Flymo 1200R 18V Replacement Battery 1500mAh Li-ion

Flymo 1200R Series — 18V Li-ion Replacement Battery

This 18V 1500mAh Li-ion battery replaces the original pack in the Flymo 1200R robotic lawn mower, including the 2013 and 2014 model years. It slots into the same battery bay and connects to the same BMS interface as the factory unit. Capacity is 27Wh, matching the original specification.

• 1200R platform fit: The 1200R, 1200R 2013, and 1200R 2014 variants all share the same 18V battery bay, connector pinout, and BMS handshake protocol — one pack covers the full range without modification.
• Bench tested on actual hardware: We ran this pack through full charge and discharge cycles, monitoring BMS cutoff behaviour under simulated blade-motor inrush loads. The protection circuit held within expected trip thresholds across all test runs.
• Seasonal storage tip: If the mower sits unused through winter, remove the battery and store it at 40–60% charge. A fully discharged Li-ion pack left for several months can drop below the charger's acceptance voltage, requiring a recovery charge before normal use resumes.

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

The 1200R's blade motor draws significantly more current when cutting dense or wet grass than it does on a dry, short lawn. If the inrush current spike exceeds the BMS trip threshold, the pack shuts off to protect the cells. This happens more often on a new or cold battery, where internal resistance is slightly higher. Once the pack warms through a few cycles, the trip threshold is less likely to be reached under normal conditions.

Charger showing a fault light after the mower sat through winter

If the battery self-discharged below roughly 2.5V per cell during a long storage period, the charger may refuse to start a normal charge cycle and display a fault or error indicator. This is a low-voltage lockout — the BMS blocks the charger until cells are above the acceptance threshold. Some chargers include a recovery or conditioning mode that applies a low-current trickle to bring the pack back up to acceptance voltage, typically around 14–15V total. If your charger lacks that mode, a dedicated Li-ion recovery charger set to trickle mode can bring the pack back to a chargeable state.