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how many amps is the stock alternator?


16psibrick

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  • 2 weeks later...
How many watts rms can the stock alternator support without overstressing it and shortening its life? Also how many watts can it support without constant headlight dimming? I'm guessing they will just dim at high volume and if i keep the volume down to a lower level like i usually do dimming won't even be an issue even running 800-900 watts like i plan on doing.
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  • 1 year later...
It is 110 amps.

 

My limited research suggests only 70 amps... for my '05 2.5i.

 

I'd like to find out definitively because I need to upgrade either my battery (stock sucks particularly in colder weather and I will be subjecting it to a much colder climate this winter) or my alternator to help address the dimming I get when playing the stereo loud...

 

I was referred to this place: http://www.maniacelectricmotors.com/20allal11.html

 

and was just going to go with the 110 they sell as I thought it would be a nice upgrade over my 70 amp unit.

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I would be impressed if the factory Leggy alternators broke the century mark, most makes come in between 60-90 amps. High-current alternators make a world of difference, well beyond anything that a cap or new battery can hope to achieve.

 

A battery is like a resevoir, a cap is like a reserve pipe, and a high-amp alternator is like a tropical down-pour. The first is mass storage, the second is for instantaneous draw, and the third is a replenishing source. Without the rain the resevoir and reserve can't provide proper service.

 

These guys have been in the business of SPL competition for a while now, check'em out.

 

http://www.ohiogen.com/

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Yah, my understanding was stock was 70, some STI (Imprezas) came with 90 amp units.

 

The stock battery is quite weak imho and I feel I should definitely upgrade it to a deep cycle unit as I would like to listen to my stereo, watch a movie while parked etc and not have an issue plus the cold weather performance is definitely lacking.

 

On top of that, I definitely get dimming when the stereo is going hard so that points to the charging circuit = alternator.

 

(I've already done the 'grounding'/big 3 upgrade).

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an Optima battery is a welcome upgrade if you are having issues.

 

yah, thinking Yellow Top... going to shop around a bit for a good price.

 

What is the right model/size?

 

Also, there has been mention of Optima recalling batteries etc - a bad batch or what not perhaps. Just want to ensure I'm not getting old stock from a disreputable dealer etc...

 

:spin:

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  • 1 year later...
Just keep in mind folks 110A when the car is running at an RPM sufficiently high enough to spin it up fast enough. If you're at a light blasting your tunes and wondering why your lights are dimming you might want to consider turning it down to avoid damage (and to be polite :) ).
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Just keep in mind folks 110A when the car is running at an RPM sufficiently high enough to spin it up fast enough. If you're at a light blasting your tunes and wondering why your lights are dimming you might want to consider turning it down to avoid damage (and to be polite :) ).

 

 

By chance do you know at what rpm will the alt be running at 110A?:)

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