Bosch P800SL Cordless Vacuum Replacement Battery 4.8V 2000mAh

Bosch P800SL — 4.8V Ni-MH Replacement Battery (1 609 200 922)

This is a 4.8V, 2000mAh Ni-MH replacement battery pack for the Bosch P800SL cordless handheld vacuum cleaner. It matches the original voltage and capacity spec, fitting directly into the P800SL battery compartment. OEM part numbers covered: 1 609 200 922, 1 609 390 002, and 4N1200SC-2L.

• P800SL platform fit: The P800SL runs a compact 4.8V four-cell Ni-MH stack. This replacement uses the same cell count and connector orientation, so the battery seats correctly and the vacuum's charge circuit recognises it without modification.
• Bench tested on actual hardware: We cycled this pack through discharge and recharge on the P800SL platform. The BMS accepted charge normally, voltage held steady under motor load, and the pack reached rated capacity within two break-in cycles.
• Dock charging discipline for Ni-MH cells: Do not leave the P800SL sitting on the charging dock permanently. Ni-MH cells in low-current continuous trickle charge accumulate heat and develop memory effect faster than Li-ion packs. Charge to full, then remove the vacuum from the dock.

Suction dropping before the battery indicator reaches low on the P800SL

The P800SL's motor draws more current when airflow is restricted — a partially blocked filter forces the motor to work harder at the same fan speed. This extra draw pulls cell voltage down faster than the indicator expects, so the vacuum feels weak while the gauge still shows charge. The BMS reads the pack as adequate because resting voltage recovers the moment load drops. Clean or replace the filter first — if suction recovers immediately, the pack is not the problem.

Motor cutting out mid-clean and then restarting after a short pause

This is a BMS overcurrent trip, not a dead battery. When sustained suction restriction causes current draw to spike beyond the pack's rated threshold, the BMS cuts output to protect the cells, then resets once temperature and current normalise. A worn or degraded original pack hits the trip threshold sooner because aged Ni-MH cells have higher internal resistance, which amplifies voltage sag under load. Swap to a fresh pack and clear any filter blockage — if the cutout stops, the original cells were the limiting factor.