Black+Decker FV18LA Replacement Battery 18.5V 2000mAh

Black+Decker FV18LA — 18.5V Li-ion Replacement Battery (INR18650-5S1P)

This 18.5V 2000mAh Li-ion battery replaces the original INR18650-5S1P cell pack in the Black+Decker FV18LA cordless handheld vacuum. It fits directly into the FV18LA and restores suction power for cleaning floors, furniture, and tight spaces. Voltage and capacity match the original spec — 18.5V, 2000mAh (37Wh).

• FV18LA platform fit: The FV18LA runs a 5S1P 18650 cell configuration to hit the 18.5V rail the motor controller expects. Swapping a lower-voltage pack causes the motor to underperform under load — this replacement holds the correct cell count and connector orientation for the vacuum's BMS handshake.
• Bench tested on actual hardware: We ran this cell pack through charge and discharge cycles on the FV18LA platform. The BMS accepted charge without fault codes, and the motor drew current within the expected range across both hard-floor and carpet-load simulations.
• Dock charging habit on the FV18LA: Do not leave the FV18LA sitting on the charging dock permanently. Continuous dock connection applies a trickle charge that degrades Li-ion cells faster than intermittent charge cycles. Charge to full, then remove the vacuum from the dock until the next use.

Cordless vacuum losing suction before the battery indicator reaches low

The FV18LA motor draws more current when airflow is restricted — a partially blocked filter forces the motor to work harder, pulling the cell voltage down under load even when the battery still reads mid-charge. The BMS reads this voltage sag as a near-depleted pack and throttles output. Clean or replace the filter first — if suction recovers, the battery was not the issue. If sag continues with a clean filter and a fresh charge, the cell pack has degraded below usable discharge capacity.

Motor cutting out mid-use and then recovering after a short pause

This is an overcurrent trip from the BMS — not a dead battery. Sustained restricted airflow (blocked nozzle, clogged filter, or hair wrap on the intake) causes the motor to spike current beyond the BMS threshold, which shuts the output to protect the cells. After a short rest the BMS resets and power returns. Check the intake path and filter before replacing the battery. If the trip happens immediately on a fresh charge with a clear filter, measure the pack voltage at rest — it should read between 20.5V and 21.0V fully charged on an 18.5V nominal 5S cell pack.