I finally got to try this thing out after having it for two months.Hiked four miles into a lake using my new PN-40se gps, spent the night and the next morning I plugged the gps in to charge it, everything looked to be going well so I let it charge for about 15 minutes and re-checked it only to find the screen blank (as it was on when I started) so I unplugged and tried to turn it on, and nothing. Very unhappy!.When I got back to the truck I found the gps still worked if I put regular battery's in it, so it ruined my brand new rechargeable batts.Be warned (check it out before you go!)