Do I need an Alternator upgrade?

squaredeal91 · Dec 24, 2023

I upgraded the alternator on our 99 burb because I put in an electric cooling fan and alternators were only lasting a year or so then dying on hot days running a/c. Been good so far since.

RanchWelder · Dec 24, 2023

Upgrade it, along with all your wire sizes.
Defeat wire corrosion by improving the dismal engineering of a 5 year lifetime warranty wiring system.

The guys advising you to leave it alone drive their trucks for trash day once a month.
Climate, temperature and the age of your 16 gauge corroded wiring harness, play a huge roll on the load your electrical system endures.

The entire wiring system and the alternator was intentionally under powered and under sized to drive you up the wall with electrical failures.
If it ain't broke, and you leave it the same, it will be broke soon.

Thanks GM:
"I love planned obsolescence!" -Welder 12_24_2023

(Cough, cough, cough... Bull Shirt... cough, cough, cough).

xc_hide_links_from_guests_guests_error_hide_media

mavtricks71 · Dec 24, 2023

It turns out im gonna have to use the CS130 Alternator because it came with the 350 ho turnkey engine and my SI-12 wont fit in the bracket or at least i dont think it will. I no longer have the old Alternator.

fast 99 · Dec 24, 2023

If it aint broke don't fix it.

mrdap · Dec 25, 2023

Well here's my two cents...
Like everything else it depends on the application and how you're using it.
I don't like to see my voltmeter go below 13 volts.
With a standard 10Si or 12Si, when I'm at idle with AC on, blower on high all four headlight bulbs lit, windshield wipers running, it's going to go down below 12 volts at idle.
Personally I don't like that.
As as I take off down the road and the revs come up a bit, of course it's charging at over 13 volts again, so no worries.
If you're on the highway a lot and you're always running a reasonably high RPM it's going to charge great and you won't have troubles.
But if you want to sit there at an idel and still be at 13 volts, you're probably going to need a CS144.
I had originally decided to upgrade to a CS130 but they're limited to approximately 105 amps in stock form.
So I decided to bite the bullet and go all the way to the CS144.
It's got a larger case and a larger armature and therefore it has a design point of about 130 amps.
Approximately.
Now, not to say you can't get hot roded versions of 12 SI's, and CS130s that will equal that output. But I decided to go with an original stock CS144 which was designed from the factory to handle such high outputs.
There issues with retrofitting where you had a CS130 or a 10SI or a 12SI, because of the larger diameter case, but it can be done.
For what it's worth that's my two cents

MikeB · Dec 26, 2023

75gmck25 said:
Doesn’t sound like you need it. I’m using a 94 amp 12si right now, and never see any evidence that it’s not enough. I added the relay wiring kit to my headlights, which was the only high amperage thing on my truck.

Higher amp alternators are needed to support big driving lights, high amperage sound systems, etc.

I think that 94-amp 12SI would be more than adequate for most applications. I've used 10SI (50-60 something amps) and 12SI 78-amp alternators in a few vehicles over the years. All had HEI, most had A/C, but no power windows, electric cooling fans, or high-powered sound systems.

While GM was no doubt getting by with the least expensive charging systems, I have found the alternators they used for specific vehicles to be up to the task with headroom to spare; for example driving lights and modest audio amplifiers.

As for sound systems, you can't use a speaker's rated power handling capability to determine the sound system's average power consumption! And no way should you assume the system is always running at the rated RMS power. As for the ridiculously high "peak power" ratings on some equipment, they are meaningless.

If you haven't already done it, measure battery voltage at idle and then at around 2,000 RPM with all your loads turned on -- high beams, A/C, sound system, etc. I'd say you wouldn't want to see less than 12.6 volts, except maybe at idle.

An oldie but a goody: http://www.madelectrical.com/electricaltech/delcoremy.shtml

AuroraGirl · Jan 13, 2024

Snoots said:
The newer ADxxx models provide more umph at lower rpm's. If it works tho, don't fix it.

if he already has a cs130, AD230 is a drop in replacement besides a different pigtail for the rectifier. so OP if you ever need to replace your CS130 put one of these on it :

You must be registered for see images attach

They come in different ear arrangements for mounting on the brackets. I think your truck has a 6 inch straight across ear?

You must be registered for see images attach

something like this?

