Originally Posted by Gerrye
My batteries seem to be doing about the same as the rest of you, but I do have a spare PE for the eventual demise of one of our regularly used PEs.
That's not going to help in terms of battery lifetime; a lithium ion battery has a finite lifetime, and it will lose capacity whether you use it or not. A 3-year-old battery will probably have lost 30-50% of its initial capacity. The battery will probably be dead in around 5-7 years.