25.9V Lizard M4 Replacement Battery 7800mAh 110Z03700A

Lizard M4 / M440 Series — 25.9V Li-ion Replacement Battery (110Z03700A)

This is a 25.9V, 7800mAh lithium-ion battery that replaces the original pack on Lizard M4, M440, M480, and M485 cordless lawn mowers. It uses OEM part number 110Z03700A (Typ B) and slots into the same bay with the same connector orientation. Capacity is 202.02Wh — matched to the original specification.

• M4 and M440 platform compatibility: These models share a 25.9V seven-cell Li-ion architecture with the same BMS handshake protocol and blade-motor connector. The battery slides into any of them without adapter hardware or firmware changes.
• Bench tested on actual hardware: We cycled this pack through repeated blade-start inrush events simulating thick-grass load conditions. The BMS held the voltage rail stable above 22V throughout and did not false-trip during motor start surges.
• Seasonal storage charge level: Store this battery at 50–60% charge — not full — if the mower will sit unused for more than six weeks. A fully charged Li-ion pack loses more capacity to calendar ageing than one stored at mid-state.

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

The M4 blade motor draws a sharp inrush current each time it bites into dense or wet grass — often two to three times the steady-state draw. If the pack's cells are cold or partially depleted, internal resistance spikes during that inrush event, and the BMS reads it as an overcurrent fault and cuts the output. This is not a faulty battery — it is the protection circuit doing its job. Let the mower sit for five minutes to allow the BMS to reset, then resume cutting at a slower pace across dense sections. After five conditioning cycles, internal resistance drops and the cutoff threshold becomes harder to reach.

Charger shows a fault light after the mower sat in the garage all winter

Li-ion cells self-discharge slowly over months. If the pack dropped below approximately 20V during storage, most chargers will refuse to begin a charge cycle — they see the low voltage as a damaged cell and lock out to prevent thermal runaway. This is a recoverable state. Use a charger with a recovery or "wake-up" mode, or leave the pack connected for 10–15 minutes — some chargers trickle a small current at 100–200mA to nudge the cells above the acceptance threshold before switching to full charge. If the pack recovers past 22V, the charger will take over normally.