About this replacement
Sencor SRV 6250 / SRV 8250 / SRV 9250 — 14.4V Li-ion Replacement Battery (BONA18650-MF1)
This 14.4V 2600mAh Li-ion battery pack replaces the original power cell in the Sencor SRV 6250, SRV 8250, and SRV 9250 cordless vacuum cleaners. It uses the same 4-cell 18650 configuration as the factory unit and matches the original BMS handshake required by Sencor chargers. Capacity is 2600mAh — identical to the OEM specification.
- SRV 6250, 8250, and 9250 compatibility: These three models share the same 14.4V battery bay, connector pinout, and BMS communication protocol. A single cell format — 4INR19/66 — covers all variants, which is why one replacement fits the entire lineup without modification.
- Bench tested on actual hardware: We ran this pack on the SRV 6250 motor platform and logged the BMS response under full suction load. The protection circuit held steady at rated draw and tripped correctly when we simulated a blocked filter — no false cutoffs under normal use.
- Dock charging behaviour on Sencor vacuums: Do not leave the vacuum sitting on the charging dock between every use. Sencor's dock delivers a trickle current when full, and repeated trickle charging accelerates capacity fade in Li-ion cells. Charge when depleted and remove from the dock once full.
Suction dropping before the battery indicator reaches low
On the SRV series, suction loss usually happens at the motor, not the battery. When the filter is partially blocked, the motor works harder, draws more current than rated, and the BMS drops output voltage to protect the cells — even if the indicator still shows charge remaining. The vacuum feels like it is losing power, but the battery is responding correctly to an overcurrent condition. Clean or replace the filter first before concluding the battery is at fault.
Motor cuts out mid-clean then restarts after a few seconds
This is a BMS overcurrent trip, not a dead battery. Sustained restricted airflow — from a packed dust cup or clogged filter — pushes motor draw above the BMS threshold, and the circuit opens to protect the cells. After a short pause, the BMS resets and the vacuum starts again. Empty the dust cup, clear the filter, then restart. If the cutout repeats on a clean filter, check that the cell voltage reads at least 14.4V under load using a multimeter across the battery terminals.