Solid advice.

I've been charging it at night in my place and reinstalling the battery every morning. Gets me to work and back. I'll get it to the shop Monday and test it, then order the part. At least it still runs. Its really weird how the ammeter goes nuts when my RPMS get high. I took a video, but haven't had a chance to upload it.

could be over charging.

Wouldn't that be more likely to cause battery and accessory failure than a dead battery though?

The 280zxt i had, went to work, at lunch it was completely dead. I charged the battery and took it in to check. Idling it showed good, until I revved it high, then it showed 17+ volts. While taking it over to the shop, all the dash lights went haywire.

Check it before it does damage to the battery. I had an optima so it didn't do much harm to it.

Dead voltage regulator or alternator...

FSM has test procedures, BTW.

Details of Alternator upgrade & elimination of voltage regulator. Please note for the '73 you'll need a different jumper setup so that the fuel pump relay isn't always powered up.

Dave's 1972 Datsun 240z: Alternator Upgrade

Thanks guys. It runs well enough to get it to the shop tomorrow, I'll give it all a try.

Just wanted to close this up. I tested the systems and determined it was the alternator. I was able to find an Ultima brand alternator locally, and put it in the same day. It did not fit initially.. I had to shave of a bit of metal to get it mounted. Just a warning to anyone purchasing that brand.

I spent a little extra to get it local, but overall the cost of the repair was under $40.

Other than the size issue, it went smooth and was a nice reminder of how easy these cars are to work on...

For the time being, I am staying on an externally regulated system. With the new alternator, the electronics run better than they ever have since I bought it a year ago.. and the engine is actually louder! Makes me wonder if the weak alternator was actually shortchanging my ignition system.

Either way, its running good again. Thanks for the help.