Hello,

all the time when my battery is gone or i change it to another one and start up the device i'll be asked for the current date and time.

What i want to do automatically on startup:
Set the clock time from 12hr to 24hr a day
Get the time from Provider (my support it actually)

Is there any way to do that? Any ideas? Or is there even a setting to prevent that?

i use that sync-time-widget that sits in the menu dropdown press it whilst online and it updates your time and date.

swap batteries faster. N900 holds date and time for a short time without a battery and if you put another battery in this time you will save time

Well actually it's not a BIG problem anyway, u can just click ok on the homescreen and then go to settings -> date time and check both checkboxes. Unfortuantly it sucks. I don't need to run ntpdate on a cronjob (which will not help me though with the am/pm to 24 hours function though).

I swap batteries kinda fast (maybe in 3-5 seconds), with no effect.

automatic update of time
and it will switch ur clock to 24 hour so u can change that in settings..
but if u change that from the startup screen, it will cancel the auto update..

isn't there a command which i can call regulary on my n900 which will set these 2 settings for me in a cronjob that i'd not need be be worried any more?

The reason why your phone always ask for time & date after empty battery or you swap your battery is because you need to replace a small battery inside your phone....
now this small battery (smaller than a watch battery) is use to keep the time & date running all the time (when you turn off your phone)...
how to change it???
well the only way to replace the small battery is to go to nokia center @ any handphone repair shop...