Mechman high-output alternator


My truck has an auxiliary battery that I've added. All of the electrical accessories I've added run off this auxiliary battery. Some of these accessories, such as the two-way radio and cellular phone, are on all the time. This constantly drains the auxiliary battery. The stock alternator cannot keep both batteries fully charged. My auxiliary battery usually lasts 6-12 months before it is completely dead. Also, when I'm parked at a motor vehicle accident with my emergency lights on the auxiliary battery will slowly discharge since the factory alternator can't supply enough amperage at idle.

My factory alternator puts out around 13.6 volts normally. If I charge the auxiliary battery the factory alternator will put out around 14 volts...until the auxiliary battery starts to discharge.

In an attempt to keep my auxiliary battery alive, and for better overall electrical performance, I've decided to replace the factory alternator with a high-output aftermarket alternator. I'll store the factory alternator. If I buy another Ford truck someday I'll move the high-output alternator to it.

Something else to consider...the factory alternator is rated at 130 amps (cold). In the real world, when the alternator is hot, it is probably lucky to put out 100 amps. The 175 amp high-output alternator I'm using is rated at operating temperatures (hot). The cold rating is around 200 amps. Click here to go to the Mechman website.

Here is the Mechman Propower 175-amp alternator.

Here is the $2 bracket that they charge $29.95 for...I wasn't too thrilled about that. I could have fabricated a bracket like this in about 20 minutes.

Here are some comparison pictures of the aftermarket (left) and factory alternators:

One difference I noticed is the ProPower alternator has a slightly smaller pulley. This will cause it to spin faster at a given rpm than the factory alternator.

I was a little worried when I saw the factory alternator was larger than the aftermarket one. I assumed the aftermarket alternator would be bigger. I took a "wait and see" attitude at this point.

The factory alternator has an external regulator. That is the gray plastic thing on the back of it. The Mechman alternator is internally regulated.

Click here to see the alternator installation.

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