Sencor SRV 9550BK Replacement Battery 14.8V 5200mAh

Sencor SRV 9550BK — 14.8V Li-ion Replacement Battery (SRX 0507)

This is a 14.8V, 5200mAh (76.96Wh) lithium-ion battery for the Sencor SRV 9550BK cordless stick vacuum. It replaces OEM part SRX 0507 and fits the same connector and BMS interface as the original pack. Capacity figure is taken from the product specification — not estimated from runtime.

• SRV 9550BK platform fit: The SRV 9550BK runs a 14.8V four-cell Li-ion architecture. This replacement matches that cell count, voltage rail, and the connector pinout the vacuum's motor controller expects. Swapping to a mismatched voltage pack will either prevent startup or trip the motor driver's undervoltage latch.
• Bench tested on actual hardware: We cycled this pack through full charge and load discharge while monitoring BMS cutoff thresholds. The protection circuit tripped correctly on overcurrent and recovered cleanly after load removal — consistent with the OEM pack behaviour on the SRV 9550BK motor controller.
• Dock charging on the SRV 9550BK: Do not leave the vacuum sitting on the charging dock continuously. The SRV 9550BK's charger does not apply a true maintenance mode — prolonged dock contact applies a trickle that accelerates cell degradation. Charge to full, then remove from the dock.

Suction dropping before the battery indicator reaches low

The SRV 9550BK's motor draws higher current when the filter is partially blocked or the dust cup is near full. Under that load, a degraded cell group sags below the motor controller's minimum operating voltage before the fuel gauge registers low. The controller then reduces motor speed to protect the cells — which reads to the user as suction loss, not a battery warning. Clean the filter and empty the dust cup first; if suction then holds steady, the battery pack is functioning correctly. If suction still drops with a clean filter, the cells have lost enough capacity that voltage sag is occurring at normal draw — replace the pack.

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

This is a BMS overcurrent trip, not a total battery failure. It happens most often when the vacuum is pushed hard across thick carpet with a restricted airflow path — the motor pulls sustained current above the BMS threshold, and the protection circuit opens. The pack resets once temperature and current drop, which is why the vacuum restarts after sitting for thirty to sixty seconds. Check the filter condition and clear any blockage at the brush head first. If trips continue on a clean, unobstructed path, measure pack voltage at rest — a healthy 14.8V four-cell pack should read between 16.4V and 16.8V fully charged.