alternator problems

[mikey5912]

I had my alternator built to 250 amps and a idle it charges a 11.5 volts and the shop that built I said that's normal but I cant have nothing running at idle of my radio shuts off but once my rpms go up above 1500 it starts charging at 14 volts is this normal or is my alternator messed up

my audio im running is not big just 1 10 in Rockford t1 on a 1000 watt nitro amp so nothing big to bring the volts down

[Skullz]

Normal for a modified stock alt, the best you can do with it is get a smaller pulley and hope it brings the rpm's up high enough to charge at idle.

[mikey5912]

put a smaller pully on and didn't do anything different my old car I had the alternator built to the same specs and had no problems and that car the system was way bigger

[Guest DC Power Kyle]

Year, make, model, engine of the car that's having issues?

Also, year, make, model and engine of the previous vehicle that had no issues?

[mikey5912]

new car is 99 Pontiac grand am with a 3400 motor in it im running one 10 in Rockford t1 with a nitro 1000 watt amp

old car was a 94 chevy beretta with a 2.2 in it I was running 4 15 in Rockford p2s on 2 Rockford 1000 watt amp

[Skullz]

It is possible you had an overdrive pulley on the crank which would spin the alt faster.

[mikey5912]

I just got the car a month ago and not sure what pullys are on it I had the alternator built cause it was bad

[Kyblack76]

Built by who?

nevermind..

Ill build you a alt that can do 578 amps at idle.. Send paypal info...

[mikey5912]

I wish I just went to mechman in the first place but I went to a local shop that a lot of people said was good its called hanks in Tavares fl