My wife recently bought this battery tester, which allows us to test our red dot batteries under load. Lots of interesting information. Her SRO battery, the original one installed in early July, and used through the summer still shows near 100 percent. One in a Romeo 3 Max, that might have an issue with the motion system, down to 80 percent after three days. Wish I had this during the Acro testing.
A must have Christmas gift for a red dot aficionado!