AuroraGirl · Jan 13, 2024

mrdap said:
Well here's my two cents...
Like everything else it depends on the application and how you're using it.
I don't like to see my voltmeter go below 13 volts.
With a standard 10Si or 12Si, when I'm at idle with AC on, blower on high all four headlight bulbs lit, windshield wipers running, it's going to go down below 12 volts at idle.
Personally I don't like that.
As as I take off down the road and the revs come up a bit, of course it's charging at over 13 volts again, so no worries.
If you're on the highway a lot and you're always running a reasonably high RPM it's going to charge great and you won't have troubles.
But if you want to sit there at an idel and still be at 13 volts, you're probably going to need a CS144.
I had originally decided to upgrade to a CS130 but they're limited to approximately 105 amps in stock form.
So I decided to bite the bullet and go all the way to the CS144.
It's got a larger case and a larger armature and therefore it has a design point of about 130 amps.
Approximately.
Now, not to say you can't get hot roded versions of 12 SI's, and CS130s that will equal that output. But I decided to go with an original stock CS144 which was designed from the factory to handle such high outputs.
There issues with retrofitting where you had a CS130 or a 10SI or a 12SI, because of the larger diameter case, but it can be done.
For what it's worth that's my two cents

If you went to a cs144, why not just go to a AD244? Other than the distance off the back of the case, same size. but the ad244 rectifier adds over an inch rearward to the size

AuroraGirl · Jan 13, 2024

Matt69olds said:
I swapped a 105 amp CS alternator onto my Olds 20 years ago, I have never slipped the belt.

The alternator came with a pulley for a serpentine belt. I was kinda worried about belt issues when I swapped to the V belt.

Thats because of the CS series "Charging System" what a creative name" feature that slowly ramps up output to meet demand instead of loads being applied as they come, so for example use an electric winch and your alternator will load that belt trying to output enough to keep up, but the cs130 will increase it over a short span so the shock to the belt and thus all driven accesories is lower

AuroraGirl · Jan 13, 2024

SirRobyn0 said:
Running a stock 78 amp alternator. Keep in mind when talking about up grading alternators, the higher the amperage the greater chance of slipping the belt in a situation where the battery is very low and the alternator has to charge it up.

Also, I just touched on this but CS and AD alternators do not turn on until the car has started even when used in their most simple wiring configurations. hwoever, if your truck takes a lot fo cranking to start it may begin to load before its started.(Its a predetermined amount of time and belt speed)

AuroraGirl · Jan 13, 2024

RanchWelder said:
Upgrade it, along with all your wire sizes.
Defeat wire corrosion by improving the dismal engineering of a 5 year lifetime warranty wiring system.

The guys advising you to leave it alone drive their trucks for trash day once a month.
Climate, temperature and the age of your 16 gauge corroded wiring harness, play a huge roll on the load your electrical system endures.

The entire wiring system and the alternator was intentionally under powered and under sized to drive you up the wall with electrical failures.
If it ain't broke, and you leave it the same, it will be broke soon.

Thanks GM:
"I love planned obsolescence!" -Welder 12_24_2023

(Cough, cough, cough... Bull Shirt... cough, cough, cough).

xc_hide_links_from_guests_guests_error_hide_media

Facts

MikeB · Jan 13, 2024

Nevermind.

Matt69olds · Jan 13, 2024

AuroraGirl said:
Thats because of the CS series "Charging System" what a creative name" feature that slowly ramps up output to meet demand instead of loads being applied as they come, so for example use an electric winch and your alternator will load that belt trying to output enough to keep up, but the cs130 will increase it over a short span so the shock to the belt and thus all driven accesories is lower

I did not know that. I have a Snap On load tester, next time I have the car running I may load test the alternator just to see what it does.

Since it’s below zero with snow falling, I’m betting it will be awhile.

BTW, welcome back.

AuroraGirl · Jan 13, 2024

Matt69olds said:
I did not know that. I have a Snap On load tester, next time I have the car running I may load test the alternator just to see what it does.

Since it’s below zero with snow falling, I’m betting it will be awhile.

BTW, welcome back.

thanks <3

AuroraGirl · Jan 13, 2024

Matt69olds said:
I did not know that. I have a Snap On load tester, next time I have the car running I may load test the alternator just to see what it does.

Since it’s below zero with snow falling, I’m betting it will be awhile.

BTW, welcome back.

My bad, I rememebered incorrectly. The alternator only has that feature if its activated by a BCM or a ECM) the AD230 which is the next generation after the CS130D alternators. Very similar in function and that, but those have the feature built in I described of taking time after starting before outputing to lower drag on belt on startup

Do I need an Alternator upgrade?

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