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

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

This 7.2V, 2000mAh Li-ion battery replaces the original power cell in the Electrolux Osiris cordless stick vacuum. It fits the Osiris range including model references 900258195, RX7-1-TM, and 900277268, among others. Voltage and capacity match OEM spec exactly — no modifications needed to fit the battery compartment.

• Osiris platform compatibility: These Osiris models share the same 7.2V power rail, battery form factor, and BMS handshake protocol. The connector and cell configuration are consistent across the range, so one battery covers the full listed model group without adapter or modification.
• Bench tested on actual hardware: We ran this battery through charge and discharge cycles on Osiris hardware. The BMS responded correctly to the charger handshake, held voltage across load cycles, and triggered cutoff at the expected threshold without false trips.
• Dock charging practice on Osiris vacuums: Do not leave the Osiris sitting on the charging dock continuously between uses. Cordless vacuums held on permanent trickle charge develop capacity fade significantly faster than those charged only when depleted. Charge to full, then remove from the dock.

Suction dropping before the battery indicator reaches low

On the Osiris, suction loss often happens before the battery indicator signals a problem. The motor draws harder to compensate for a restricted airflow path — a partially blocked filter is the most common trigger. That increased draw causes the battery voltage to sag under load even when charge capacity looks normal. Clean or replace the filter first, then retest suction at full charge.

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

This is a BMS overcurrent trip, not a dead battery. When the Osiris motor sustains a restricted suction path — blocked brush roll, clogged filter, or sealed intake — current draw spikes above the BMS threshold and the battery disconnects to protect the cells. The pack recovers once internal temperature drops, which is why a short pause brings it back. Clear the restriction and verify input voltage reads at least 7.2V before the next run.