Typical car battery, 12V. While connected to the car, It read 12.38V on my multimeter. Using the absolutely same multimeter, I measured it once I disconnected it from the car - voltage went to 12.56V. This is in the span of 5 minutes. First measure was taken outside at 1C, second at home at 18C.
Car sat for 1 week straight before disconnecting it. I charged it and reconnected, after sitting for one day voltage was back to 12.4V, thus I eliminate some sort of crazy parasitic draw as else after 1 week it would be dead, not same as after one day.
Is that type of drop to be considered normal?