I kept it in sleep mode.
ALL belts were still, and in the supplied box, the black one with the charger, and it retained 30% of charge up to 2 weeks.
Then 3 weeks, it was close to 10%.
I began to charge it....because when I tried to reach say 0% with my Sony VAOI, it may take 1 day to regain enough juice to even start!
I dare not try it with the Devon...yet..