Question here for the strong minds on this forum. I've only been out twice this year (I think), and haven't charged my Legend since last fall. Well, last night I put it and the external battery pack on the chargers. Let them go about six hours (both were still charging, but had to go to bed). Anyway, when I connected the external battery pack to the detector, I noticed the charging icon come on and indicate that the detector was charging from the external battery pack. I unplugged the external pack and the icon went off. Is this normal?