About this replacement
AEG Junior 3000 — 3.6V Ni-MH Replacement Battery (520104)
This is a 3.6V 3000mAh Ni-MH replacement battery for the AEG Junior 3000 cordless handheld vacuum cleaner. It replaces OEM part number 520104 and restores cordless cleaning function when the original cells have degraded. Capacity matches the factory specification at 10.8Wh.
- Junior 3000 compatibility: The Junior 3000 runs a single-cell Ni-MH pack at 3.6V. The connector pinout and cell count on this replacement match the original, so the charger circuit reads the pack correctly and delivers the right charge current without triggering a fault condition.
- Bench tested on actual hardware: We ran this cell through the AEG charger and confirmed the BMS accepted the pack, completed a full charge cycle, and held voltage across repeated discharge cycles under simulated motor load.
- Dock charging on the Junior 3000: Do not leave the vacuum sitting on the charging dock permanently. Ni-MH cells in compact vacuums like this one degrade significantly faster under continuous trickle charge. Charge to full, then remove from the dock.
Suction dropping before the battery indicator shows low
The Junior 3000 motor draws higher current when the filter is partially blocked. That extra draw pulls the cell voltage down faster than normal, causing the motor to lose speed — and suction — well before the battery indicator triggers. The indicator reads state of charge under a baseline load, not under a restricted-airflow load. Clean the filter first. If suction recovers, the battery is not the fault.
Motor cutting out mid-clean and then recovering after a short pause
This is a BMS overcurrent trip, not a flat battery. When suction is sustained against a blockage or a clogged filter, current through the cell spikes past the protection threshold and the BMS interrupts the circuit. A short pause lets the BMS reset and the motor restarts. Clear the filter and check the intake path for obstructions. If the cutout stops after cleaning the filter, the replacement cell is functioning correctly.