Could my stero system be killing my car?

If this isn't the cause, might not be the right sub, but felt like the relevant place to ask.

I have a 2011 nisan altima, I bought it used with an aftermarket stero, amp and sub. I don't really know the specs on any of them, but I'm thinking they might be causing issues with my car.

For added context the alternator and battery are both new enough to be under warranty.

Occasionally, when driving around I'll get voltage dips, hard ones. All the lights, stero and heat will all 'dim'. These are more common on cold nights when I've got my brings on, heat cranked, and music on.

I did the test where you disconnect the battery with the car running, and it Immediately died. This was with the headlights off, and not playing any music. I know this generally means a bad alternator, but considering it's new, could this be the stero? I'm not super well versed with a/v, but from what I've been able to research the dimming with the stero might be related to lack of a capacitor to help even out voltage spikes, but would it draw that much power without actually using it?

I can get the specs from the original owner if that helps any