I submitted an article to GoRobotics.net - it covers the Firmware update process as well as the brick control window (where you can see battery strength, change the brick default name, view programs and other files, etc.). Check it out here.
I have found when battery strength gets down to around 7 I start getting "strange behavior".
Can you elaborate?
A couple of examples:
1. I bot I designed was supposed to roll at 20% power until the sound sensor triggers (loud - shout) then cut to 5%. When battery was low, the sound sensor would trigger but the motors would start-stop-start-stop-start-stop... not run continually. Replaced the batteries and it worked fine.
2. Another time I couldn't get the UltraSonic sensor to detect my hand movement at the correct distance - I had to practically cover the US sensor with my hand... replaced batteries and problem went away.
"Strange behavior" definition: When I KNOW the bot should do one thing, I've triple checked the program, and the bot continues to misbehave.
Time to start hunting for deals on Duracell...
1. I tend to turn off my brick when I'm troubleshooting.
2. When testing, I (habitually) turn all motors down to low power (20% or less) until I'm happy with the program. This probably adds a LOT to the life of the batteries.