I have this hooked up to starter battery and stock alternator in my trunk. It's powering an Autotek Mean Machine 2000w rms amp. i was having extreme dimming and power issues so i need something to help out.
So i bought this along with a Power Acoustik 30 farad Cap to maintain constant voltage. All is fixed!! No more dimming and when turned up with the car on i never go below 12.5v.

if you have a stock alternator you need to give your system a break. Don't be blasting all the time because the alternator can't charge the batteries and provide the power all once!