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Upgrade to 130A alternator or no?


97Ranger3.0

Well-Known Member
Joined
Nov 22, 2017
Messages
177
City
Florida
Vehicle Year
1997
Engine
3.0 V6
Transmission
Manual
Total Lift
4"
Tire Size
33x12.5
Hey guys, looking for an opinion on what to do.

I've got a 1997 Ford Ranger with the 3.0 which has a 95 amp alternator from the factory. The alternator was already replaced when I bought the truck and seems to do fine. However, I've added a two speed electric fan from a 3.8 Ford Thunderbird being run with a VW temp switch and a Volvo relay as many people do. It works well and I've never had the fan kick on anything but the low speed. My air conditioning does not work currently, but I am planning on fixing it soon. So this is where my dilemma is - when I fix the AC, I plan on wiring the electric fan to run on the high speed setting at all times with the AC being on (other than if I use a manual over ride switch to shut it off if I'm cruising at highway speeds).

So what I'm wondering is, would I be pushing the limits of the 95 amp alternator if I had all of that running at the same time? If so, should I swap to a 130 amp alternator or is there anything else I can do with the 95 amp? Also, if I do need to swap to a 130 amp alternator, do I need to upgrade any of the alternator or battery wiring?

Thank you
 
That does sound like a good idea
Your current 95amp alternator only has 50amps at idle, its 95amp rating is at about 1,800rpms on the engine
A 130amp alternator would have 65-70amps at idle

ALL alternators are rated this way, max amp rating is when engine is at about 1,800rpms, you get about 50-60% of that rating with engine at 700-800rpm

On a 1997 you should add another wire from the B+ post on the back of alternator to the Power distribution post on the inner fender, and this wire should also use a Fusible link, 12 gauge, Ford's is a dark grey fusible link

Follow the positive battery cable to the Power distribution post(starter relay), thats where the current B+ wire is connected
You can usually see its fusible link connected there, you are just duplicating this connection for higher amp
Use same gauge wire as seen on B+ now, which should be 8-10gauge, and same type of fusible link at power post, 12gauge

Or you could change to ONE 6gauge wire and a Mega-Fuse, 175amp, Ford did this setup in later years

You could get all this at a wrecking yard, wire, fusible links or mega-fuse, used on most Ford trucks

The other 3 wires on alternator are fine, they are lower amp for voltage regulator
 
Last edited:
That does sound like a good idea
Your current 95amp alternator only has 50amps at idle, its 95amp rating is at about 1,800rpms on the engine
A 130amp alternator would have 65-70amps at idle

ALL alternators are rated this way, max amp rating is when engine is at about 1,800rpms, you get about 50-60% of that rating with engine at 700-800rpm

On a 1997 you should add another wire from the B+ post on the back of alternator to the Power distribution post on the inner fender, and this wire should also use a Fusible link, 12 gauge, Ford's is a dark grey fusible link

Follow the positive battery cable to the Power distribution post(starter relay), thats where the current B+ wire is connected
You can usually see its fusible link connected there, you are just duplicating this connection for higher amp
Use same gauge wire as seen on B+ now, which should be 8-10gauge, and same type of fusible link at power post, 12gauge

Or you could change to ONE 6gauge wire and a Mega-Fuse, 175amp, Ford did this setup in later years

You could get all this at a wrecking yard, wire, fusible links or mega-fuse, used on most Ford trucks

The other 3 wires on alternator are fine, they are lower amp for voltage regulator

Thank you very much for the advice! I will add all this to my list to do when fixing the AC.
 

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