Depends on what size alternator you already have, but for most vehicles I'd say 1400 watts would warrant one. A cap may help how your system sounds slightly, but if your existing alternator is lacking a cap is no substitue for a higher output replacement and could actually make things a bit worse.
If you have a domestic vehicle this is fairly inexpensive place to start looking:
fuel pump, electronic ignition, etc.. all draws power. to be safe, figure 80% of your stock alternator rating is used by the car's systems, and add from there for a stereo system to calculate a HO alternator size you need.
Ok question? should i run my jl 500/1 or my zapco referance 500m class a/b mono amp??? the zapco does 500rms at 4ohms and is underated and can do 538rms and at 2 ohms it can do 700rms. The fuse rating is 40A for the zapco though. Which one of these amps whould be more efficiant if i run it to a avalanche 15 800 watt subwoofer.????? my stock alternator is 80 amps and im also running my ppia300.2 for componants.. and i will use my batcap 800 stereo battery in the back..thanks
I am going to be hooking up a class D amp that is 1500 watts rms. Will i need a HO altinator, or i can i ge by with a capacitator? I have a stock altanator in a 2000 ford ranger, i have no clue how much power it puts out...?