AEG Electrolux Osiris 7.2V Replacement Battery 2600mAh

AEG Electrolux Osiris — 7.2V Li-ion Replacement Battery (S91-0400410-SU2)

This 7.2V, 2600mAh Li-ion battery pack replaces the original power cell in the AEG Electrolux Osiris cordless handheld vacuum cleaner. It fits the Osiris series including model references 900258195, RX7-1-TM, and 900277268, among others. Voltage and capacity match OEM specification exactly — no modifications needed to fit the battery compartment.

• Osiris series compatibility: These models share the same 7.2V power rail, physical form factor, and BMS handshake protocol. The replacement cell uses the same connector pinout and communication signals the Osiris charger expects, so the charging circuit recognises the pack without fault codes.
• Bench tested on actual hardware: We cycled this pack through full charge and discharge on an Osiris unit, monitoring BMS response across motor start, sustained suction load, and filter-restriction conditions. The BMS held within expected current limits and did not trigger a false overcurrent cutoff during any test phase.
• Dock charging habit for the Osiris: Do not leave the Osiris sitting on the charging dock between every use. Continuous trickle charging degrades Li-ion cell capacity significantly faster than charge-then-remove cycles. Charge fully, remove from the dock, and only return it when the battery is depleted.

Suction dropping before the battery indicator reaches low

This happens when the motor draws more current than the BMS allows under restricted airflow — not because the battery is empty. A partially blocked filter forces the motor to work harder, pulling current above the BMS overcurrent threshold. The BMS responds by reducing output voltage to protect the cells, which drops suction noticeably while the indicator still shows charge remaining. Clean or replace the filter first and test again — suction should stabilise at full strength through most of the charge cycle.

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

This is a BMS overcurrent trip, not a dead battery. When airflow is blocked — by a full dust container, clogged filter, or a floor nozzle obstruction — the motor draws a sustained current spike the BMS cannot allow. It cuts power to protect the cells, then resets once current demand drops. The fix is not a new battery. Empty the dust container, check the filter, and clear any nozzle blockage before restarting. If the cutout still occurs on a clean, unobstructed vacuum, check cell voltage at rest — it should read above 7.0V.