Trying to figure out the capacity of my alternator

SSTJ

SSTJ

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I'm trying to find out the capacity of my alternator: 1997 SE 2.5L. I know that most TJs come with the 117 amp alternator, but I've read that some of the SEs come with a weaker one. Plus, 1997 was an odd year.

Anyone know? I checked my owner's manual but found nothing. I tried the FSM thread but it's missing the 1997 copy.
 
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The '97 manual is in there, it's all the way at the bottom for some reason.
 
Thanks to @qslim for correcting me. Here's what I found in the 1997 FSM.

Screen Shot 2021-04-13 at 11.43.38.png

Looks like both the 81 amp and 117 amp came as options in both the 2.5L and 4.0L engines. I'm going to bet/assume that my little bare-bones SE came with the 81, but will double-check the part number when I can.

Funny that I often hear 75 and 90 thrown around as sizes for some SEs. Instead, those appear (final column) to be the minimum test amps, not the rated SAE amps (middle column).
 
I think the higher amperage rating was a function of a 'cold weather package' or something like that. You might be able to find that info on your build sheet, there are links for that kicking around here somewhere.
 
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SSTJ said:
Thanks to @qslim for correcting me. Here's what I found in the 1997 FSM.

View attachment 243454

Looks like both the 81 amp and 117 amp came as options in both the 2.5L and 4.0L engines. I'm going to bet/assume that my little bare-bones SE came with the 81, but will double-check the part number when I can.

Funny that I often hear 75 and 90 thrown around as sizes for some SEs. Instead, those appear (final column) to be the minimum test amps, not the rated SAE amps (middle column).
Click to expand...
2 reasons...
when getting a replacement alternator all the parts houses use 75 or 90 rating on your platform. The minimum alternator output. So it just becomes common speak.

The two ratings mean...
Amp output @ 6000 rpm
This is your SAE #

The minimum test amps is @ idle speed in most cases.

In other words a baseline or bare minimum amperage output.
 
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CodaMan said:
The 4th item listed on my 2004's build sheet is 117 Amp alternator so take a look at your build sheet.
Click to expand...

Nice, thanks.

I don't yet have one. Anyone recommend a site (ideally free, ok if not) to get one using my VIN? Mine is a 97, and I hear that pre-98 models are sometimes harder to get.

Edit: Nevermind; Google is my friend.
 
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Sweet, my build sheet says I have the 117. I'm, pleasantly surprised. Might still double-check the part number sometime.
 
This is interesting - here is a screen shot from my '98 FSM. My build sheet says I have the 81 amp. However, I've added A/C, cruise, hardtop, winch and stereo with sub so I'm thinking I may want to upgrade to the 117 (pretty sure it would have come with that size if those options would have been included from the factory).

Seems like the "117" amp is really shown as a "90" amp when looking at new ones, as @Rubicon88 mentioned. This is the one I was looking at from RockAuto: Denso 2101003

1618433303294.png
 
HuskerJeep said:
This is interesting - here is a screen shot from my '98 FSM. My build sheet says I have the 81 amp. However, I've added A/C, cruise, hardtop, winch and stereo with sub so I'm thinking I may want to upgrade to the 117 (pretty sure it would have come with that size if those options would have been included from the factory).

Seems like the "117" amp is really shown as a "90" amp when looking at new ones, as @Rubicon88 mentioned. This is the one I was looking at from RockAuto: Denso 2101003

View attachment 243808
Click to expand...
You want to know the minimum amp output rated at idle.....
Unless you drive down the road@ 6000 rpms all the time the peak is really not important.

Can your alternator maintain all your equipment at idle? That's the important part. The faster they spin they will put out more but does you no good if you're starving for amps at idle and or low rpms.
 
HuskerJeep said:
This is interesting - here is a screen shot from my '98 FSM. My build sheet says I have the 81 amp. However, I've added A/C, cruise, hardtop, winch and stereo with sub so I'm thinking I may want to upgrade to the 117 (pretty sure it would have come with that size if those options would have been included from the factory).

Seems like the "117" amp is really shown as a "90" amp when looking at new ones, as @Rubicon88 mentioned. This is the one I was looking at from RockAuto: Denso 2101003

View attachment 243808
Click to expand...

Interesting indeed. I was surprised that mine came with the 117, since it is otherwise a bare-bones SE from the first year of the TJ. But I checked the part number and I do indeed have the 5685.

And yes, it is strange that the idle/test amperage is different in your screenshot than it is in mine, even for the same part numbers.
 
SSTJ said:
Interesting indeed. I was surprised that mine came with the 117, since it is otherwise a bare-bones SE from the first year of the TJ. But I checked the part number and I do indeed have the 5685.

And yes, it is strange that the idle/test amperage is different in your screenshot than it is in mine, even for the same part numbers.
Click to expand...
Husker's manual is a misprint on the 57 amps. It should say 75 amps like yours.

The 88 amps versus 90 amps... the FSM gods might have rounded up before and it always was 88 amps but rounded up to 90..?.. on yours but on Husker's they just used 88.
2 amps is negligible.
 
Rubicon88 said:
Husker's manual is a misprint on the 57 amps. It should say 75 amps like yours.

The 88 amps versus 90 amps... the FSM gods might have rounded up before and it always was 88 amps but rounded up to 90..?.. on yours but on Husker's they just used 88.
2 amps is negligible.
Click to expand...
I thought that same thing, so I pulled the '99 FSM and it also says 57. Maybe they just kept copying over the mis-print.

1618502809274.png
 
SSTJ said:
Interesting indeed. I was surprised that mine came with the 117, since it is otherwise a bare-bones SE from the first year of the TJ. But I checked the part number and I do indeed have the 5685.
Click to expand...
The higher 117 amp alternator is included on all TJs with A/C, does yours have that?
 
Darn, editing this whole post because I din't read the thread carefully.

I have a 1998 Jeep TJ Sahara 4.0 with AC.

The FCA build sheet says it had a 117 amp from the factory

And indeed 5600 5685 is what is on my Jeep.
PXL_20210511_205751634.jpg


That Denso 5600 5685 is now superseded by part 210-0130 which they claim is OE equivalent for 56005685
https://www.densoproducts.com/denso-210-0130-remanufactured-alternator
And indeed that, or its equivalent is the correct part.
 
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SSTJ said:
Thanks to @qslim for correcting me. Here's what I found in the 1997 FSM.

View attachment 243454

Looks like both the 81 amp and 117 amp came as options in both the 2.5L and 4.0L engines. I'm going to bet/assume that my little bare-bones SE came with the 81, but will double-check the part number when I can.

Funny that I often hear 75 and 90 thrown around as sizes for some SEs. Instead, those appear (final column) to be the minimum test amps, not the rated SAE amps (middle column).
Click to expand...
If your SE came with A/C it definitely came with the 117 amp alternator.
 
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