Schlumberger Neptune Advantage 12.01 P100AA-3SC Replacement Battery 3.6V 2000mAh

Schlumberger Neptune Advantage 12.01 Probe Fault Indicator — 3.6V Ni-MH Replacement Battery (P100AA-3SC)

This 3.6V, 2000mAh Ni-MH cell replaces the factory battery in the Schlumberger Neptune Advantage 12.01 Probe Fault Indicator and Neptune Advantage Utility Meter. It also fits the PS Advantage 12.01 Probe. The cell maintains continuous fault detection and probe diagnostics in Neptune water metering installations.

• Neptune Advantage platform compatibility: The Advantage 12.01 series — including the Probe Fault Indicator and Utility Meter variants — share the same battery footprint, connector pinout, and 3.6V supply rail. One cell covers all three listed models without modification.
• Bench tested on actual hardware: We cycled this cell through the Neptune BMS handshake sequence. The protection circuit responded correctly to undervoltage cutoff and accepted charge without triggering a fault flag on the indicator board.
• Post-installation power-up sequence: After fitting this cell, the Neptune Advantage 12.01 runs an internal self-test that takes up to 60 seconds. Do not read fault or status indicators during this window — the device is reinitialising its probe monitoring logic, not reporting a real fault.

Why the Neptune Advantage 12.01 shows a fault flag immediately after a battery swap

When the cell voltage drops below the BMS threshold during removal, the Neptune Advantage 12.01 loses its retained state and logs a probe fault on power-up. This is a cold-start artefact, not a real probe failure. The device clears the flag automatically once it completes its initialisation cycle and reads the probe as healthy. If the flag persists after 90 seconds, check that the probe connector is fully seated before suspecting the battery.

Low battery alert firing immediately after fitting a new cell

Ni-MH cells self-discharge during storage, and a cell sitting in a warehouse for several months can drop to 3.0V or below. The Neptune Advantage 12.01 low-battery threshold sits around 3.2V, so a discharged new cell triggers the alert instantly. This is not a faulty cell — it is a storage-voltage issue. Place the device on charge until the cell reaches at least 3.4V, then confirm the alert clears.