2 years old.
I have 2 Lx3 units with 2 year old batteries as well, all units have been used basically the same # of hours, same conditions, stored the same way and charged at the same time.
The 2 Lx3 units were at 60-70% when I hooked them up last night and were at 100% in less than 30 minutes last night.
buckshot the 5i will have the same charge time as your 3’s the red green light has been a marcum issue for quite some time, a lot of guys have opted for like a battery tend jr option. Good luck!