Well i just had to share this with someone!!! I went to the parts yard yesterday looking for an alternator for my G3 swap as I still have the origional G2 alternator on Thumper... I found a refurbished unit (had "refurb" sticker on it) on a 3.8L Taurus (cost me $10). I went to the local parts store for a bench test... Tested out great, but the bearings sounded horrible. Luckily it was late and a guy i knew was working... Evidently it was one of their refurb units so he swapped me for a new 130 amp refurbed unit! $10 for a new/refurbed 130amp alternator with a lifetime warrenty in my name... How awesome is that?!?!?

Anyway the question is what guage wire do I need to run over to the solenoid???

 

That's a steal! Our local pick and pull wanted 75+ core for a used 3g unit. I laughed and walked out.

 

I ran 1/0 on my truck, but that's cause I can actually max out the alternator's output. on my old car I use 4 gauge starter cable, worked just fine.

 

The pick ur parts yard usually charges $25 for any alternator, but I'm a regular... LOL...

I was thinking about using some 10gage... I don't know what my trucks draw is but I was thinking about doing the efan conversion, plus i have trailer breaks and fog lamps. not to mention a trailer with 4 side markers and the 2 tail lights... anyone know or could guess my amp draw with all the above installed and running.

 

the bigger the better...... some people ever add 100 amp or 150 amp fueses

 

10-gauge is way way too small! Factory charge cable is like 6-gauge or 8-gauge on these alternators, and that's in the cars that don't pull trailers and such. On your current draw, look at your fuse box and start adding up - the PCM is around 20 amps IIRC, e-fans are another 20 or so, blower fan in the cab is like 15... Then trailer brakes controller can add some decent load too, if brakes and wiring is good. I'd say forget the load, and size up for the alternator's power output: 2-gauge cable is good for up to 150 amps though a length of about 5ft with a very low voltage drop, 4-gauge cable will also work but as hav24wheel said in this application bigger is better. Do not go smaller than 4-gauge tho, you'd be asking for trouble. If you decided to fuse the circuit, 150-amp or 175-amp is what you should go for, 100 is too low considering the alternator's capabilities.

 

ok good to know... that is what I needed. Also what amp fuse do you think I should run for the trailer break control module??? 20 amp? 30amp???

 

Use atleast 4 gauge for the 130 amp alt. with a 150 amp fuse.

I run 1/0 for my 200 amp. I run my wire directly to the battery.

 

For the trailer brakes it's not a fuse that's needed, but an automatically-resetting circuit breaker, how big depends on your controller - look up the specs on the controller, it will tell you how many amps it's capable of sending to the trailer brakes, you want a breaker a bit higher than that - IIRC 30 amps sounds about right tho.

And yes, I got my alternator feeding directly at the battery too, but I also draw most current directly from the batteries (glowplugs, work and offroad lights, power inverter, camper power supply) - on a mostly stock truck you ca feed into the battery directly as well, but you may want to upgrade the short cable between the battery and the fender-mounted starter relay too, actually that needs to be upgraded anyways IMHO.

 

Where did you get the cool gold battery posts??? Those might come in handy when i rewire...

 

About any parts store should have them, they're the gold-plated terminals often used for big sound systems installation.

 

You can get them on Ebay. Autozone also carries similar but they are more expensive.


Yes autozone has some similar but they cost much more than I paid.

 

That was a deal you got on that. I plan on upgrading to a 130 amp from the stock 90 amp.

 

OK so I got the old one out and the new one ready... Opps! the bolt holes don't match/ line up!!!! well no worries there... Ford was nice enough to put a second mounting location in for me (not sure if they did this on 302-351w...) LOL... Fits perfect!
I only have one question this time around. Are there only 3 wires??? Yellow and green (on left) match the OEM colors. So I spliced into the truck harness and ran the yellow back to the solenoid and the green back to it's origional plug... The black 4 guage on the right is my power. I would have went with a red 2 ga or 1/0 ga but this one was on my shelf and brand new...

Any way do I need to ground the alternator itself??? there was a place on the back of the alternator that is threaded for a bolt... I didn't know if i was supposed to ground there or not...????

Last question... Do i need to swap the front pully wheels???? Not sure what size I needed with a 300 I6 motor...

 

I'd check with a local and reputable electrics shop... We have one in DSM called S&H. They put top quality parts in the alternators and starters that they rebuild. I would almost rather have one from them than the cheap mexico rebuilt one I have. Not to say the mexico rebuilds aren't good... I just don't think the parts they use are as good as the ones S&H uses. Seems like the "life time" parts are always rebuilds with cheap parts, and the better rebuilds only have a 30 day warrenty... Go figure... Anyway S&H was only going to charge me $50 for the 3G if I gave them my 2G. You might be able to get a similar deal at your local shop.