Well electrical is definitely not my strong suit. That being said, ah quick way I know how to tell if ah car is charging is to pull the positive battery cable off  (WITH THE CAR RUNNING). If the car shuts off then it's not charging and running off the battery, If it continues to run then of course it's charging. Thats were my electrical knowlege ends.

Last edited by Derek (3/21/2014 6:47 PM)

the old alternator needed a resister to get the charging started on my 65 with ALT light the bulb served that purpose you might have a resistor that back and not letting the alternator to start charging

Have you had the friendly folks at O'Reilly's load test the old battery? 

Or maybe you jiggled those regulator wires "just so" and THAT got it working again ?  Regulator plugs are notorious for the wires getting real brittle where they enter the connector.

Steve;
Thanks for the response. I'm thinking that maybe it really was the regulator. I had already run continuity checks on all the wires and removed/inspected the wires and connectors from the plug before changing the reg out. The harness was replaced about 5000 miles back. I guess I HOPE it was the regualtor. Don't want to play this game again anytime soon.
66gt

Ive installed a 3G alternator in my 66 ACode. Im running without the prescribed MEGAFUSE. It works perfectly. Now the wiring and alternator were robbed off a Windstar. Don't the wires incorporate fusible links making Megafuse redundant? Also my Stock '66 F-250 is ready for an Alternator upgrade. I have a brand new 2g and good clean harness. With no heavy loads to be put on the charging system there shouldnt be a melted wire issue that came with the 2g system on the 80's trucks, right?

BobE wrote:

You need to be careful putting high output alternators in vintage vehicles w/o proper fuse/circhuit breaker protection.  It is not necessarly the system current load, but if you get a short circuit and the alternator will keep feeding the short that could result in melted wiring, damaged components and possible fire.
Modern cars have a much more protected system for that very reason.

 
Should I use the Megafuse 175amp Fuse?

Agree w/ wsinsle, 40-50 amp fuse should be adequate .. unless you've installed many new high power electrical components.  The issue isn't not to exceed the output of the alternator, but rather not to exceed the current carrying capability of the circuit you are protecting.
Modern vehicles have a 'power' distribution block that feeds a "circuit" distribution block in the same vein as a house has a main circuit breaker, and individual branch circuits.