The alternator is in....the questions begin

OK so can someone sum up what we have just learned about doing a 3 wire alternator upgrade into a bulleted list of "here's all the steps"?

When I first posed this question away back when in reply to another thread, I showed the initial answers to a buddy of mine and asked "Is this easy to do?" to which he replied "Like brushing your teeth."

While I still agree it is not rocket science it is a bit more like brushing flossing rinsing and using those tapey whitener things.....

So to get it all in one useful package for the benefit of this group...anyone dare to try? Hell I should try...

"Shin bone connected to the knee bone, knee bone connected to the leg bone...leg bone connected to the hip bone..and its just a box of rain..."

 

Sorry, I couldn't come up with a snappy tune to go with this. There are actually a number of options involved, but since it's a 3-wire alternator we can boil it down to three steps:

1. Run a wire from the BAT terminal on the alternator to the battery. This is the "charge" wire.
   • This should be a heavy wire, at least 10Ga, preferably 6-8Ga. Heavier is better but don't be silly.
   • The most common place to connect this is the battery terminal on the starter "solenoid".
   • For safety, this wire should be fused at the end electrically nearest the battery. A fusible link is usually used, but other fusing options are available.
2. Run a wire from the #1 terminal on the alternator to a switched, current-limited 12-volt source. This is the "excite" wire.
   • This can be a lighter-gauge wire, like 16-18Ga.
   • Normally, this is connected to the charge indicator lamp in the instrument cluster. The other side of the charge indicator lamp goes to the "IGN" terminal on the ignition switch, or equivalent
   • If you don't have (and don't want) a charge indicator lamp, you may want to add a resistor or resistor wire. Something like 10-30 ohms should be OK.
   • If you have electronic ignition, or in some cases even with points-type ignition, the engine might continue running after you turn off the key. This is because the alternator can "backfeed" into the ignition system through terminal #1. If this happens, add a diode in series with this wire. Get a 3-amp diode, and install it with the banded end toward the alternator.
3. Run a wire from the #2 terminal on the alternator to the battery. This is the "sense" wire.
   • This can be a lighter-gauge wire, like 16-18Ga.
   • In most cases, you can just connect this to the BAT terminal on the alternator. If you see too much voltage drop at the battery, you can run this wire to the battery (or equivalent) instead.
4. Optional, but a very good idea: Run a heavy wire (same size as the charge wire in step 1) from the alternator's grounding connection (a threaded boss in the back of the alternator) to a grounding point on the engine block.

OK, so that's four steps, but it's not really a 3-wire alternator . . .

Oh, and don't forget to rinse and spit.

 

Awesome.

 

I feel smarter already. Thanks!