I'm replacing the entire system with a different HU, Focal speakers and two 400w Focal amps and a Focal sub. Do I need to use a capacitor and some kind of extra battery? The actual install won't be until Spring, but I want to get all the stuff ahead of time. Should I also get an Optima type battery?

 

I have 2 10 inch JBL W1V2, 2 Alpine door speakers (one in each door) 2 Alpine 6X9s 1 500W Alpine Amp and another amp (I'm not sure of the wattage). Anyway with all of this a capacitor isn't needed though recommended (I'm currently not using one). I did have to replace the original battery with something much stronger. Good luck with everything.

 

It depends on the current/amperage draw of the focal amps. You probably won't need a cap but a heavier battery is a good idea. I've run quite a bit of power on stock charging systems without caps and just an upgraded battery and been fine much more often than not.

Unless money is no object, it wouldn't hurt to get the system installed and see where you're at. It won't hurt anything but your wallet to upgrade the battery but it may not be necessary and it's easy enough to do after the fact.

 

An extra battery will always be cheaper and out perform a capacitor. Sears Die Hard Platinum series is a very good battery

 

Capacitors = waste 99.9% of the time.

That .1% is people trying to look cool in shows.