flickering headlights

[Vikz]

I've recently fitted a sub and amp into my A3 but when i turn up the bass at night the headlights start to dim out alot. i've fitted a 1.2 farad power cap but the lights still dim out.

does anyone else have any suggestions?

thanks.

 

[AndyMac]

Ummm power caps are a total waste of money, really just a band aid solution.
Are you running the power for the amp directly to the battery?
If so then it sounds like you have either your battery on the way out or the alternator. How old is the battery? They only last about 4-5 years so I'd start here as it's a relatively easy & cheap fix.
If you're running the amp power off the heavy duty terminals under the dash then this is more likely to be the cause as other components run off these connections and the wiring won't be rated for a heavy current draw for an amp, so you'll get a voltage drop on both the amp and any ancillary components running off that supply.

 

[Vikz]

it's currently running off the heavy duty terminals under the dash. would it be better to run it straight off the battery? also i think the battery needs a change.

 

[AndyMac]

Yes definately, the wiring to those terminals is not rated to cope with short bursts of big current draw, and with all the electrics in the car running off them as well you'll be getting a voltage drop on the amp (distortion) as well as the headlights.
Wire it straight to the battery with an inline fuse near the battery.

 

[Vikz]

cheers AndyMac.