new electrical leak

[Josh]

All of a sudden my Catalina has 12.6 volts at the neg. post when the car is off. I disconnected the alternator and the condition is the same. Is there a next best place to start looking for this leak?

[ErikLS2]

How are you connecting the volt meter? An electrical "leak" is measured in milliamps, not volts and to check for it you have to disconnect either battery cable and place one lead of an ammeter on the cable end and the other on the battery terminal with everything in the car turned off.

[Josh]

I have the neg cable off the battery. I have the multimeter with one lead on the neg cable and the other lead on the neg battery post. Key is off and all accessories are off.
My battery has gone dead twice in the last week or so. It was so dead that I had to jump it with another battery to get it to take a charge.

[ErikLS2]

You have the meter connected properly, now just set if for milliamps. It shouldn't be much, on a brand new car with lots of computers it's around 50 milliamps. An older car might be 10. If it happened all of a sudden you probably just have a bad battery.

[Josh]

On Milliamps it reads .016. I get the same reading if I put the leads right on the pos and neg battery terminals. I get the same reading on the terminals of a used battery I have sitting in my garage.

This is a 1967, stock, with a power convertible top.

[ErikLS2]

Putting the leads right on the pos and neg battery terminals won't tell you anything on the milliamp setting.

Assuming you have the leads connected properly and the meter on the right setting and scale (please don't be insulted, I see a lot of professional mechanics struggle with this) then I'd say you just have a bad battery.