A couple of battery questions
 

Hi, apologies for my first post starting a thread. I have been a lurker here for a while and love how easy it is to get advice and help.

I did a search but couldn't find anything covering these two issues.

1. I was out for a bike ride along the West Highland Way (Scotland) the other day. I was using eCoach to track my progress (as I have done before) and Open Cycle Map on maep to check we were following the right route. After a particularly rough part of the route I checked my n900 and all was fine. A little while later I checked again and it was off. I didn't think the battery could run out so quickly but I changed to my spare (full) battery and it switched on. About an hour later I checked again and it was off and wouldn't switch back on again. When I got home I plugged it in and it switched on and everything was working as it should.

My question is does anyone know what might have caused the n900 to switch off? I would assume it was just the battery coming loose, but it managed to survive the rough part of the track and it was on the smooth road sections I noticed it.

I have attached the battery graph for the journey, and interestingly it looks like the batery continues to discharge even after the unit is off. I noticed it had switched off at 15:00 and made no attempt to switch it back on until just before this screenshot was taken. (the sudden jump of charge at around 13:00 is me swapping the batteries)

2. My other question is related. I swap batteries quite often as I have an individual battery charger so I always have a fully charged spare. Sometime when I swap batteries the unit resets and I have to re-enter the time and date (like when I first got it) other times it switches on with no need to input these things. Can anyone explain to me why this happens so I can avoid having to enter the time and date every time I swap batteries?

Any help will be very much appreciated, thanks in advance.

sorry for such a long first post