Bad Alternator, Really?!

Everything on the body is referenced to ground, including the battery negative. The spike in voltage you will see if the alternator is disconnected can cause some severe spike in the DC output due to this ground reference being interrupted.

Yeah it's not worth the risk. Old cars with carburetors and points didn't have much to care about as far as electronics. I wouldn't recommend it but if you do, let us know lol

 

https://www.familyhandyman.com/automotive/how-to-test-an-alternator/view-all/

scroll down to just under the picture of the Alternator. I might take ur advice

 

These vehicles will run fine without the battery hooked up, but extended periods is not a good thing obviously.

99% of the time if a alternator is bad the battery light will be on your dash.

 

Started to run into this issue again. Think I let the truck sit too long again.

 

Don't disconnect the battery when running as has been said- this was ok on old cars with generators but is a terrible idea with alternators; it can create a huge spike in voltage that will fry diodes and other very expensive electronic items.

OP, what is sitting too long? I've left vehicles (with no alarm) for 3-4 weeks and no issues on starting.

 

Approx 2-3 weeks

 

My take is your alt is fine and the battery is also most likely fine. When you cleaned the terminals you used a wire brush and cleaned both the battery terminal and the cable clamp. Yes? If it continues read up on "parasitic battery drain," have not had to chased it on a Taco yet myself (knock on wood). Be aware it can be very simple or a PIA depending on the vehicle.

And if any of you are reading 12Vdc on your 66 Beetle - you have big problems or know more than the average squirrel.