I am wondering what kind of alternator I need (how many amps at idle), for a system with four 12's and amped front components (1900 watts true RMS) and a 600 amp power inverter also installed. There will be a secondary battery (also why I need the beefed up alternator) and a 5 farad cap (should I go for a higher farad rating?). Thanks

 

You need about 1 farad for every 500W rms of sub power, as for the alt. install as big a one as you can afford, keeping in mind to make 1900W rms takes 200A plus, but the average draw is probably less then 50% of that, so 100A your stock one is 60A-70A, if you can find a 175A-200A alt. that you can afford do it, otherwise anything bigger then stock is better then nothing.
Here is a hint, run 2 fused power cables to the amps use one for the high-pass and the other for the low-pass, [sub amp(s)] install the cap(S) only on the sub amp power cable, [as close to the sub amp(s) as possible]

Are you going to be playing the system for long periods of time without the motor running, if so add a second batt. if not, you do not need the extra batt. 94

 

here is the thing. I already have an optima yellow top deep cycle for a secondary battery and a 280 amp at idle custom spooled alternator ($350), but I am selling the Integra and getting a 300zx twin turbo, and will need to get an alternator for that. I am wondering what the minimum alternator is that I should get with music on loudly at idle for maybe 15 minutes at a time and be able to juice a 400-750 amp power inverter

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by CrazyModGSR &raquo;</TD></TR><TR><TD CLASS="quote"> I am wondering what the minimum alternator is that I should get with music on loudly at idle for maybe 15 minutes at a time and be able to juice a 400-750 amp power inverter</TD></TR></TABLE> A 400-750 amp power inverter would be a pretty big unit, do you maybe mean 400-700 watt power inverter, what are you running with the inverter? 94

 

sorry, yes, 400-750 watt. I was writing that post after working for 15 hours straight and quite tired. I may be using fog machine and a couple lasers

 

Well the same still applies, you can't go wrong with as big an alt. as you can afford, but to run the system your speaking of, a 200A one should work just fine. 94

 

200a should be a good choice.
I have a 135amp and im running around 1500watts total and gettin no dimmin.
With no cap either.