The long-term life of the battery will vary, but you can expect 400 to 500 full charge/discharge cycles for our LabQuest batteries before the battery will need to be replaced. A charge from halfway to full would count as half of a charge cycle. It is fine to charge the battery every night, even if the battery is only partially discharged. There is never a need to condition the battery by regular full discharge/charge cycles.

The battery takes 10 to 12 hours to completely charge. It is safe to leave the battery charging indefinitely. The time that a battery will last after being fully charged depends on the device it is used in. For example, LabQuest 2 and LabQuest Stream use the same battery, but the LabQuest 2 will drain the battery faster since the battery is powering the screen. The discharge time also depends on the sensors used as some sensors require more power than others. In most cases you can expect batteries to last for a full school day, or 6 to 12 hours, between charges.

When using LabQuest 3, LabQuest 2, or original LabQuest with a computer or Chromebook, the LabQuest cannot operate on USB power alone. It must have a charged battery or be connected to AC power. LabQuest Stream can operate without a battery or power adapter while connected to a computer or Chromebook via USB.

Exposure to temperatures over 35°C (95°F) will significantly reduce battery life. For example, leaving a LabQuest unit in a hot car all day will reduce the battery life. This is the most common reason for premature battery failure.

As a battery reaches the end of its useful life, the run time will become shorter and shorter. Eventually the run time will be too short to be useful, and you will want to replace the battery. When the battery reaches the end of its life, you can calibrate the battery so it will give a more accurate reading of its remaining charge.
See also:
How do I test the battery on the original LabQuest?
How do I test the battery life of the LabQuest 2?

LabQuest batteries are warranted for one year. In typical school use, most batteries will last for about three years. Replacement batteries are available from Vernier:
LabQuest® 3 Battery (LQ3-BAT)
LabQuest® 2, LabQuest Stream™, and Go Direct SpectroVis Plus Battery (LQ2-BAT)
LabQuest Replacement Battery (LQ-BAT)

See also:
Optimizing LabQuest battery life
LabQuest 2 Battery Troubleshooting and FAQs
LabQuest Stream Battery Troubleshooting and FAQ
Original LabQuest Battery Troubleshooting and FAQs