Lizard M4 25.2V Cordless Lawn Mower Replacement Battery 6900mAh

Lizard M4 / M440 / M480 / M485 Series — 25.2V Li-ion Replacement Battery

This is a 25.2V 6900mAh Li-ion battery that replaces the original pack on Lizard M4, M440, M480, and M485 cordless lawn mowers. It slots into the same battery bay and communicates with the mower's onboard BMS using the original connector and cell configuration. Capacity is 6900mAh (173.88Wh), matching the stock specification.

• M4 series compatibility: The M4, M440, M480, and M485 share the same 25.2V battery platform — same connector housing, same cell count, same BMS handshake protocol. One replacement pack covers all of them without modification.
• Bench tested on actual hardware: We ran this pack through repeated high-draw discharge cycles simulating blade motor inrush. The BMS held cutoff thresholds correctly and recovered without error codes across all test runs.
• First spring use tip: If the mower has been stored over winter, bring the battery indoors overnight before the first mow. Below 10°C, Li-ion internal resistance rises sharply — cold cells under blade motor inrush load can trigger a BMS trip before the mower cuts a single strip.

BMS cutoff on thick-grass and wet-grass blade load

The M4 series blade motor draws a large inrush current every time it spins up against resistance — wet grass and overgrown patches make that spike worse. If the BMS reads a current spike beyond its protection threshold, it trips and cuts power to protect the cells. This is not a battery fault. Letting the mower move at a slower pace through dense patches keeps the motor load below the trip point and prevents mid-row shutdowns.

Charger showing fault light after mower sat in garage all winter

Li-ion cells self-discharge slowly in storage. After several months in a cold garage, a pack can drop below the charger's minimum acceptance voltage — typically around 20V on a 25.2V system. The charger reads this as a fault rather than a discharged cell and refuses to start a charge cycle. Some Lizard chargers include a recovery or boost mode; engage it for 10–15 minutes to bring the cell voltage up to the acceptance threshold, after which normal charging resumes.