When I navigating with my MIO P550 with only the battery, it will shut off by itself, and it will stop navigating. How can I keep it running in this situation? As it is named as "DigiWalker", it should work all the time with only using the batter. Any one has this problem and how to solve it? Thank you.

Hi,
 
I think the best you can do is a hard reset http://www.hardreset.eu/mitac_mio_ [...] reset.html
 
or you can find any hard reset http://www.hardreset.eu/index_en.html here
 
Then there is a patch for Mio P550 for battery problem, you need to google for it then install.