Just wondering how long the battery will last without use. My van has sat on the drive for just over three weeks over Christmas and the app was showing 12.57 volts on the battery so thought I would take her for a run, did 25 miles and back up to 12.9v, I have one of those solar battery conditioners but haven`t used it as yet but might put it on just to be safe. How long have you left yours?