72 GTO - Charging issues - part 1

Today we are working on a friend's 72 GTO drag car. It has been having a problem with the battery going dead after just a few runs down the drag strip. At first, I assumed it was because the large alternator pulley wasn't spinning the alternator fast enough but after some testing, we found the real issue...
Check out part 2 here: • 72 GTO - Charging issu...

[@SnowFamilyRacing]

A possible reason for the voltage difference of 1 -ish volt between the alternator and the battery could be due to an undersized charging wire. I'm running a 4 ga wire on my El Camino and I'll have to run this test to see what it charges at and what's at the battery. The wire realistically need to be able to handle enough amperage to charge and support the power requirements of the car. Also, a smaller gage wire can work if the battery is closer to the alternator. On our race cars, it's hard to get them further apart! I'm a fan of running stuff too big, my main power and ground is 1/0 ga braided welding cable rated at way more amperage than my car could possibly support.

[@BruceCoggins]

We are planning on doing a part 2 and we will be changing the charge back wire and continuing with the pulley test. We'll be checking volts and amps. Going from 10ga wire to 8ga wire.

[@jmalone2758]

Start pulling fuses, narrow it down.