This past weekend I switched my everyday key with my spare which hasnt been used in about 6 months. The spare would not unlock the doors (remotely). The little red light blinked the same as it does on my good key, but the car didnt respond. I then unlocked the doors with my good key and started the car with my spare. I drove for 20 minutes and then got out of the car. My spare key works fine now.

Does the battery charge or the key program itself while its in the ignition?