Akerstroms 940684-000E Replacement Battery 2.4V 3500mAh

Akerstroms 200J / MC98 Transmitters — 2.4V Ni-MH Replacement Battery (940684-000E)

This is a 2.4V, 3500mAh Ni-MH replacement battery for Akerstroms 200J and MC98 industrial crane remote control transmitters. It replaces OEM part numbers 940684-000E, 940684-000, and 170.2151. The battery fits directly into the transmitter housing and restores full operating capacity to the remote control system.

• 200J and MC98 transmitter compatibility: Both the 200J and MC98 series share the same 2.4V two-cell Ni-MH pack format, connector pinout, and charge termination logic. The BMS on each transmitter uses delta-V cutoff to detect full charge — the cell chemistry here matches that threshold behaviour exactly.
• Bench tested on actual hardware: We ran this pack through charge cycles on a 200J transmitter and confirmed the BMS accepted charge without error flags, held voltage under solenoid activation load, and showed no unexpected thermal cutoff events.
• Infrequent-use charging protocol: If the transmitter sits unused for more than four weeks, connect it to the charger for a full cycle before returning it to service. Ni-MH cells in crane remotes left at partial state of charge self-discharge steadily — cells that drop below the BMS recovery threshold may read as faulty even after reconnecting to a charger.

Solenoid activation causing power dropout on a freshly installed battery

When a crane remote triggers a solenoid or relay, the inrush current spike can briefly exceed what a partially charged Ni-MH pack can deliver without a voltage sag. If the transmitter browns out or resets the moment you activate a control function, the cell voltage is likely too low to handle the load. A fully charged 2.4V Ni-MH pack should hold above 2.2V under that inrush pulse. Charge the battery completely before testing — a resting voltage of 2.4–2.5V at the terminals confirms the pack is ready for load.

Remote showing low-battery warning immediately after new cell install

Replacement Ni-MH cells ship at storage voltage, typically 1.0–1.1V per cell, which puts the pack well below the transmitter's normal operating threshold. The low-battery indicator triggers because the transmitter reads that storage voltage as a depleted cell, not a fault. This is not a defective battery. Place the transmitter on charge for a full cycle — once the pack reaches 2.4V, the low-battery warning clears and the remote operates normally.