Ultimate Battery Thread, Main, second, isolator, and winch/battery problems.

[Bradley Thornton]

Thought I would talk about one more subject the Alternator.

• 2.3L EcoBoost (210A rating): Delivers ~130 amps at minimum idle (750 rpm).

• 2.7L EcoBoost (210A rating): Delivers ~85 amps at minimum idle (580 rpm).
• @2300-2500 its at max 210 amps

240amp stock alternator

• Low Idle Output: ~110 amps at minimum idle (~625 RPM).

• Maximum Output: 250 amps achieved at or above 2,500 RPM.

How do you know if you need to upgrade.
Healthy battery, truck off is 12.6-12.8
Truck on it should read 13.5-14.7 If its under 13.5 your Alternator is bad or not keeping up with amp load at idle.
If it's below 13.5 test the amps, easy way is to use a Klein CL800 or something like it.
At idle clamp it around the positive cable, say it reads 50amps and volts are 13.2 now run the Truck up to say 2000rpms read amps say its 80amps and reading 13.6 you now know your Truck needs 80amps at idle to work properly.

Now options
If you can get the specs on your alternator you may can buy a smaller alternator pulley or have one made if you won't exceed the max RPMs of the alternator
Calculation you need to know
Crank is 4.75 Alternator pulley 2.75 now RPM, 4.75 divided by 2.75 = 1.73 x 900rpms = 1,554 alternator RPMs
Max on alternator is normally 15-18k Max rpms on the Bronco is 6200rpms (rev limiter)

upgrade to the 240amp if 110amps meet your needs

Upgrade to a aftermarket alternator (Only one brand I trust at this level Mechman alternators)
Call them and they can make sure you get what you need.

When upgrading an Alternator good chance you will need bigger wire also.

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[Bradley Thornton]

That dude on youtube that tests all kinds of tools, batteries, ect just did a really good video on batteries. Tested Walmart against O-Reilly batteries, was pretty interesting, and a lot of good info. Ill add the link when I have more time...or if someone finds it

Guessing this one I like this guy.