What size alternator?? - Chevelle Tech
Electrical & Wiring Troubleshooting electrical problems.

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post #1 of 13 (permalink) Old Jun 24th, 18, 7:58 AM Thread Starter
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Kurt
 
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What size alternator??

Finishing up my "66, and need to buy an alternator....
I have A/C, electric fans, Dakota gages, but no big sound system
or extra lights ....
What size alternator do you guys recommend?? Brand ??

1966 SS coupe .....
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post #2 of 13 (permalink) Old Jun 24th, 18, 8:27 AM
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Re: What size alternator??

I have basically the same setup, I went with a powermaster 140 amp. Efans draw a bunch of current on startup. I think the idle current is around 100
amps. More than enough to get the job done.
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post #3 of 13 (permalink) Old Jun 24th, 18, 8:38 AM Thread Starter
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Kurt
 
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Re: What size alternator??

Thanx John, Thatís what I was thinking....
Iím assuming big is better ....

1966 SS coupe .....
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post #4 of 13 (permalink) Old Jun 24th, 18, 10:23 AM
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Re: What size alternator??

Yes, IMHO bigger is better when it comes to alternators. I like the cushion they provide.

Which efans are you using? Iím running a set of 2002 windstar fans, I started out with 30 amp fuses, both popped at the startup of the fans. Went to 40 amp, same thing. Finally settled on a pair of 50 amp auto reset breakers, no problems since.
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post #5 of 13 (permalink) Old Jun 24th, 18, 10:53 AM Thread Starter
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Re: What size alternator??

Quote:
Originally Posted by SSJohn View Post
Yes, IMHO bigger is better when it comes to alternators. I like the cushion they provide.

Which efans are you using? Iím running a set of 2002 windstar fans, I started out with 30 amp fuses, both popped at the startup of the fans. Went to 40 amp, same thing. Finally settled on a pair of 50 amp auto reset breakers, no problems since.
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post #6 of 13 (permalink) Old Jun 24th, 18, 11:33 AM
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Re: What size alternator??

Quote:
Originally Posted by thebeast View Post
Finishing up my "66, and need to buy an alternator....
I have A/C, electric fans, Dakota gages, but no big sound system
or extra lights ....
What size alternator do you guys recommend?? Brand ??
we need to touch on the wiring needed to handle 100-140amps
do you still have the stock harness?
are you going to go with 1-wire or the stock 3-wire??
most likely you would go internal regulated with that high of amps???

68-Malibu 427bbc/t4oo/3.73-12bolt/pro charger f1-r
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post #7 of 13 (permalink) Old Jun 24th, 18, 11:39 AM Thread Starter
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Kurt
 
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Re: What size alternator??

Quote:
Originally Posted by VinceS427bb View Post
we need to touch on the wiring needed to handle 100-140amps
do you still have the stock harness?
are you going to go with 1-wire or the stock 3-wire??
most likely you would go internal regulated with that high of amps???
Wiring harness is new..... Probably go 1 wire ....

1966 SS coupe .....
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post #8 of 13 (permalink) Old Jun 24th, 18, 1:51 PM
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Re: What size alternator??

Quote:
Originally Posted by thebeast View Post
Iím assuming big is better ....
Just to throw this out, alternators have an output curve in that at a low RPM they can only put out so much but then the higher the RPM's and the faster it spins the more output it can give.

On the Powermaster site, here are some numbers they provide (didn't see any charts but these are some numbers):

90A Max/75A Cruise/65A Idle
100A Max/90A Cruise/70A Idle
140A Max/125A Cruise/95A Idle
150A Max/125A Cruise/90A Idle
155A Max/135A Cruise/95A Idle
165A Max/145A Cruise/95A Idle

Even though you have a new harness, that harness was made to a specification that may or may not support higher output alternators.

You just want to do things right, have it reliable, and also have it safe.

Jim
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post #9 of 13 (permalink) Old Jun 24th, 18, 2:43 PM
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Re: What size alternator??

Quote:
Originally Posted by thebeast View Post
Wiring harness is new..... Probably go 1 wire ....
A three wire alt will actually perform better than a one wire, reason being the ďsenseĒ wire can be run to the main electrical junction under the hood. The alt will maintain ~14.2v at that junction, so there is less voltage loss throughout the rest of the system.

With a one wire alt the voltage regulator gets the voltage reading from within the alt and maintain ~14.2v output from the alt. Any additional load on the system, including voltage drop through the wiring up to the main junction block is not recognized, resulting in dim lights, weak ignition, etc.

Below is a pic of my junction block, mounted on the firewall. It runs at ~14.2v, no matter what. This means my lights are brighter(those would have been ok anyway, I run relays on my lights), but more importantly the fuse box (just a few inches of wire away) runs at full power all the time or very close to it. Dash lights, a/c fans, ignition, etc. all good.

I modified the circuit found on this website to work with my particular specs:
MadElectrical.com - Mad Enterprises
I called and talked to Mark for three hours straight, he is a wealth of info.
All that being said, I now have a bulletproof electrical system.
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post #10 of 13 (permalink) Old Jun 24th, 18, 3:01 PM
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Re: What size alternator??

3 wire alt system will serve you best.

Catalog part 1

Catalog part 2

Catalog part 3

Catalog remote voltage sensing
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post #11 of 13 (permalink) Old Jun 24th, 18, 4:19 PM Thread Starter
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Kurt
 
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Re: What size alternator??

Thinking back into the olden days, I remember the points on
my '63 SS had to be adjusted to correct the output... I remember the
dealer setting it "too high" which made the alternator (or something)
whine ..... This was 50+ years ago, and itís just a vague memory ....
Lots of good info here, and Iím going show and discuss this
with my engine builder ....
As you can probably sense, Iím pretty ignorant about this....

Thatís why I came to you guys .....

1966 SS coupe .....
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post #12 of 13 (permalink) Old Jun 24th, 18, 4:56 PM
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Re: What size alternator??

Quote:
Originally Posted by thebeast View Post
Thinking back into the olden days, I remember the points on
my '63 SS had to be adjusted to correct the output... I remember the
dealer setting it "too high" which made the alternator (or something)
whine ..... This was 50+ years ago, and itís just a vague memory ....
Lots of good info here, and Iím going show and discuss this
with my engine builder ....
As you can probably sense, Iím pretty ignorant about this....

Thatís why I came to you guys .....
Maybe thebeast can be led to water and he will drink.
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post #13 of 13 (permalink) Old Jun 24th, 18, 6:20 PM Thread Starter
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Kurt
 
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Re: What size alternator??

Quote:
Originally Posted by DUTCH MAX HEADWORK View Post
Maybe thebeast can be led to water and he will drink.
I will drink from the vast knowledge vessel that guru's here provide ....

1966 SS coupe .....
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