Big 3 and volts more unestable

[Gerson80]

Hi, so I had 2 wires 4AWG from +Battery/Alternator, 1 wire 4AWG from -Battery/Motor Ground and 1 wire 1/0awg from -Battery/Chassis, volts were OK and not too many unestability when playing, so i made modifications changing the 4awg from -Battery/Motor by a 1/0 wire, and added 2wire 4awg to the -Battery/Chassis of alternator, I was expecting to have a better volt stabiliy but what I found now is that the volt meter in the dash goes from 14volt - 11.5volt when I increase bass, before of this change it was also doing it but the volts didtn go that low, probaly it goes to 12-12.5volt the lower, is this normal if I added "better ground"???, in the case of subwoofer I hear that it hit better than before, just not sure if going lower in voltage is correct as the big3 supposed to improve that part, thanks.

 

PS I hope I explain correct what I want to say