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Old Nov 7, 2007 | 10:32 PM
  #1  
JD_F250's Avatar
JD_F250
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From: McFarland, WI
Alternator question

Hey everybody. This time im wondering about my alternator. I need to know the amperage output?? I think thats what it called. Basically I need to know how many amps my alternator can handle. I want to install some off road lights and need to know if she can handle it. Its an87 F250 with a 6.9L IDI. All stock motor. Thanks for the help in advance.-JD
 
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Old Nov 7, 2007 | 11:03 PM
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Dave Sponaugle
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From: Nutter Fort, WV
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Probably 75 amps if your truck has AC.
But from my snow plow use I can tell you if you are running the engine slow which a diesel is so easy to do in, the alternator can not keep up.

I upgraded to a 150 amp for a little more money at replacement time.
 
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Old Nov 7, 2007 | 11:05 PM
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matts156
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From: New Jersey
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The factory alternators were 65-75 amps, with a heavy duty version that developed 100 amps. Look for stamped numbers in the casing, you should see a 65A or something along those lines somewhere on the back of the alternator. You might have the 100A unit because of the diesel engine.
 
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Old Nov 7, 2007 | 11:09 PM
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JD_F250
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From: McFarland, WI
OK im gunna go look right now. Thanks for the quick responses. I picked up a baja light bar that looks pretty good on the truck. It has 4 mounting tabs for lights and i found a couple of deals on lights. I would like the 130w set because well more is better. Theres also 100w sets but. you can never have enough light in the desert. What do yall think?
 
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Old Nov 7, 2007 | 11:17 PM
  #5  
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JD_F250
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From: McFarland, WI
Well I looked and theres no markings. I should have mentioned that the truck does NOT have AC. I see that its a motorcraft but thats all it says.
 
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Old Nov 8, 2007 | 03:34 AM
  #6  
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PLC7.3
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From: Manitoba
You should first think about........this mod.
https://www.ford-trucks.com/article/...r_Brights.html
 
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