In April and May of 2014, some LabQuest 2s missed the on-board fuel gauge programming step (details below). This can be fixed by updating to 2.3.1 or newer at:

How can I tell if my unit has not been programmed?
Go to System:System Information:Battery
The parameter FullAvailableCapacity should be a number over 3000. If it is under 1000, the unit has not been programmed.

What units are affected?
LabQuest 2 units with serial numbers 14004311 through 14014489. (This is stamped on each unit near the bar code on the back label.)

What happened?
As part of the manufacturing process, the on-board fuel gage is programmed with a profile to match a typical LabQuest 2 battery. A temporary process change caused this step to get skipped. The result is the fuel gage does not work correctly on these units, causing problems such as “not holding a charge”, “won’t charge” or “bad battery”. We have since corrected our manufacturing process to ensure that the problem does not happen again.

See also:
LabQuest 2 Battery Troubleshooting and FAQs