The battery in the LabQuest 2 can sometimes swell up. There are several possible causes of the swelling, including exposure to high temperatures (such as a hot car), defects in the battery, or natural aging of the battery cell.

The warranty on LabQuest batteries is one year. However, if a battery swells within the first two years, let us know, and we will replace it at no charge.

For batteries more than two years old, replacements are sold as LabQuest® 2, LabQuest Stream™, and Go Direct SpectroVis Plus Battery (LQ2-BAT).
To tell the age of a battery, see:
How to tell the age of a LabQuest battery.

When does swelling become a problem?

While the battery won’t always be perfectly square, it should feel firm and should not interfere with the battery door on the LabQuest closing properly. If the casing is obviously bulged out or the battery feels soft, the battery is unlikely to hold a charge and should be replaced.

If you continue to use it, it may continue to swell and can become a safety hazard. The battery should be taken out of service and recycled. For a list of nearby battery recycling locations see:

To increase the longevity of batteries, see also:
What is the best way to store LabQuest units over summer vacation?