heres what system i got so you can get a idea. i have 2 12 inch db drive wd 10,000 watt subs, 2 power acoustik a3000db 4500 watt class d digital amps wired at 1/2 ohm. i have already done the big three with 0 gauge wire and also added a ground in the rear of the truck. i can have the subs bumpin with the amp setting on the stereo at low but as soon as i turn the bass up the volts drop rediculously low. when the bass cuts out it raises the volts then goes right back down as soon as it hits again. it drops to like below 9. i have a wide range of alternators i can get. im planning on getting the 220 amp alternator but i can get a 105, 130, 160, 200 amp from the same supplier. i dont have my subs on all the time only on accassion so would the 220 be fine for normal driving and not raise the volts to high to cause damage. i will be placing a 250 amp fuse in line from the alternator to the battery.

 

find the biggest you can with the most amps at idle, most "cheap" HO alts will do 250 amp, but they require to be spin at 3500+ rpm, otherwise they put out maybe 50-60 amps at idle.

 

i'd go with the 200. go to big and you're gonna be damaging electronics if you're not draining the battery down with your stereo and other electronics.
just my 2 cents. its your truck so you choose

 

going to big is not going to damage anything, common misconception. read up on HO alt's before you say that next time.

 

it depends on what alternator you use. ever heard of overcharge. not trying to step on anybodys toes. got a buddy that has a k10 truck with a high output alternator and he has to run all his accesorys or he runs into problems. like i said its not my truck, just my input

 

he probably ran a external voltage regulator and didn't have it at 14v. or the alternator is bad and overcharging. overcharging can happen on a stock alternator too, not just a HO.

 

Yeah, you have to have something messed up for it to overcharge. With the field regulators that are used, you can basically turn an alternator off through commands from an external control (PCM in newer vehicles).

 

alright i'll let him know and see. i'll have to check it out

 

I am thinking you may need a battery or two near the back for some extra capacity until that alternator can catch up. That an a large cap for that hard hitting bass.

I am running just an old Legacy LA-1020 (Ducks and Runs) that I bought new 12 years ago and it is a tank but it kicks the **** out of my Jimmy at idle also and it is only rated for 800 watts.

 

2 PA3000's @ .5Ω with stock alt and no extra batteries..... I would suggest a 250amp alt from Mechman, really good idle output. Might want to think about a few extra large batteries in the back as well. Otherwise pretty soon those amps will let out the magic smoke.