losing major voltage between both batteries....

[IgnoreMe 5,000+ posts]

voltage drops need to be 12v at the end of the circuit. if you are at 9v at the battery, you have 3v left going to your second "load"...the bad ground with excessive resistance.

 

[SeanDub 10+ year member]

well I charged it until my DMM read 14.7 volts. I turned the charger off and the voltage dropped down to 12 something so I didn't think it would work. However I turned it on and it played just fine. Played just fine since then until today and it started doing the same thing again. As soon as I turn the bass on it would kick in and out of protect.
So it worked just fine for about 2 days.

Well it's not a 14.7 volt battery. It's a 12 volt battery. My Kinetik 2400 sits at 12.7 volts, and there isn't a thing wrong with it.

 

[audiolife 5,000+ posts]

i would venture to say that a good percentage of second batteries that "go seemingly bad" are actually a bad connection somewhere. that is one of the main reasons people use a ground in back plus a ground back up front and or multiple runs.

 

[aaron7114 10+ year member]

well the other day I decided to check the resistance between the ground on the front battery and where I had the ground in the back. My DMM showed like 67.89 or something close to that. So I knew right away that had to be the problem. So I searched for a new ground, which was pretty dang hard seeing as my box takes up the entire back of my vehicle. But I finally found a ground that only had 0.05 resistance and I moved it there and its been playing fine since then!