Does anyone have an opinion on capacitors. I am planning to add a amp to my system 400 watts I believe drawing 30 amps. I have read that the stock alternators are not so hot but upgrading to a better alternators is too costly for now. Should I consider an Optima Yello battery instead of a cap. I have set of IPF driving lights and do not plan to add any other electronics for now

I've had a 400w amp in the truck for about 2 years now with no problems at all. I also run a 100w bazooka tube and 55w IPF fogs.

The normal rule is 1 farad for every 1000 watts, but adding a cap for 400 watts won't hurt. You could even get a 1/2 farad cap for cheaper and it would probably do the trick.

I ran my 600 watt amp off an Optima yellow top and it was fine, even while running fog and driving lights. The alternator was still kickin in a little to frequently for me though, so I added a 1 farad cap just for shits and giggles. No noticeable difference, but the piece of mind is there and it will be easy to add an additional amp if I ever upgrade again.

BTW, the yellow top kicks some serious butt. I run my stereo at full blast all the time while I'm playing bball or cleaning my carport or whatever and the battery has never died or failed to start, even after 4 hours of constant use. The biggest problem is my amp overheating after a while. Guess its time to add some fans.

My neighbor is runing a 15 farad cap off a stock battery and alternator and it only lasts a few minutes before the battery is dead.

Don't need a cap for that little power... You'll be fine.

Raise up the music all the way (in an open area with no people around), turn on the lights, and see if your car "dims" when the base hits. I'm running about 700watts and mine gives me a SLIGHT SLIGHT dim SOMETIMES on hard tones - not a biggie, and is something I can live with so I'll pass on the cap. Now if you want it for the looks - that's different.

I'm currently running a JBL 1200.1 powering 2 XTANT 10 inch subs and a US Acoustics 150X2 powering a set of CDT Audio 6.5 inch Comps up front off of the stock battery and alternator. The lights dim slightly but only on heavy bass notes with the volume cranked really high.