Bosch 11021499 Cordless Vacuum Replacement Battery 18.0V 2600mAh

Bosch 11021499 / 11021520 Series — 18.0V Li-ion Replacement Battery (908BPV180)

This 18.0V 2600mAh Li-ion battery replaces the original pack in Bosch cordless handheld vacuum cleaners including the 11021499, 11021520, 11038976, and 11038978. It matches the voltage and BMS communication expected by the Bosch charging platform. When the original battery no longer holds a charge or stops accepting one, this replacement restores the vacuum to working order.

• 11021499 and 11021520 platform compatibility: These models share the same 18.0V battery bay, connector pinout, and BMS handshake protocol. One pack fits across the range without adapter or modification.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on the Bosch charger. The BMS negotiated correctly, accepted a full charge without fault codes, and held voltage under sustained motor load without tripping overcurrent protection.
• Dock charging behaviour on cordless vacuums: Do not leave the vacuum sitting on the dock permanently. Cordless vacs on continuous dock charge develop capacity fade faster than units charged only when depleted. Charge to full, then remove from the dock.

Suction dropping before the battery indicator reaches low

This happens when motor draw exceeds what the cell can sustain under load, causing voltage to sag before the indicator registers a low state. A partially blocked filter forces the motor to pull harder than rated, which accelerates the sag. The BMS reads the voltage drop and throttles output to protect the cells. Clean the filter first — if suction holds steady after that, the cell was fine and the restriction was the cause.

Motor cutting out mid-clean and then recovering after a pause

This is a BMS overcurrent trip, not a dead battery. When suction is restricted — blocked nozzle, clogged filter, or hair-wrapped brush roll — the motor stalls slightly and current spikes above the BMS threshold. The BMS cuts power to protect the cells, then resets once current drops. Clear the blockage and check that the filter is clean before assuming the battery is at fault. After clearing, restart the vacuum and confirm it runs without cutting out.