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Discussion Starter #1
Well a couple of months ago I got my truck back from being built and about 3 weeks ago my batter light came on in the truck I thought it would be my battery but got it swapped out and still had the same problem with low voltage , at idle it would go as low as 11-12 volts once even saw 10v on my aeroforce..I have a electric fan for the radiator and two for my heat exchanger and 255 pumps, interior I have 3 gauges and a touch screen that's about it, I've tried reading on the old forums on what kind of alternator I should go with but almost all of the posts were pretty old so I was seeing if there were any new suggestions out there and if a 200 amp would be best? But from whom and reputable manufacturer?

Thanks in advance
 

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Wile E. Coyote, Super Genius!
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Mine went out in 2014, same as yours. Thought it was the battery, but nope, alternator. I didn't have any huge load draws at the time, so went with a stock 130 amp from NAPA. I do have two HE fans in my garage now, but they will be wired into a toggle switch, for use at nap-inducing stop lights only. So I'll see if I need to get a higher output alternator.
 

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Discussion Starter #3
Yes from what I've been able to see the heatexchanger fans draw a pretty good amount... I've heard good things about the NAPA alternators as well...do they make 200 amp series?
 

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Cogswell Cogs
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Yes, NAPA does have a 200 amp alternator for our trucks.
NAPA also recommends buying their wiring upgrade too.
 

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2.9 Whipple E85R A1 Transmission
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My experience with these alternators...
The diodes get HOT from the current draw, they open and no longer have output. When the diodes cool down they close and work again.
So taking it off the truck and having it tested, it will show good.
How hot is your alternator getting?
My alternator consists of
70amp bridge rectifier
200 amp stator
Stock 130 rotor
HD voltage regulator
1.9" pulley
 

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Wile E. Coyote, Super Genius!
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It's nice to know that NAPA has the 200 amp as an option. I may consider one after I get the HE fans on. We'll see if it's necessary. As I said, they will be wired to a switch, and only be on at nap inducing stop lights. There's no need for them to be running once vehicle speed is north of, say 25 mph. If what Certified Drunk says is true, may not even be an option at all.
 

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2002 Ford F-150 Harley Davidson Edition
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Can any one put the part number for the 200 amp that works with our trucks from Napa because I'm probably going to end up having this problem as well when my build Is done. The upgrade wire kit too.
 

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Discussion Starter #8
Certified drunk I'm not shure on that I just took it to my auto parts store and got it tested and it failed so I couldn't tell you exactly...and about the upgrade wiring kit for the alternator, I installed the upgraded battery wiring kit from harley#356 I should be good with that right?
 

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Discussion Starter #9
My experience with these alternators...
The diodes get HOT from the current draw, they open and no longer have output. When the diodes cool down they close and work again.
So taking it off the truck and having it tested, it will show good.
How hot is your alternator getting?
My alternator consists of
70amp bridge rectifier
200 amp stator
Stock 130 rotor
HD voltage regulator
1.9" pulley
Also did you get yours custom made at a alternator shop?
 

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200 amp alternator seems to be the sweet spot for these trucks. I didn’t have issues last year, but I’m adding a remote bridge rectifier this year to help with the situation CD was describing. Should bring temps down and improve reliability. May even see less of a voltage drop during the summer months getting that heat out of the alternator.
537798
 

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local painter
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Looks clean man
Have you thought of using black cable glands instead of grommets to keep water out and secure?
the big ol cooling fan on the side may allow for a little water intrusion.. I'm guessing this would be mounted in cab?
 

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Discussion Starter #14
That looks good, also curious about where it would be mounted
 

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Wile E. Coyote, Super Genius!
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the big ol cooling fan on the side may allow for a little water intrusion.. I'm guessing this would be mounted in cab?
Don't drive it in the rain. No water intrusion. LMAO!
 
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Yeah my truck doesn’t get driven in the rain. Either way, it’s no different than the back of your exposed alternator which holds the factory bridge rectifier. mine is getting mounted next to the battery on the firewall. I may make a little shield for the vent ports with a 3D printer I have at work, but only because it’s right under the rain tray. Either way I’m not concerned. It’s way more enclosed then the alternator is.
537804
 

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T
the big ol cooling fan on the side may allow for a little water intrusion.. I'm guessing this would be mounted in cab?
the fan is actually not that big and is mounted on the bottom. Either way a little water won’t hurt it.
 
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Discussion Starter #18
Soooooo my alternator went out again yesterday night...so that puts me at about 7 months when my first one went to crap ...battery was not holding charge....I have a napa 130amp and im probably going to have the warranty replace it....anything else it might be or might want to check out when having the alternator out? Also, i have Harley# 356 super stock wiring put on it when my first alternator went to sh!*
 

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Carbon Fiber Addict
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You're probably putting a huge strain on the 130amp with all of those E-Fans. I would swap with a 200amp or remove the H/E Fans.
 

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Discussion Starter #20
Does anybody know the napa 200amp alternator part number i tried looking for it online but can't find it
 
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