My car had the distinction of being loaned to the National Automobile Museum for a Muscle Car display. The display was a three month stint. I had zero issues with the electrical system when it was placed for the display. The battery was disconnected and the engine not run for the display.. When I picked up the car it required being jumped to start but then ran well. Then put the car into the shop to fully charge the battery and see what was happening. While in the shop the battery would intermittently go dead and require recharging, The shop owner who is superb is mystified as to the draw and surmises that when the battery was reconnected it possibly spiked something to initiate the draw that will discharge the battery. The battery is new (within three months of it being disconnected). Tomorrow the search begins to find the issue but I thought maybe one of the gurus here would have a similar experience and offer a suggestion or two. Could it be something so simple as a bad battery? It’s one of those issues that make you go “Hmmm”.
70 442 455 convertible.

 

Yes it could be a bad battery, can you try another one known to be good? Is there a current draw when the car sits, how much draw? Does it have any aftermarket electrical equipment? Look for trunk, glove box or underwood lights being illuminated when they should be off.
Good luck!!!

 

It's probably a bad battery. However it could also be the voltage regulator or bad diode in alternator. Put a test light in line with the pos or negative battery cable to the battery post and see if the bulb lights. If it does you have a draw.

 

Also, if the test light shows there is a current drain, unplug the alternator to see if it goes away. If so, bad diode as said above.

 

Gentlemen
Thank you for your suggestions. This site continues to impress.