Higher Amp Alternator How Much Higher?

In the past I would buy re-man'ed or salvage yard units. I recently for the first time ever rebuilt my own alternator myself. I learned a TON about alternators that I didn't know before. Seeing the different failure modes and the effect it has on the parts was a real eye opener for me.

One of the things that I learned is that it's not always a good idea to run the alternator until it TOTALLY gives up the ghost. As a result I proactively rebuilt a working F150 alternator with 230K miles. It seemed like at 230K miles it was past time and rebuilding on my schedule might save a dangerous break down.

Lessons learned:

• It's quite possible to save some real $$ doing the work yourself.
• It's more work than I would have guessed at first but really does get easier with practice.
• It helps to have a rebuildable core because the rebuilding does take time and if working on your DD the time it takes is a real consideration.
• Running the alternator unit the slip rings totally burns up does make the rebuilding harder.
• There are TONS of different combinations of alternators out there. Different frame designs, frame sizes, stators, regulators and other subtle difference that make it important to learn the differences between a Ford 3G, 4G, and 6G alternator.
• Cleaning and greasing the electrical connectors including the MOUNTING locations can make a big difference. Corrosion is the enemy.
• It helps to follow all of the instructions for the best result. I didn't and had a fail on the first attempt.
• My soldering skills were rusty and needed improvement. It's true. If you don't use, you lose it.

For a "how to" reference I used the information from Rebuilder in a box.

How to rebuild Ford 6G alternator
View: http://www.youtube.com/watch?v=iGIdnOwHZUM

http://alternatorstarterrebuildkits.com/

Mustang GT: http://alternatorstarterrebuildkits.com/ford-mustang-4-6/ Note the 1999-2002 GT can come with a 4G or 6G alternator. I can only give direct experience on rebuilding the 6G version.

I found that the youtube videos to be very well done. Note that the rebuilding process is done using only common hand tools (sometimes in very inventive ways). Bottom line. No special tools required.

On to your question. rebuilderinabox offers a "higher amp" upgraded stators for certain alternators. Which could allow you to get a high amp alternator and save some big $$'s in the process. The other positive is this upgraded alternator does not require any vehicle modifications.

One down side is the end product will still look the same unless you send it out for powder coating or paint it yourself. In my case I tried to clean it with only marginal results.

6G High Amp Rebuild Kit For a Ford Alternator
View: https://www.youtube.com/watch?v=N7pFuDb5eBA


In my case I had an old salvage yard alternator that I didn't take back for the core. This turned out to be the perfect test case to practice on.

An option is to get a core from your local salvage yard. Try car-part.com for a searchable list of salvage yards in your area. Note, if you are planning to rebuild yourself it's not necessary to buy a working core. This is a way to save a few $$'s.

Anyway just food for thought. This isn't for everybody.

Edit: if this were my car and the alternator worked at one point in time and now does not, I would think about a worn out alternator or bad connection and not jump first to actually needing a high amp alternator. Also, if not having enough amps were the only problem THEN the situation would get better with higher motor RPM's. Is this the case?

Allow me to expand on WHY I believe that the wire size NOT the problem in this case. And further WHY a larger amp alternator will not over come the problem IF the wire size is too small.

IF the only thing wrong was the size of the wire, THEN how do you explain how this did work at some point in time? But why guess. Let's test.

Using an accurate Volt-Ohm Meter (VOM), measure the voltage at the battery negative and the alternator case with the motor running and accessories off. Repeat the measurement with all accessories on. This will give a direct reading of the voltage drop caused by current flow. Compare the readings between accessories off and accessories on. The voltage reading should be small.

For completeness sake repeat the measurement between battery positive and the B+ post of the alternator.

Here's even more detail on how to perform a voltage drop test.
https://www.stangnet.com/mustang-fo...perform-charging-system-voltage-drop-test.56/

Note, this test assumes that the alternator is working. It will not produce accurate results if the alternator has flat failed.

If the wire size is so small as to cause a "no charge" condition then the voltage drop would have to be at least as great as the difference between battery voltage and alternator charging voltage. 14-12=2 volts.

Here's why a lager alternator won't fix a problem of under sized wire. The alternator's voltage regulator is located inside the alternator. So the regulator will attempt to maintain 14 volts at the alternator. The wire size is still the same. Therefore the voltage drop to the battery would still be the same even though the capacity of the alternator is higher.

The only way a larger amp alternator is ever going to fix a problem is if there's a difference between alternator voltage (case and B+ terminal) with accessories off and accessories on.

One point that's important to remember is in stock form the stock alternator is large enough. We know this because there are TONS of cars on the road with working alternators and batteries. So in all cases with all accessories OFF, the stock alternator has to be large enough. If the alternator isn't putting out enough amps there has to be a reason why it isn't.