Upgraded Alternator?

displacedtexan

Active member
Add up the load.... do you NEED more???? Altho a Cummins in a Ford sounds non stock.... electrical load is the same on anything, even a house.
Many of the loads you list are part time, even rarely used. Maybe you need a bigger battery but the factory alternator is likely fine.

Big alternators are needed on ambulances which might run ALL systems together on an accident scene for hours, medical equipment, comms, flashers, scene lighting, AC/HEAT, bit most of us overlanders rarely if ever need it all.

Will you ever be airing up tires and winching while the wife cooks dinner in the microwave and the kids are playing video games?
Aftermarket stuff, besides the swap-
Radiator fans are 40a
Fuel pump is 20a
Trans cooler fans are 20a
Stereo amp is 60a
Plus a few other small drains.

Those are all being used any time the engine is running. Already have two group 65 batteries.

That's assuming I'm not running the winch, inverter, lights, or air compressor.
 
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displacedtexan

Active member
In the same boat. Going Mechman hairpin Elite series 350amp. Probably won't use more than 210 amps at a time. But. What the hey you only live once. I'll be powering all the stuff you mention and charging a 400ah lithium bank in my camper when camping through a B2B DC-DC converter.. Gonna do the "big four" cable upgrade, don't forget that part. Higher amp demands demand a 2nd look at the factory cables

But, forget the alternator. LET'S SEE SOME PICS OF THAT FUMMINS!!
Wound up with a Mean Green 220a, I'd already upgraded cables.

Took this pic waiting for the new battery terminals. 20220413_083554.jpg

It's nothing too special.
 

billiebob

Well-known member
The biggest advantage to a good larger alternator is the amperage to can get at idle.
Not true, I ran tow trucks, we had massive charging, boosting systems, plus an Idle up switch to up the amperage when parked.
At idle, the double alternators could not keep up with the demands of an accident scene.
Popular idea but not true..... you have a big amp draw.... you must idle up.
 

displacedtexan

Active member
Not true, I ran tow trucks, we had massive charging, boosting systems, plus an Idle up switch to up the amperage when parked.
At idle, the double alternators could not keep up with the demands of an accident scene.
Popular idea but not true..... you have a big amp draw.... you must idle up.
But if the alternator puts out more power at idle... You don't.

My factory alternator was 110a max, running the ac at a stoplight I have more draw than that in aftermarket stuff.

But my new alternator puts out 140a at idle.
 

FordGuy1

Adventurer
Not true, I ran tow trucks, we had massive charging, boosting systems, plus an Idle up switch to up the amperage when parked.
At idle, the double alternators could not keep up with the demands of an accident scene.
Popular idea but not true..... you have a big amp draw.... you must idle up.

Really that is not the case. Stock Alt at idle may put out 30 amps, when hot even less. A quality Alt like a DC 280amp will put out 85-100 at idle. That is a huge advantage, also many stock alternators will have a voltage drop to low 13 volts when hot vs. 14.2 with a upgraded unit. This is especially helpful when you are charging remote batteries.
 

DirtWhiskey

Western Dirt Rat
Wound up with a Mean Green 220a, I'd already upgraded cables.

Took this pic waiting for the new battery terminals.

It's nothing too special.

Oh yeah, that's special! Sort of trippy looking at all that SPACE under the hood with the straight 6! Always loved Fummins trucks. Did you do the conversion?
 

displacedtexan

Active member
Oh yeah, that's special! Sort of trippy looking at all that SPACE under the hood with the straight 6! Always loved Fummins trucks. Did you do the conversion?
Thanks! And yeah, it's almost crazy how much room there is under the hood!

I did do the swap. Bought a short block that needed torn down. Rebuilt it, it's also got a cam and p-pump swap. Sitting at 500ish horsepower.

Got an adapter plate and custom flex plate to run the 5r and modified the harness. Slid the engine back about 2.5"
 

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