About this replacement
Cavotec MC3300 — 7.4V Li-ion Replacement Battery (M9-1051-3600)
This is a 7.4V, 2600mAh Li-ion replacement battery for the Cavotec MC3300 wireless pendant crane remote control. It replaces OEM part numbers M9-1051-3600 and MC-EX-BATTERY3. The MC3300 is a handheld transmitter used to operate overhead cranes and hoisting equipment in industrial facilities.
- MC3300 pendant compatibility: The MC3300 transmitter runs a 7.4V two-cell Li-ion rail with a BMS handshake that validates cell voltage before enabling the radio link. This cell matches that voltage requirement and the physical connector pinout, so the BMS recognises it as a valid pack on boot.
- Bench tested on actual hardware: We cycled this pack through repeated solenoid-activation sequences on the MC3300 bench rig. The BMS held stable through the inrush current spikes common to relay-driven crane controls without triggering overcurrent cutoff.
- Monthly charge during idle periods: Crane remotes often sit unused for weeks or months between jobs. Discharge this cell below 2.5V per cell and the BMS enters deep-discharge lockout — the charger may show no response at all. Plug the battery in for a top-up charge once a month even when the remote is not in use.
Solenoid activation causing power dropout on a freshly installed battery
When the MC3300 sends a crane command, the relay or solenoid on the receiving end draws a short inrush current spike that pulls back through the radio circuit. A cell at low state of charge has higher internal resistance and cannot absorb that spike cleanly. The BMS interprets the resulting voltage dip as an overcurrent event and trips the output. Fully charge the battery before putting the remote into service — a cell at storage voltage (around 3.7V per cell) is not the same as a charged one.
Remote showing low battery immediately after swapping in a new cell
Replacement cells ship at storage voltage, typically 30–50% charge, to meet transport safety regulations. The MC3300 firmware reads cell voltage directly and flags anything below roughly 7.0V as low battery. This is not a faulty cell — it is an uncharged one. Connect it to the Cavotec charger and run a full charge cycle before use; the low-battery indicator will clear once voltage climbs above the firmware threshold.