I got more than 5 hours with MM v1.4 and a BT GPS on my N800 when I traveled from NJ to FL. In fact, one time the GPS battery died before the N800 did though I did make a stop and can't recall whether I turned off the GPS device.

keep the screen off and lock the screen and you should be good for many hours assuming your battery is in good condition.

Oh and I would suggest turning off any app that would poll the network. I learned that the hard way.

Another thing - the GPS on the N810 is notoriously unreliable. Even with the latest Diablo OS, it sometimes takes hours to get a fix. If my life depended on it, I would stay far away from the N810 GPS. Once it has acquired a signal, it sticks on to it reasonably well. But I highly doubt the "wake up once an hours for 2 minutes" will work at all...

Martin

When I go hicking, I use my old Magellan Model 330. It runs over 10 hours on two AA batteries.

I've used the N810 with Maemo Mapper's tracking on for a few days in the US. The battery lasted between 8 and 10 hours (no other application running, offline mode activated).

But it seemed that when the GPS signal was lost (which happened quite often in NY when entering buildings or the subway), the search for a GPS signal used more energy than simple tracking. So I tried to disable the GPS when I knew that I would loose the signal for more than 5 minutes.

So I guess that if you're doing some hicking and that the trees don't block the signal too much you could expect 8 hours, maybe more if you use something simpler than maemo mapper.

I admit that comparing to SirfIII n810's GPS doesn't shine in term of TTF but from further observations I can see that It's not that bad. It's much better than my Evermore low-cost BT-GPS. I can usually get a fix under 2-3 minutes. At driving speeds it takes longer but is acceptable (ie 5-7 minutes @110km/h).
I wasn't expecting much after readings ITT but reality isn't so bitter to me.

so according to what I read, the n810 isn't my solution
I'm considering either :

- buy a garmin gps (with proprietary maps... that bothers me)
- buy a data logger bluetooth gps

for the second solution I've some question... is it possible to continue the logging while accessing the gps by bluetooth? for example if I put the gps on, activate the logging. I now want to see where I'm on the n800, if I connect to the gps with bluetooth, will it stop the loging?
thanks
JLM