: Voltage moving up and down?



John P
04-03-13, 03:43 PM
Hi guys, I've fitted a JL Audio amp running components. But now when I flash my lights, use windows or any other power, It cuts the sound out like its stopping power to the amp. It's a month old battery.
What is the problem? It's definitely only since the amp and components went in so must be related somehow.

Cheers

the cadillac man
04-03-13, 06:37 PM
Hi guys, I've fitted a JL Audio amp running components. But now when I flash my lights, use windows or any other power, It cuts the sound out like its stopping power to the amp. It's a month old battery.
What is the problem? It's definitely only since the amp and components went in so must be related somehow.

Cheers

Check the grounds as it sounds like a ground loop

John P
04-03-13, 09:11 PM
Where are the grounds? The ground for my amps fine. Hoping its not the alternator!

It starts and runs fine, just when I use additional stuff it drops the sound and the dash lights dim slightly. But it's only stabs of power it doesn't like. If my full beam is on, it's fine, but if I just flash it doesn't play ball.

the cadillac man
04-03-13, 11:09 PM
Where are the grounds? The ground for my amps fine. Hoping its not the alternator!

It starts and runs fine, just when I use additional stuff it drops the sound and the dash lights dim slightly. But it's only stabs of power it doesn't like. If my full beam is on, it's fine, but if I just flash it doesn't play ball.

Could be battery or the alternator I would have both tested to be safe as it sounds like something isn't right

I was meaning the ground on the battery(it can get in bad shape if not cleaned)

6lbsofSound
04-03-13, 11:17 PM
Check the grounds as it sounds like a ground loop

A ground loop is back feed or whine that is audible through the stereo.

It sounds like the charging system doesn't have enough amperage to support the stereo, which is why the voltage fluctuates. Take a volt meter and measure the voltage drop to see how low it goes if it drops below 12v JL amps will shut down.

You can google the big 3 and try that, second option get a capacitor to help level out the voltage fluctuations. Or third get a higher amperage alternator.

the cadillac man
04-04-13, 12:10 AM
A ground loop is back feed or whine that is audible through the stereo.

It sounds like the charging system doesn't have enough amperage to support the stereo, which is why the voltage fluctuates. Take a volt meter and measure the voltage drop to see how low it goes if it drops below 12v JL amps will shut down.

You can google the big 3 and try that, second option get a capacitor to help level out the voltage fluctuations. Or third get a higher amperage alternator.

The low power shut down feature is on many amps except maybe the really cheap/no name brand amps

I don't know why I said ground loop(I guess my mind was elsewhere) but symptoms like this can be from a loose battery cable connection(since its effecting both the lights and amps(the trucks computer modules will shut down unneeded load if underpowered to keep the truck running as long as the PCM can power the fuel pump and relay)
I know as my car did this once(I had left the ground cable loose) I was listening to the radio and went to start the car and everything went dead I wiggled the ground and it started without a issue