Problems with my sub and amp

Alright so I have 2 12 inch kicker comp vr subs and a jbl gtr 1001 amp, the 2 subs combined should put out 800 Watts rms, and my amp is supposed to be 1000 Watts rms. But I was having an issue where my subs were cutting out a lot at pretty low volumes and I’m trying to figure out what the problem could be. I also did not install everything myself so I’m not sure how everything was wired, and I’m a little new to car audio but I know the basics. So anyways once I noticed it was cutting out, I watched my amp while I hade it turned up to a volume it typically cuts out at, and I watched my amp to see if the power light was turning off and to see if the protection mode light would come on. Whenever it cut out the protection light would flick on and off. It does it less when I’m parked than when I’m driving. And when it was installed I was told the battery lost power 4 times, so the problem could be with the battery but if it is with the battery then why is the amp protection light coming on when it cuts out? Is it possible my amp just isn’t good enough? That wouldn’t make sense though because it’s a jbl, I heard great things about the amp, nothing but amazing reviews so I’m kind of puzzled. So if somebody could help me out it would be greatly appreciated, I tried to be as specific as I could be, I’m sorry if I left any info out.