25.2V Dyson V11 Replacement Battery 4200mAh 299820

Dyson V11 Series — 25.2V Li-ion Replacement Battery (970145-02)

This is a 25.2V, 4200mAh lithium-ion replacement battery for the Dyson V11 cordless vacuum range. It fits the V11, V11 Absolute Pro, V11 Absolute Extra, V11 Absolute, and over twelve additional V11 variants. Swap it in when the original cell no longer holds charge or the vacuum shuts off mid-clean.

• V11 platform compatibility: All V11 models share the same 25.2V battery rail, connector housing, and BMS handshake protocol. One cell covers the full range because Dyson standardised the battery interface across every V11 variant from launch.
• Bench tested on actual hardware: We ran this cell on a V11 Absolute and monitored BMS communication throughout the charge cycle. The battery completed a full charge without fault flags, and the LCD power indicator on the vacuum updated correctly at each stage.
• Dock charging habit on the V11: Remove the vacuum from the charging dock once the battery reaches full. Leaving a V11 docked continuously feeds a low-level trickle current that accelerates cell degradation faster than regular use cycles do.

Motor cutting out under heavy carpet load on the V11

The V11's BMS monitors current draw in real time. On thick carpet or rugs, the motor pulls significantly more current than on hard floors — especially in Max or Boost mode. If the filter is partially blocked, airflow restriction forces the motor to work harder, spiking current draw past the BMS overcurrent threshold. The BMS trips, cuts power briefly, then resets — which users feel as a sudden stop-and-restart during cleaning.

Suction dropping well before the battery indicator shows low

This happens when cell voltage sags under load faster than the LCD indicator updates. A degraded or deeply discharged cell can sit at a resting voltage that reads as "charged" but collapses the moment the motor draws current. On the V11, voltage sag under load shows up as reduced suction power rather than a shutdown. If resting voltage reads above 22V but suction feels weak within the first few minutes of use, the cell is no longer holding its working voltage under load — replace it.