Quote Originally Posted by Magnetron View Post
@ jstluise good find on that problem.
The internal battery is for the volatile memory "do you still have all your wpt & plts "??
I do still have my track log and saved tracks, as well as waypoints that were saved. Plts? I think most of what is stored in volatile memory has to do with the GPS information. It took some time for it to get a GPS fix, but I didn't time it and I'm not sure how long it normally takes. I shut off the unit, without removing the main batteries, and turned it on 10 minutes later and it got a lock fairly quickly, so it looks like the main batteries do keep the volatile memory. I'd have to do some more experimenting to really see what is held in volatile memory but at this point I'm just going to replace the battery and call it good!

A little more info on the battery in case anyone else runs across this thread in the future. The battery I pulled out of my unit has a diameter of 6.8mm and overall thickness of 1.74mm, which is more in line with a ML614 battery rather than a ML621 which has an overall thickness of around 2.65mm. The only difference between the two batteries, besides the thickness, is the capacity. The ML614 has a capacity of 3.4mAh where the ML621 has a capacity of 5.8mAh. Both will work since there is plenty of room inside the case for the extra thickness of the ML621. The ML621 will just last longer when the main batteries are removed/dead.

P80oNnx