rule of thumb is to have an alt that can provide at least 1/3 the maximum current draw for your amps..... less then that and you will probably have severe voltage drop.....

My alt makes about 120ampears... my amplifiers can definatly pull 200+... no issues on the highway but once you hit a stop light voltage drops pretty hard.....

 

bought a 180 amp alt from sva power products. this thing puts out 80amps at idle. had to make bracket to fit it in my car-2002 hyundai elantra GT.
running 1/0 gauge all around-including "big three". three blue top optimas and two 1farad caps. voltage reads 14.9 at idle. dips to 12.5 with system cranked. gonna run more power wire in spring for less voltage loss.
cheers

 

the easiest way to get a high amp alt is to get a rebuild. Most of the time when u get a rebuild or from a store, the only time your gonna feel the diff in amps is aroung the 3000 - 5000 rpm range. At that point u will get near full draw from the alt for charging up caps and bats. I could be worng

 

109 amp alternator , 560 cca maintenance free battery . my amp only draws about 50 amps .

if i needed more i have a 240 amp 12v sitting around i could build a mount for or put another 109 in since i have a spare . not like its hard to build a mount

 

Depends on who you buy it for. Some vendors (like Iraggi alternators) make their alts for high idle amperage (ex, 200 amp alt I was looking at puts out 100 amps at idle). If properly taylored to your needs, a h/o alt can be very helpful.

 

In my experience- rebuilt alts give less idle amperage than the OEM alt. You will only gain from the rebuilt when the engine rpm's hit 2000 up. When inquiring about a rebuild tell them you want a higher amperage at idle.
cheers

 

the only thing that they dont replace on a rebuild is the housing . the diode rectifyer bridge should be set the same as the oem if its adjustable , a rebuilt shoudl be jsut as good as any other .