Bought a aftermarket HO alt, and it only does 100amp??

[Bump4life]

I just checked a stock alt, at idle no load (no heaters, ac, lights, wipers) about 15 amps of draw.

Still at idle heater, lights, windows being moved up and down, wipers and hazards on about 45-50 amps of draw.

Here a question though

Does a car pull more amperage at higher rpms?

Reason for question

At a higher rpm your fuel pump, injectors, coil pack and computer need more electricity to reach that rpm. Might not be a big increase in amperage draw but even if it's say 15 amps it can make a difference.

Say you have a 300amp alt with 280 amps if power draw between the car at an idle and the stereo being pushed hard. You rev the motor to 2krpms and it pulled another 15 amps. You are now at 295 amps if draw.

Now even if a alt can do the 300 amp on a test bench it can't do that in a car, specially once it gets hot. So now your surpassing the capability of the alt. So in turn voltage drop.

yes it does require more amperage once moving but not much. think of components that needmore, fuel pump, spark plug distributor thats all i can think of. its not too many. when i measured it wasnt a significant difference, the biggest difference is having your climate control on and even worse at full blaST. or a defroster.

and yea the alts rated 320 or 300 wont do that in the car at temp. some companies will tell you what it will do hot.

my alts i rate them at what they will do all day under the heat of the hood. sure people may think they are paying a ton for a "lesser" alt but its like buying an amp based off its max rating. most alt companies sell based on a max cold rating not the "rms" heated all day rating. food for thought.

[Guest]

I heard kylar put a stinger pulley wheel on powerbastards alternator

but that's none of my business

jk

[alaskanzx5]

Exactly

I know my alt from singer is a 250 amp unit. In the car hot I know it won't do that. It's has some effiency loss once its off the test bench and in a hot engine bay. That is life.