jahnetik

I have an 01 A4 1.8T.....Just installed one 80Wx4 4 channel amp (i think thats the wattage) to run my speakers and a 500W Mono amp to power my 12 inch Type R which is 1500W max. I have a top of the line wiring kit install so there's no worries there.

My question is can my OEM alternator and battery (550 CCA) handle the new strain from my audio system? My Halogens have a subtle blinking to the bass and I can feel a slight vibration now to my car. My Halogens also blink if my ABS kicks in or I'm on bumpy terrain. My buddy thinks I need to run a new, thicker ground wire to my battery. What do you guys think?

FuriouS

You're fine running 2 amps like that on stock alt.. If anything, upgrade your battery to an Optima or similar and you'll be fine. Beefing up the ground is recommended.

ls03od

I agree with FuriouS that your stock setup should handle your new sound system. But I don't see a need to upgrade your battery unless you listen to your system without the car running or if your current battery is weak and needs replacing. The battery is a source of power when the car is off but when the car is running the battery becomes a load on your alternator, just like all your other accesories (ie. sound system, ABS, etc). IMO, Optima batteries are not worth the extra money. I have had two in my car and they did not last as long as others I've used.
I would make sure that the ground for your amps are made with large gauge wire, all amps ground at the same location, that the ground location is where there is thick metal, and make sure to scrape away any paint. You should be grounding to bare metal. One thing that many people don't do is upgrade the ground at the battery. Replace the factory ground wire with the same thick gauge you used to ground yours amps.
If your lights are still flicking, and it bothers you, you can add a capacitor in-line with your power to your amps. I would look for a capacitor of about 1 farad in size and try to put it in-line as close to your amps as possible. Some people argure the benefits of a capacitor in a sound system, but it will get rid of your flickering headlights. The flickering or blinking doesn't mean that anything is wrong, but it can't be a pain to look at.

FuriouS

If your lights are still flicking, and it bothers you, you can add a capacitor in-line with your power to your amps


This is exactly why you put the Optima in. Caps are Crap.

Other then this, i think we see eye to eye

ls03od

In my experience, going to an optima battery or any other battery never helped with flickering lights. Once the car is running, the battery provides nothing to the car other than being a load on the alternator. With the alternator putting out 14.4 volts and the battery sitting at about 12.5 volts, the only way any accessory will take current from the battery is if the alternator voltage drops below 12.5 volts.

A good way of thinking about this is what happens if you turn on your headlights with the car running and with the car off? The lights are much brighter when the car is running vs. off. With the car on, the lights are getting powered by the alternator, and with the car off the current comes from the battery. The lights flicker usually during heavy bass notes when the amps are drawing lots of current from the alternator. At this point the voltage 'sags' below 14 volts and so the lights are getting less current. The only time the battery comes into play is if the voltage drops to 12.5 volts. By then, the lights have definitely dimmed.

I've seen this happen where an alternator is on its last legs and the voltage was dropping to 11.5 volts and eventually, not only did the alternator die but it ended up killing the battery too.

I agree with you that caps are crap for car audio, but I've used them in my installs because I can't stand flickering headlights.