Phase II Survey Instrument Replacement Battery 3.7V 3200mAh

Phase PHT6000 Series — 3.7V Li-ion Replacement Battery (PHT6000-941)

This 3.7V 3200mAh Li-ion cell replaces the original pack in Phase II, PHT6000, and PHT6000-941 survey instruments. It fits units used for land measurement, mapping, and construction site work where field sessions run long and a degraded original pack is no longer keeping up. Capacity figure is from the product specification — 11.84Wh.

• PHT6000 platform compatibility: The Phase II, PHT6000, and PHT6000-941 share the same battery bay dimensions, connector pinout, and BMS communication protocol — one pack covers the full range without modification.
• Bench tested on actual hardware: We ran this pack through the PHT6000 power-up sequence, including sensor initialisation. The BMS handled the current spike at probe power-up without tripping, and the instrument registered the pack and reported state-of-charge correctly.
• Post-install calibration cycle: After fitting this battery, run a full calibration cycle through the instrument menu before heading to site. The PHT6000 maps battery state during calibration — skip this step and you will see premature low-battery warnings during your first measurement session even with a full charge.

PHT6000 shutting down mid-measurement with a charged battery

When the PHT6000 initialises a probe or sensor module, it draws a short current spike that a degraded or discharged cell cannot sustain. The BMS reads the resulting voltage sag as a fault condition and cuts output to protect the cell. This happens even when the display shows a healthy charge percentage, because the indicator is reading resting voltage, not load voltage. Replacing the pack resolves it — the new cell sustains the initialisation spike without tripping the BMS.

Readings drifting or resetting during a logging session

Sustained sensor load during a long logging session draws a steady current that can cause voltage to sag below the instrument's operating threshold. When that happens, the PHT6000 briefly drops power to the sensor circuit, and any unsaved log data for that interval is lost or corrupted. This is not a firmware issue — it is the original pack no longer holding voltage under continuous draw. Check resting voltage before a session: a healthy cell should read 3.7V or above at rest before you start a multi-hour log.