Go Direct sensors have a battery in them for wireless applications. If a Go Direct (GDX) sensor is connected to LabQuest 2 via USB, it will try to charge its own battery from the LabQuest 2 battery. This will cause the LabQuest 2 battery to drain very quickly. This happens particularly fast with some of the more power-hungry Go Direct sensors, such as: Go Direct® SpectroVis® Plus Spectrophotometer, order code GDX-SVISPL, $399, Go Direct® CO2 Gas Sensor, order code GDX-CO2, $199, Go Direct® Optical Dissolved Oxygen Probe, order code GDX-ODO, $298, Go Direct® Motion Detector, order code GDX-MD, $99, and Go Direct® Sensor Cart (Yellow), order code GDX-CART-Y, $169 and Go Direct® Sensor Cart (Green), order code GDX-CART-G, $169.
If you plan to take data with a GDX-SVISPL and LabQuest 2 via USB, you can remove the battery from your GDX-SVISPL and it will function as expected without draining the battery faster than expected. (Now you have an extra battery for your LabQuest 2!)
In general, before collecting data with a Go Direct sensor and LabQuest 2 via USB, make sure both the LabQuest 2 unit and the sensor are fully charged. If you plan to take data for an extended period of time (>2.5 hours), you may want to have an AC power supply for your LabQuest 2 available as back-up.