Prentke Romich Company
http://www.prentrom.com/support/article/1670
Check your battery status in the Status Display Area
The Battery Status bar graph in the Status Display Area on your screen gives you the following information:
Full Battery: mostly green lines, a few red, a few yellow
Plug in Charger: no green lines at all
Nearly Dead: red lines only (plug in charger now); you will also see only red lines if the Battery Door is off the unit. The Battery Door must be on the unit or the replaceable battery will not work.
Charger Plugged in: you will have blue lines on bhe bar graph.
The Battery Menu
Go to the Toolbox and select the MAINTENANCE MENU 
Select the Battery Menu option. 
You can activate the Next Battery or Previous Battery option to make sure you are seeing the latest battery information.
Low Battery Warning
When the batteries in your device get low, you will hear a Low Battery Warning. This is a two-toned running beep. When the Low Battery warning sounds, you can no longer do any storing. The warning will continue to sound at intervals until the batteries are dead. When the batteries are dead, the device powers down completely and you cannot use it.
Battery LEDs
There are two LEDs on the top / front of the case.
The LED on the left will blink when the battery charger is plugged in.
The LED in the right will blink when the batteries are low and need to be charged.
When the batteries are low, the Low Battery LED will blink. When you hear the Low Battery warning and/or see the blinking Low Battery LED, plug in the battery charger. The Battery Charging LED will begin to blink to indicate the charger is plugged in.
IMPORTANT! Forcing the charger tip in too far will damage your device!
A complete charge, from dead battery to fully-charged battery, will take 9-10 hours. Your charging light / lighting bolt icon will also go to a slow blinking trickle charge when the battery is full.