1977 K30 draining battery

[Grit dog]

One would ASSume that the OP would notice if there were other wires still hooked to the battery when they disconnected the battery cable.

I bought a car two months ago. It had a battery drain issue, when purchased. I know the PO, he put a new battery in the car in November. I fully charged the battery with it out of the car. It load tested fine. Then the next day, it load tested very poorly.

Same thing not too long before that. I bought those ambulances in July or August. I bought a new battery for one to get it home, and wound up using that one to drive everyday. After a few months it started going dead in a few days. Then overnight. Then in a few hours. After removing the battery and properly charging it, it spectacularly failed a load test.

Most likely a coincidence, but both of those batteries were purchased from O'Reillys. And they were both the "gold" or whatever the better ones are. Not the super cheap ones.

Fair enough. I’ve had several of those “bad” new batteries. They all had a red lid and called Optima. (Junk)
That said, given the OPs obvious lack of knowledge and lack of replying with additional info, figured good chance that maybe it isn’t truly disconnected.
Examples, my 77 has camper wiring hooked up on battery #2. Battery 1 disconnect kills the whole truck except the camper wiring.
Same with the 86. It had a disconnect on the - terminal which I’ve left in place. But after adding stereo amp wiring, the amps are not hooked thru the disconnect.

 

[Sad Sack]

The OP has left the building…