I don’t know if that would still work for me. Also it sounds like I need to upgrade my alternator from what you are stating from a 90 amp to a high output alternator which what you are stating. Since I’m the tacoma there’s a voltage regulator control by the pcm so that the alternator only puts out what the truck needs for stock application