Alternator ???

Which Alternator amp would you install in your Speedster if you had Air Condition? I have a 55amp Alternator now which is now charging my Battery. I know they sell 75amp and 90amp Alternators. Which one should I buy. I was thinking of the 90 amp. Any ideas???


Aloha, Kawika

I'd think the highered alts are for running big stereo amps , high wattage head lights and fog lamps. All you have on with AC is the blower fan(s).

if i could do it again, i would buy the 75 or higher amp alternator. i have the 55 and when i have my high beams on, heated seats going and my air suspension compressor kicks in - my headlights dim.

In the '60s alternators put out around 35-40 amps and powered most car very adequately....If you feel you must go bigger, I would recommend the 75 amp unit, as it takes less hp to turn that extra weight.(inertia) As stated, unless you are running some really power hungry equipment, the 90 and 100 amp units are overkill.... Just my .02

100 amp alt. a ground clamp, some Mig wire and you can do roadside light spot repairs ..I've seen tis tried and &%# it works.
Seriously, as Leon said 75 amp is more than fine.

you forgot the required beer.

i've almost spot welded by throttle cable linkage by accident with the car off - so i believe it!

Alan - that method is one of our off-road repair tricks!

Thanks guys for all the info. I ended up getting a 90amp Alternator with built in Regulator because I use my A/C all the time and my Stereo System.

Happy Holidays to All, Kawika

Crank it UP, Brah!!

BTW - your car is lookin hawt. i love the stance.

My Bosch died (55 amp) and I just bought a Bosch reman. replacement. They are getting hard to find; most of what I see offered nowadays is Chinese crap....

Timely as I have been thinking of this as well

Besides the normal electrical loads, I have a power amp and stereo, air-con on all the time, H-4 headlights, and a Megasquirt FI ECU. Spot lights will be in the future.

I have not added up all the loads, but thinking that 75 should be more than sufficient, but would the existing 55A do it?

Heated seats not required

Flux capacitor

I live in Thailand and while aspiring to a throwaway society, there are still shops here that rewind alternators, starters, and all sorts of electrical motors.

I wonder what the difference is between a 55 and 75A alternator - more windings, bigger magnets, or both?
Perhaps I can get mine rebuilt and hopped up at the same time?

Hi Robert,

Be prepared to show the electrical shop a sample. Third world electricians are great mimics, i.e, they can rewind a motor if they have the burned one as a guide. Perhaps you can check on line to determine the winding wire diameter, rotor type, etc. for greater output. If you can show a diagram, you're usually good to go, or ask in a rewinding shop if they have a burned carcass of a 75A that still has the burned parts inside. Best of luck.

I actually found a place back home to fix mine; since I didn't have to return the old one as core I'll just fix it and keep it around as a spare just in case. They tested the old alternator and sure enough it was dead.

And it turned out to be cooked ball bearings; fixed up and ready to go. I stored it to have as a spare.