Bosch BHN20L 18V Replacement Battery 2500mAh Li-ion

Bosch BHN20L / Move 20V Series — 18V Li-ion Replacement Battery (801BPV180-01)

This is an 18V Li-ion battery rated at 2500mAh (45Wh), replacing OEM part 801BPV180-01. It fits the Bosch BHN20L, BHN20L/04, and Move 20V cordless handheld vacuums. Same voltage, same connector orientation, same BMS communication protocol as the original cell.

• BHN20L and Move 20V platform: These models share the same 18V battery bay, connector pinout, and BMS handshake requirements. Swapping between them uses the same cell — Bosch standardised the interface across this vacuum line to simplify servicing.
• Bench tested on actual hardware: We ran this battery on a BHN20L under sustained suction load and monitored BMS response. Voltage held steady across the discharge curve and the protection circuit triggered correctly at low-cell threshold — no premature cutoff.
• Dock charging habit on cordless vacuums: Do not leave the BHN20L sitting on the charging dock after the battery reaches full. Continuous dock contact on this platform delivers a low-level trickle that accelerates capacity fade. Charge to full, then remove from the dock.

Suction dropping before the battery indicator hits low

The BHN20L motor draws more current when airflow is restricted — a partially blocked filter forces the motor to work harder, pulling amps beyond its rated draw. The BMS reads this elevated current as a potential fault and reduces output voltage to protect the cell. The result is weaker suction even though the battery still shows charge. Clean or replace the filter first — if suction restores, the battery was never the issue.

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 sustained against a blockage or dense carpet pile, current spikes briefly above the protection threshold. The BMS shuts the output, waits for the cell temperature and load reading to normalise, then re-enables. It is a repeating cycle until the restriction is cleared. Remove any blockage from the nozzle and inlet path, then resume — the BMS will reset and hold output voltage without tripping.