Battery Life? TIP

I'm changing out a 9V battery in my guitar preamp.
While the owners manual says you can get 100 hours of performance, it never seems to last that long.
To keep track of the new battery life, I marked the install date: 6/11/2014 with a Sharpie



This might be an interesting test for launch controller batteries, especially the Quest controller that also uses a 9V battery. The single 9V battery seems to lose its ignition strength faster than the Estes 6V controller.
You could also mark one of the four AA batteries in an Estes style controller.
If you keep a flight log (recommended, go to www.rocketreviews.com, register and start a flight log) you could keep track of how many launches and in turn, how many batteries you use.