Lizard M4 Replacement Battery 25.2V 10200mAh Li-ion

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

This is a 25.2V, 10200mAh (257.04Wh) Li-ion battery pack for the Lizard M4, M440, M480, and M485 cordless lawn mowers. It slots into the same battery bay as the original and communicates with the mower's onboard BMS. Fit this when the original pack no longer holds charge or fails mid-cut.

• M4 platform compatibility: The M4, M440, M480, and M485 all share the same 25.2V battery rail and connector format. The blade motor and control board expect the same BMS handshake, so one pack covers the full range without modification.
• Bench tested on actual hardware: We ran this pack through full charge and discharge cycles on the M4 platform. The BMS handled inrush current from a cold motor start without tripping, and cell balancing stayed within spec across all cycles.
• First-use seasonal prep: If the mower has sat unused through winter, bring the battery indoors overnight before the first spring cut. Below 10°C, Li-ion internal resistance rises sharply — the blade motor's inrush current on startup can trip the BMS on a cold pack before the cells have warmed to operating temperature.

BMS cutoff during thick-grass or wet-grass blade load

When the blade motor hits dense or wet grass, current draw spikes well above steady-state levels. If the BMS reads this spike as an overcurrent event, it cuts power to protect the cells. This is more likely on a new pack in the first few cycles before the cells have fully conditioned. If it happens consistently, reduce forward speed through the heavy section and let the deck clear before pushing forward again. After five full charge-discharge cycles, the BMS threshold calibrates more accurately to the motor's real load curve.

Charger shows fault light after the mower sat all winter

A pack stored discharged over winter can drop below the charger's minimum acceptance voltage — typically around 20V on 25.2V Li-ion systems. When this happens, the charger reads the pack as faulty and refuses to begin a charge cycle. Connect the pack to the charger and leave it for 15–20 minutes without interruption; some chargers will attempt a slow recovery trickle before switching to normal charge mode. If the fault light stays on after 30 minutes, check that the battery terminal contacts are clean and the pack voltage with a multimeter — a reading below 18V usually means one or more cells have dropped too low to recover.