Bosch BKS3003CN Replacement Battery 3.6V 3000mAh

Bosch BKS3003CN Series — 3.6V Ni-MH Replacement Battery (3-VR1.8CS VC1)

This is a 3.6V, 3000mAh Ni-MH replacement battery for the Bosch BKS3003CN cordless hand vacuum and related models including the VCAS010V00 and VC1. It replaces OEM part 3-VR1.8CS VC1. Rated at 10.8Wh, it restores full motor voltage to the suction unit after the original cell pack degrades.

• BKS3003CN, VCAS010V00 and VC1 series: These models share the same 3.6V single-rail motor circuit and use the same cell geometry and connector. One battery fits all of them because the BMS expects the same cutoff threshold and charge termination signal across the range.
• Bench tested on actual hardware: We cycled this cell pack through charge and discharge on the BKS3003CN motor circuit. The BMS accepted the replacement cells without fault codes, and delta-V termination on the charger cut off correctly at full capacity.
• Dock charging behaviour on Bosch hand vacuums: Do not leave the vacuum sitting on the charging dock after the charge cycle completes. Bosch hand vacuums on continuous dock charge develop capacity fade faster than units charged only when depleted. Charge to full and remove from the dock.

Cordless vacuum losing suction before the battery indicator reaches low

This happens when the motor draws more current than the cell pack can deliver cleanly — voltage sags under load even though the indicator still reads mid-range. On Ni-MH cells, a degraded pack loses internal resistance headroom first, so motor speed drops before the BMS trips the low-voltage cutoff. A partially blocked filter makes it worse by forcing the motor to sustain a higher draw against restricted airflow. Clear the filter and check that the new cell pack holds above 3.2V under load.

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

This is a BMS overcurrent trip, not a dead battery. When airflow is restricted — by a clogged filter or a blockage in the nozzle — the motor works harder and pulls current past the BMS threshold. The protection circuit opens, the motor stops, and once current demand drops the BMS resets. This cycle repeats until the restriction is cleared. Clean the filter before assuming the battery is at fault; if the cut-out stops after cleaning, the cell pack is fine.