My LabQuest was subjected to extreme temperatures and now it discharges quickly.

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:
     TIL 2075: How do I test the battery on the original LabQuest?

See also:
     TIL 2077: Original LabQuest Battery Troubleshooting and FAQs
     TIL 2741: LabQuest 2 Battery Troubleshooting and FAQs
     TIL 1780: Optimizing LabQuest battery life
     TIL 1768: How long will the LabQuest battery pack last?