Battery Voltage Loss With Key Out

I got the battery mostly charged at 12.6v and it held there for 3days sitting out of the car.
I bought a new 12v test light, and I switched my test leads on my meter to the correct position.

My battery has two top posts and two side posts.
I started out with the alternator wire hooked up to the side post on the battery and used the test light between the neg post and the neg cable. No light and it tested at .02ma dc.
Then I hooked up the body 12v cable to the top post and got the same results, no light and .02ma dc.
Then I opened up the drivers side door and had a bright test light and had a reading of 17.0.
I then shut the door and turned on the parking lights and got a bright light and a reading of 40.0.
Then turned on the main head lights (wired to relays) and got 88-89.0 and the headlights came on.
I retested the battery and its still at 12.6 v and I am leaving the cables hooked up to it and I will check the voltage tomorrow night.

So the test light was not lit with both positive cables hooked to the battery and a reading of .02-.03ma dc.
I cracked open my drivers door a little as I could and I was getting the test light to come on. So I am wondering if I left the drivers side door opened that Thursday night (I was in and out of the drivers seat a few times while it was running) and I covered up the car and did not realize that I left the door cracked.

So I will check the battery again tomorrow night and see what the reading is. If it is good then I’ll start it up and see what the alternator is charging too.

Thanks everyone!