AEG Electrolux FM 3.6V Cordless Vacuum Replacement Battery 3600mAh

AEG Electrolux FM Series — 3.6V Ni-MH Replacement Battery (900055103)

This is a 3.6V, 3600mAh Ni-MH replacement battery for the AEG Electrolux FM series cordless vacuum cleaner. It replaces OEM part number 900055103. When the original cell degrades and the vacuum loses suction power quickly, this cell restores full operating capacity.

• FM series compatibility: The FM series vacuums share a single battery platform — same 3.6V rail, same connector format, same BMS communication protocol. This cell fits directly without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the FM platform. The BMS accepted the cell without fault flags, voltage held steady under motor load, and the charger handshake completed normally.
• Dock charging habit matters: Do not leave the FM vacuum on the charging dock permanently. Ni-MH cells on continuous trickle charge develop capacity fade faster than cells charged only when depleted. Charge to full, then remove from the dock.

Suction dropping before the battery indicator reaches low

This is one of the most common complaints on the FM series, and it is rarely a battery problem first. A partially blocked filter forces the motor to draw more current than rated, which pulls cell voltage down prematurely. The battery indicator reads remaining charge, not available current — so the light stays green while suction has already fallen. Clean or replace the filter first, then retest.

Motor cuts out mid-use then restarts after a short pause

This is a BMS overcurrent trip, not a dead battery. When suction is sustained against a blockage — hair wrap around the brush roll, a clogged filter, or a blocked nozzle — current draw spikes above the BMS threshold. The BMS disconnects the cell to protect it, and it resets after the cell cools slightly. Clear the blockage, check the filter, and confirm the brush roll spins freely before restarting.