Jimbo,
I use mine to control my fermentation chamber using Craftbeerpi. The first time I used it i set the update interval to 1 minute to keep the chamber at temp. The battery lasted for 13 days which was one day short of me racking the beer.
After that i made a modification and removed the LED from the gyroscope (which was on all the time). My next batch I changed the update interval to 1.5 min and it lasted the whole 14 day fermentation and judging from the battery usage it could have gone for another week or so.
Most people set the update interval to 15-20 min so they report battery life that would last months.
Yes, the unit can change from F to C in the setup menu.
The unit is as accurate as the calibration. Some people use a water/sugar mixture to calibrate doing a 5 or 6 point calibration. I use a 2 point calibration using my OG and water. So far my FG is ~2 points from my hydrometer reading. From what i have read it's because i am fermenting under pressure and the Tilt devices show the same difference. I don't mind the slight difference as I use the spindel to let me know when fermentation is complete based on movement.
