I finally had to replace the CR2032 battery in my Backwoods Logger Classic yesterday. The nominal 3.0V voltage had fallen to about 2.7V, and while the software appeared to be functioning, the LCD display no longer worked reliably. The battery was new in June 2011 when I built the first Logger prototype, so that’s two years of battery life while doing continuous logging the whole time! In a post back then, I measured the average current draw at around 20 uA and estimated a battery life of “more than a year”, which proved to be pretty accurate.

The Logger Mini is more of a battery hog due to its OLED display – its AAA battery will last for several months of continuous logging. So the Classic is still king when it comes to long-term data collection.