Cub Cadet BAT6000A 25.6V Lawn Keeper 3000 Replacement Battery

Cub Cadet Lawn Keeper 3000 / XR3 Series — 25.6V LiFePO4 Replacement Battery (BAT6000A)

This is a 25.6V LiFePO4 replacement battery rated at 6000mAh (153.6Wh) for the Cub Cadet Lawn Keeper 3000, XR3 3000, XR3 4000, and XR3 5000 series cordless mowers. It replaces OEM part numbers BAT6000A, BAT6001B, BAT6000C, MRK6103A, and MRK6105A. LiFePO4 chemistry holds a flatter discharge curve than standard lithium-ion, which matters when the blade motor draws hard through thick grass.

• XR3 series platform fit: The Lawn Keeper 3000 and XR3 3000–5000 share the same 25.6V battery rail, connector pinout, and BMS handshake protocol — one battery SKU covers the full range without modification.
• Bench tested on actual hardware: We ran this pack through simulated blade-motor inrush cycles and monitored the BMS for overcurrent trips. The protection circuit held stable across repeated high-draw pulses without nuisance cutoff.
• Seasonal storage tip: Before the first cut of spring, bring the battery indoors overnight if ambient temps are below 10°C. Cold LiFePO4 cells carry higher internal resistance, and the blade motor's startup inrush can trip the BMS on a pack that hasn't warmed up.

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

When the Lawn Keeper 3000 hits dense or wet grass, the blade motor inrush current spikes sharply. If that spike exceeds the BMS overcurrent threshold — common when the battery is cold or the cells are new — the pack cuts out momentarily to protect the cells. This is a protection event, not a fault. On new LiFePO4 cells, the internal resistance drops after five to eight full charge cycles, which reduces inrush-triggered cutoffs significantly. If cutouts persist beyond that break-in window, check that the battery contacts are clean and seated fully in the bay.

Charger showing a fault light after the mower sat unused all winter

LiFePO4 cells self-discharge slowly over months of storage, and if the pack voltage drops below roughly 20V the charger's acceptance circuit may refuse to start a charge cycle — it reads the pack as damaged rather than just deeply discharged. Remove the battery, let it sit at room temperature for two hours, then reconnect it to the charger. Most OEM and third-party chargers for this platform will re-accept the pack once cell temperature normalises and the BMS resets its fault latch. If the charger still shows a fault after two connection attempts, check the charger LED sequence against the manual — a solid red with no blinking usually indicates a true BMS lockout requiring a reset at 25.6V nominal input.