Three times now my car has not started after sitting for just a day.

New battery in November.

Engine starts up just fine with a jump so it is not a bad starter.

I checked the battery and it held no charge. Drove it around for an hour or so and the battery is fully charged so it is not a bad alternator/charging system.

After driving, the battery voltage reads 12.6 V. With the engine running it reads about 14 V. Looks right there too.

When I pulled a cable and measured for current across the battery post and cable, I get a negligible loss - like 0.3 milliamps. So it doesn't seem like there is a draw on the battery.

But then the car won't start again.

Just a lemon of a battery?