If the LabQuest battery has been used heavily or subjected to very high or low temperatures (such as being left in a hot or cold automobile), it may discharge quickly, even after being fully charged. It is possible for this use to permanently diminish the life of the battery.
Calibrating the battery can help you determine if the battery needs to be replaced. For instructions on calibrating the battery, see:
How do I test the battery on the original LabQuest?
Original LabQuest Battery Troubleshooting and FAQs
LabQuest 2 Battery Troubleshooting and FAQs
LabQuest Stream Battery Troubleshooting and FAQ
Optimizing LabQuest battery life
How long will the LabQuest battery pack last?