I'm not sure what the problem is with your system ?
But I'm running almost the exact same system.... 3Kwts + a few more... a 100 ah AGM battery, an XS Power 500 farad supercapacitor, and if the truck and alternator are cool, I might drop from 14.5 volts to 14.3 volts, playing hardcore bass tracks at full tilt !
If I'm driving, with rpm's up to 1500 or higher, my voltage will stay pegged at 14.5, even when beating the heck out of the system ! (Which I think is pretty bad ass
)
Now granted, on a hot day, after everything is fully charged > with the stereo turned completely off, my truck will charge at 13.8, then if I turn the system on and start beating it, again will drop about .2 volts to 13.6..... but if I'm driving and have my RPM's up 1500 or higher, again, it won't drop at all.... It's just that it will start out at 13.8, which bugs me.
I've read this has to do with the ECU telling the alternator everything is fully charged (in it's opinion) and it doesn't need to work so hard, especially when hot, so as to preserve it's own life span. Whatever, I'd prefer 14.5 at all times, even if it did die a year or two sooner
lol
Long story short, hot weather / a hot alternator, and what my ECU considers to be a "good enough" charge, causes my voltage to run at 13.8. Instead of 14.5. While beating my system has almost zero effect on my voltage.
I've looked at a ton of those 30, 60, 100Kwt+ stereo systems... I think like "most" of them
lol, and yes, lots of them tend to go the "bunch of" batteries rout... Or the few big, crazy expensive lithium rout, and yes, that can work.
But again, I know it's possible to run those kinds of systems with few to zero actual batteries... Not even lead acid, let alone lithium. One just needs to make enough amps to begin with.
BTW, it would take too much explaining here, but I know of a way that a strong vehicle... A big truck, or SUV, could make like 6000 amps or more ! And btw, this is enough amps to make 87,000 watts at 14.5 volts continuous !
Anyway, 20 lithium batteries wouldn't help my system, because I'm able to stay at max voltage now