This is a good update on longevity of a battery charge. I've noticed the same with the batteries stored in my heated shop.
As I've posted before, I've had all five of the Lynx tools for about two years. Started with the pole saw, which still cuts nicely through limbs as large as 6". It's almost time to sharpen the chain, and same with the 14" chain saw, both
for the first time! Even though the Oregon chains are micro-chisel for safety and narrow gauge to reduce cutting resistance, I'm pretty impressed with them.
Instead of buying the spare battery, which never goes on sale, what I recommend to folks is to wait for a Lynxx sale coupon, then buy a second tool. With five batteries and chargers, you could literally run all day if necessary.
I gotta say that the pole and 14" chain saws, blower and hedge trimmer are all quite impressive. The string trimmer, not so much. It is the least robust of the five tools. It only takes a thin gauge of cutting string, for obvious reasons (.065", available in bulk at HD, Lowes, etc.) and the "auto-feed" feature doesn't really feed, at least for me. It's not bump-and-go, rather is supposedly actuated by centripetal force. But it's easy to stop every few minutes, press a release button on the spool and pull out more string. The thing is really handy for quick, light trimming when you just don't want to fool with fuel mix and the gas trimmer. I grudgingly admit it's grown on me.