Lawmate PV-700 Replacement Battery 3.7V 1800mAh Li-ion

Lawmate PV-700 / PV-1000 Series — 3.7V Li-ion Replacement Battery

This 3.7V 1800mAh Li-ion cell replaces the original battery in the Lawmate PV-700, PV-800, PV-806, and PV-1000 portable video recording and playback devices. It matches the original voltage and physical footprint at 53.00 × 35.30 × 11.00mm. Capacity is 6.66Wh — identical to the factory specification.

• PV-700 through PV-1000 compatibility: These four models share the same battery bay dimensions, 3.7V single-cell architecture, and connector pinout. The BMS handshake is identical across the series, so the same cell works in all four without modification.
• Bench tested on actual hardware: We ran charge and discharge cycles on PV-series units and confirmed the BMS accepted full charge without triggering an overcharge cutoff. Cell voltage held stable at 4.18V at full charge, and the protection circuit tripped correctly at the low-voltage threshold.
• First charge after deep discharge: If the device has been stored flat for weeks, connect the charger and leave it for 30 minutes before attempting to power on. The PV series enters a deep-discharge protection state that requires a slow trickle-in before the BMS allows normal current flow.

Battery percentage jumping after cell swap on PV-series devices

The PV-700 and its siblings use a voltage-threshold method to estimate charge level. After fitting a new cell, the firmware's stored voltage reference no longer matches the new cell's actual discharge curve. This causes the indicator to jump — sometimes showing full, then dropping suddenly. Running two full charge-discharge cycles recalibrates the thresholds and stabilises the readout.

Playback cutting out before the battery indicator shows empty

The video output circuit and audio amplifier draw peak current during playback. As a degraded or deeply cycled cell approaches the end of its discharge curve, voltage sags under that load before the indicator catches up. The device shuts down to protect the circuit even though the display still shows charge remaining. A fresh 1800mAh cell with a lower internal resistance reduces that voltage sag and pushes the actual cutoff point later in the discharge cycle.