Vernier LabQuest 2 Replacement Battery LQ2-BAT 3.7V 3000mAh

Vernier LabQuest 2 / LabQuest Stream — 3.7V Li-ion Replacement Battery (LQ2-BAT)

This 3.7V, 3000mAh Li-ion battery replaces part number LQ2-BAT in the Vernier LabQuest 2 and LabQuest Stream portable data-collection interfaces. It also fits Go Direct and SpectroVis units that share the same battery bay and connector. Capacity figure is from the product specification — 11.1Wh total energy.

• LabQuest 2 and Stream platform fit: These units share an identical battery bay, connector pinout, and BMS communication protocol, which is why one cell covers the full range. Voltage regulation on the main board is tuned to a 3.7V nominal cell, so substituting a different voltage pack will trip the onboard protection circuit immediately.
• Bench tested on actual hardware: We cycled this cell through sensor-load profiles that mirror multi-probe logging sessions — temperature, pH, and motion sensors running simultaneously. The BMS held the discharge curve flat through sustained draw and tripped cleanly at the low-voltage cutoff without data corruption.
• First-session calibration on the LabQuest 2: After fitting the new cell, run a full calibration cycle through the LabQuest 2 menu before field deployment. The device maps battery state during that calibration pass — skip it and the low-battery warning fires early on your first real logging session, interrupting data collection mid-run.

BMS cutoff when a probe module powers up on the LabQuest 2

Certain sensors — particularly high-draw probes like dissolved oxygen or SpectroVis optical units — pull a sharp current spike the instant they initialise. On a degraded original cell, that spike pushes instantaneous draw past the BMS trip threshold, and the unit shuts down before data collection begins. A fresh cell with full capacity handles the inrush without crossing the cutoff. If shutdown still occurs after fitting this battery, check the probe cable for a bent pin causing a partial short at the sensor port.

LabQuest 2 showing unstable battery percentage across reboots

After fitting a new cell, the fuel gauge indicator on the LabQuest 2 may jump between readings — showing 80% one boot and 45% the next. This happens because the onboard voltage-threshold indicator is still calibrated to the wear curve of the old cell. The fix is to let the device discharge to the low-battery warning, charge it back to full without interruption, then run the calibration menu cycle once more. After that sequence the percentage reading stabilises to reflect the actual state of the new cell.