Topic: Alternator Upgrade for Elect Fan Conversion

[jonzjeepyj]

Looking to upgrade my Alternator for an electric fan conversion.  What amperage should I use and is there a cross reference for a alt that I can use from a salvage yard?  I would like to buy used if possible.   Possibly a 4.0L alt or somthing different.  Any help would be great.  I read the sticky on the conversion and it looks like I need at least a 120 Amp.  I have a 90 Amp now. 
Thanks,  John

[jfrabat]

Jeffy posted some junkyard options some time ago.  I chose the eBay route, and went with something like 160 or 170A... dont remember exactly.

[jonzjeepyj]

I'll look again and see if I can find the list.
John

[Jeffy]

http://4bangerjp.com/forums/index.php?topic=400.0

[Bounty Hunter]

I've used the 136A upgrade, easy install. PN 56027913.

[jonzjeepyj]

Thanks Jeffy, 
I found it.  Was the 136A Dodge Alt adequate enough for the extra amperage 
pull of the fan with additional accessories?  Was it a direct bolt on application?

John

[jfrabat]

I used my stock alternator for about a year or so with the e-fan, KC Slimlights fog lights (on all the time that the main lights are on), KC highlighters (onwhen the high beams are on), a kick ass stereo, and the AC (my AC fan is the biggest consumer of amps!) and it worked with everything on...  I only changed it as a precaution, but it was working (granted, when everything was on, the volts fell a little too low for comfort).

[Jeffy]

Thanks Jeffy, 
I found it.  Was the 136A Dodge Alt adequate enough for the extra amperage 
pull of the fan with additional accessories?  Was it a direct bolt on application?

John

The Fan doesn't pull that many amp on low and only pulls large amount as it just turns on.  You might be able to get away with using the stock 75A alternator.  I swapped out mine because at night with everything on, the alternator would kick in and literally whine.  My current 170A alternator makes more then 75A at idle so it's not a problem anymore.  It waws more of a piece of mind thing.  Not to mention, I have a winch.  My Warn will pull a max of 435A at it's 8000lbs limit.  Run headlights, parking lights, spotlights, CB, 2M Ham, Stereo, etc... and you'll get it even higher.

Was it bolt-on?  Did you scroll down that thread?  There is a write-up on the install.

[jonzjeepyj]

Looking at mine, I read it to be a 90A Alt. 
With that said, can I get away from upgrading? 
I have a wimpy stereo and two extra lights on the bumper.
just didn't want to run into any problems later on if the amp draw
was too large. 

John

[jfrabat]

Looking at mine, I read it to be a 90A Alt. 
With that said, can I get away from upgrading? 
I have a wimpy stereo and two extra lights on the bumper.
just didn't want to run into any problems later on if the amp draw
was too large. 

John

As I said, mine ran fine with the stock alternator (dont remember if it was 70A or 90A; I think it was 70A), but like Jeffy, I simply replaced it for my own peace of mind.  But I did use it for almost a year with no issues (I should point out that I do have the DC Controller, which reduces the amp load on start up because it controls the fan speed by using pulses and adjusts speed according to radiator temperature - the hotter it gets, the faster the fan spins).

[jonzjeepyj]

That was my next question,  How to regulate fan speed according to engine temp? 
Most people hook it up to the low fan speed with the start of the motor.  I wanted
to regulate it also.  Which fan did you use and how was it hoked up?

John

[jonzjeepyj]

I confirmed the part number.  it is a 90A Alt

Denso 56005685  1991 to present

My Jeep is a 1992 YJ

I think that it will be adequate to keep my battery charged after the fan conversion.
Thanks for the help and info Jeffy

John

[Bounty Hunter]

You should be fine with the 90A alt.

Here's a good fan controller, the FK35: http://www.dccontrol.com/0820.htm

[jfrabat]

You should be fine with the 90A alt.

Here's a good fan controller, the FK35: http://www.dccontrol.com/0820.htm

That's the one I use (FK35 with the Ford Fan), and I have not had any problems with it...  It only did not cool my engine once, and it was because I left the fan unplugged.   (can't blame that one on the controller!).

I connected it to the high speed fan wire, and connected the low speed fan wire to a relay.  Then I connected the IGN of the controller to one side of a 3 position switch and the relay to another, which means I now have OFF, ON (low speed through the relay), and AUTO (through the controller).  I did it so I would have a backup oin case the controller failed, but so far, I have not had a need for the ON part.

[Compstall]

I just picked up a 136 amp alternator off Ebay from a '98 Grand Cherokee.  Was happy to get it, only to find out that the new alternator has a 2-pin connector on it, and my 90-amper doesn't.  So now I have a nice 136-amp alternator that is of no use to me, unless there's some way around it...