About this replacement
Flymo Cordless Multitrim CT250X — 12.8V LiFePO4 Replacement Battery (9648645-25)
This is a 12.8V 6000mAh LiFePO4 replacement battery for the Flymo Cordless Multitrim CT250X and Contour PowerPlus Cordless CCT250 string trimmers. It matches the OEM part number 9648645-25 and slots into the same battery bay as the original pack. Capacity is 6000mAh (76.8Wh), identical to factory spec.
- CT250X and CCT250 compatibility: Both trimmers run the same 12.8V LiFePO4 platform and share the 9648645-25 connector and BMS handshake. The cutting head motor draws from the same voltage rail, so one battery design covers the full range without modification.
- Bench tested on actual hardware: We cycled this pack through repeated blade-start events under simulated thick-grass load. The BMS held the voltage rail steady through motor inrush and tripped cleanly at the thermal threshold without latching off permanently.
- Cold-weather start protocol: LiFePO4 cells still experience higher internal resistance below 10°C. If the trimmer has been stored in a cold garage, bring the battery indoors for several hours before use — blade motor inrush on a cold pack can trip the BMS on the first pull.
BMS cutoff on thick-grass or wet-grass blade load
The CT250X motor draws a sharp inrush current every time the blade engages dense or wet vegetation. If the BMS reads that spike as exceeding its protection threshold, it cuts power instantly. This is a protective response, not a battery fault. Let the trimmer sit for 30 seconds, then restart — the BMS resets automatically once the overcurrent condition clears.
Charger showing a fault light after the trimmer sat in storage all winter
LiFePO4 cells self-discharge slowly over months of inactivity. If the pack voltage drops below the charger's acceptance threshold — typically around 10V on this platform — the charger will flash a fault indicator and refuse to charge. Some chargers have a recovery or trickle mode; activate it and leave the pack connected for up to two hours. If the charger accepts the pack, it will transition to normal charge mode once the cell voltage climbs back above the threshold.