Kobalt KB2540C-06 40V Lawn Mower Compatible Battery 6000mAh

Kobalt 16-Inch Mower KM-1640-06 — 40V Li-ion Replacement Battery (KB2540C-06)

This is a 40V lithium-ion replacement battery rated at 6000mAh (240Wh) for the Kobalt KM-1640-06 16-inch cordless mower. It also fits the KM 4040-06 19-inch, KM 2041B-06 20-inch, and additional 40V Max Kobalt mower platforms. Drop the original OEM part number KB2540C-06 into your search and this is the pack that comes back.

• Kobalt 40V Max mower platform: These mowers share a common 40V rail, connector footprint, and BMS handshake protocol across the KM-1640-06, KM 4040-06, and KM 2041B-06 lines. All three platforms draw motor inrush current through the same overcurrent threshold, so one pack covers the family. Also cross-references OEM part numbers KRC40-06, KRC60-06, and KRC840-03.
• Bench tested on actual hardware: We ran this pack through full discharge cycles on a KM-1640-06 deck with the blade engaged on thick grass simulation. The BMS handled motor-start inrush without tripping and held cell voltage steady above the low-voltage cutoff through the full cycle.
• First-use break-in on mower motor loads: Run two cutting sessions at partial deck load before tackling full-throttle thick-grass passes. This lets the BMS log the motor's inrush current signature and calibrate its overcurrent protection threshold before you throw a full-load start at it.

BMS cutoff on blade-engagement inrush surge

When the blade engages, the mower motor pulls a sharp inrush spike that can be three to five times its running current. A freshly installed or storage-cold pack sometimes interprets that spike as a fault and trips the BMS overcurrent protection before the blade is fully up to speed. The BMS resets automatically once the cell voltage recovers, but repeated trips on start-up indicate either a contact resistance problem at the rail or a pack that hasn't profiled the motor's inrush pattern yet. Two partial-load cycles typically train the BMS to accept the motor's normal start signature.

Charger showing red or blinking on a new pack after storage

Li-ion cells self-discharge during shipping and warehouse storage. If any cell drops below roughly 2.5V, the Kobalt charger's acceptance circuit won't recognise the pack as safe to charge and throws a red or blinking indicator instead of beginning a charge cycle. The fix is a brief recovery charge — some Kobalt chargers have a wake-up mode; if yours doesn't, leave the pack on the charger for 10–15 minutes and check again. If cells recover past the 3.0V acceptance threshold, the charger will switch to its normal charge sequence.