Black&Decker FHV1200 Replacement Battery 11.1V 5200mAh

Black&Decker FHV1200 TYPE 1 — 11.1V Li-ion Replacement Battery (INR18650-3S2P)

This is an 11.1V, 5200mAh lithium-ion replacement battery for the Black&Decker FHV1200 TYPE 1 cordless handheld vacuum. It replaces the original INR18650-3S2P pack using the same 3S2P 18650 cell configuration. When the original pack degrades and suction drops noticeably, swapping this battery restores the motor's full voltage supply.

• FHV1200 TYPE 1 fit: The TYPE 1 variant uses a specific connector orientation and BMS handshake tied to the INR18650-3S2P cell format. This replacement matches the 3S2P cell layout, connector, and communication protocol that the FHV1200's charge management expects.
• Bench tested on actual hardware: We ran this pack through full charge and discharge cycles on the FHV1200 motor platform. The BMS held stable across floor and upholstery attachments, with no false overcurrent trips under normal suction loads.
• Dock charging on the FHV1200: Do not leave the FHV1200 sitting on the charging dock permanently. Cordless vacuums on continuous dock power develop capacity fade significantly faster than packs charged only when depleted. Charge to full, then remove the unit from the dock.

Suction dropping before the battery indicator reaches low

This is a voltage sag issue, not a capacity issue. When the FHV1200 motor encounters restricted airflow — a partially blocked filter or a full dust cup — it pulls more current than rated. That extra draw drops cell voltage faster than the indicator tracks, so the motor slows while the LED still shows charge remaining. Clean the filter first. If sag continues on a new filter with a fresh battery, check the dust cup seal for gaps that reduce airflow pressure at the motor inlet.

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

This is a BMS overcurrent trip, not a dead battery. The FHV1200's battery management system cuts power when sustained current draw exceeds the safe threshold — typically triggered by prolonged restricted suction. After a short pause, the BMS resets and the motor starts again. The fix is to clear the restriction: remove the filter, tap out debris, and confirm the dust cup is not more than half full. If the cutout persists on a clean filter, verify cell voltage sits at or above 11.1V on a full charge before ruling out a deeper fault.