About this replacement
AEG 900165577 / AG901 Series — 12V Ni-MH Replacement Battery (4055132304-2)
This is a 12V 2200mAh Ni-MH replacement battery for AEG cordless vacuum cleaners. It fits the 900165577, AG901, 900165579, AG902, and over 43 additional AEG cordless vacuum models. Voltage and capacity match the original specification — 12V, 2200mAh, 26.4Wh.
- AG901 / AG902 platform fit: These models share a common 12V Ni-MH cell arrangement and connector housing. The motor controller draws from the same voltage rail across the range, so one battery cell pack covers the group without modification.
- Bench tested on actual hardware: We ran this pack through full charge and discharge cycles on an AG901 chassis. The BMS held steady across the draw curve, and the motor controller accepted the pack without error codes or shutdown events.
- Dock charging habit for Ni-MH cells: Do not leave the vacuum sitting on the charging dock between uses. Ni-MH chemistry in continuous trickle charge degrades cell capacity faster than Li-ion. Charge the pack to full, then remove it from the dock until the next use.
Cordless vacuum losing suction before the battery indicator reaches low
This happens when the motor is working harder than rated — usually caused by a partially blocked filter or clogged cyclone chamber. The motor draws more current to maintain airflow, which pulls the cell voltage down early. The battery indicator reads remaining charge, not actual voltage under load, so it can show mid-charge while suction is already weak. Clear the filter first, then retest — if suction returns, the pack is fine.
Motor cuts out mid-clean then recovers after a few seconds
This is an overcurrent trip from the BMS, not a dead battery. It fires when sustained suction restriction — blocked filter, sealed nozzle, or heavy carpet load — forces the motor to pull current beyond the pack's safe discharge threshold. The BMS cuts power briefly to protect the cells, then resets. Clean the filter and check the nozzle for blockages. If it still trips on a clear machine, the original cells may have degraded below the current threshold and replacement is the correct fix.