is a 140 amp alt, really neccesary, or even 100 at that... why would you need that much.... just wondering bc im looking to by a new one...

and also... my stock alt... which i think is a 45 bc i have ac... will it be able to run the car, my electric fan, and a new stereo

 

Have you been having problems with your battery being low, lights dimming when idling, or the Alt needle always displaying discharge? If there's not been a problem, no need to upgrade.

If you plan on upgrading your car by adding amps, fans, EFI, etc...then you should consider a higher amp alt. Figure out what you're going to need and then select.

Typically, 100+ is overkill unless you're really running a high power stereo.

 

+1

 

I had the stock alternator on my car since I bought it a few years ago. It finally died on me this summer and it wasn't fun. It died in the middle of a busy Broadway, luckily I was able to push her to the side without incident, embarrassing though. I figured it was due to my stereo system. Although it's not super high powered, I'd say it's in the medium range, it was enough to fry the stock alternator. I went for the more expensive 100amp alternator from Summit so I wouldnt ever have that problem again. To me it's worth it. I think it might be worth it to you also since you also have A/C and an electric fan in addition to a stereo.

 

Alternator amperage is like a mechanical pumping unit, the more it CAN pump, but the less it does pump, the longer it lasts. If you have a higher amperage alt but are drawing a small amount of current through it, it doesn't get as stressed, stays cooler and lasts a lot longer. Bigger amperage may be overkill, and you spend more on the alt, but buy it less often. I have a 140a on mine, and don't expect to be replacing anytime this decade. It's also good to know that if you put a bunch of electrical crap on it, you have the amp to feed it, though our old cars have a very small electrical demand

 

ok so what do you guys think i sould get... ill be running a new style ac unit, an electric fan, and a new cd player with a 600 watt amp and sub.. what do i need to run all of this with out having to worry about it burning out

 

I would say get the big alt. That is what I did. Right now I am not pulling a lot of current, but I am adding the head unit and amp (440 watt) in the next couple of weeks, and plan on adding the electric fan and maybe an electric fuel pump this winter. I don't want to worry about juice.

I got a PA Performance one. It isa little more expensive than the Summit one I think.

 

I havea stock alt with a 22oo watts stereo,electric fuel pump and no problems and a 2nd batt.But i do think a higher output will charge both batts faster.true?