I went went out for a ride last week. I hadn't used the device in a few months but battery was indicating 100% so I didn't charge it.
I followed a preloaded course for the ride which took 2 hours 20 mins. In that time the battery meter reading had dropped to 45%.
I then charged it up and left it running on my desk (Not following a course but just recording while stationary). Now I got 6 hours until the meter dropped to 0% and another 6 hours before the unit switched off. (Total 12 hours)
I charged it up and repeated the experiment again. Next time it ran for 8 hours 45 before showing 0% but expired after only another 30 mins. (Total 9 hours 15mins).
I'm using latest firmware (5.30) and I didn't use battery saver in any of the above tests. Screen brightness was set at 30%.
What's the best way to calibrate the battery meter? I thought it might be to fully discharge as I have been doing which does seem to sort of work, but I don't like that the battery life had dropped from 12 hours to 9:15. Should I be leaving it on the charger for a while after it shows 100%?