About this replacement
Sharp EC-A1R-P Series — 18V Li-ion Replacement Battery (BY-5SB)
This is an 18V 2000mAh lithium-ion replacement battery for the Sharp EC-A1R-P and related cordless stick vacuum models. It replaces OEM part numbers BY-5SB, BY-5SA, BY-5SBTW, and BY-5SB25. Use it when the original pack no longer holds enough charge to complete a full cleaning session.
- EC-A1R and EC-AP500 series compatibility: These models share the same 18V motor rail, battery connector, and BMS handshake protocol. A single cell pack covers the full range — the BMS communication signals are consistent across this vacuum platform.
- Bench tested on actual hardware: We cycled this pack through charge and discharge on the EC-A1R platform. The BMS negotiated correctly with the charger on first connection, and overcurrent cutoff triggered as expected under a simulated motor-stall condition.
- Dock charging habit on Sharp stick vacuums: Do not leave this vacuum on the charging dock permanently. These vacuums trickle-charge when docked continuously, and that sustained low-current charge degrades cell capacity faster than normal cycling. Charge to full, then remove from the dock.
Suction dropping before the battery indicator reaches low
This happens when the motor draws more current than the BMS is comfortable sustaining — often caused by a partially blocked filter, not a weak battery. Restricted airflow forces the motor to work harder, pulling current spikes that the BMS interprets as an overload. The result is voltage sag at the motor, which reads as weak suction even though the cell still has capacity. Clean or replace the filter first, then test suction again before assuming the battery is at fault.
Motor cutting out mid-clean and then recovering after a few seconds
This is a BMS overcurrent trip, not a dead battery. When suction is restricted — blocked nozzle, clogged filter, heavy carpet fibres — the motor stalls briefly and draws a current spike. The BMS cuts power to protect the cells, then resets once current normalises. Clear any blockage, check the filter, and resume use. If the cutout keeps happening on an open floor with a clean filter, charge the pack to full (18V at rest) and retest — a low cell may be triggering the threshold early.