Dyson V11 2020 Replacement Battery 25.2V 4000mAh 970938-01

Dyson V11 2020 Series — 25.2V Li-ion Replacement Battery (970938-01)

This is a 25.2V, 4000mAh (100.8Wh) lithium-ion battery for the Dyson V11 cordless vacuum range. It fits the V11 2020, V11 Absolute+, V11 Absolute Extra+, V11 Click-In, and over a dozen related V11 variants. OEM part numbers covered include 970938-01, 970425-01, and SV-series identifiers SV15, SV16, SV17, SV18, and SV22.

• V11 platform compatibility: The V11 range shares a common 25.2V battery rail, connector format, and BMS handshake protocol across all SV15–SV22 models. The battery communicates charge state data to the vacuum's LCD screen — cell count and BMS communication architecture must match, which they do across this entire variant group.
• Bench tested on actual hardware: We ran this cell on a V11 Absolute under motor load across all three suction modes. The BMS held voltage within spec through full discharge cycles, and the LCD screen reported accurate charge-state percentage throughout — no false low-battery cutoffs were triggered.
• Dock charging behaviour on V11 units: Do not leave the V11 sitting on the wall dock as a permanent storage position. Continuous dock contact keeps the BMS in a low-level trickle state that accelerates capacity fade. Charge to full, then remove the vacuum from the dock until the next use.

Suction dropping before the battery indicator reaches low

The V11 motor controller scales power output to available voltage. When cell capacity degrades or a filter restriction forces higher current draw, voltage sags under load before the battery gauge reflects it. The LCD may show two or three bars while suction has already weakened noticeably. A clean filter removes restriction and keeps current draw inside the BMS's preferred operating band — check and wash the filter before concluding the battery is at fault.

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

This is a BMS overcurrent trip, not a dead battery. When airflow is restricted — blocked filter, clogged brush bar, or heavy carpet pile — the motor draws sustained current above the BMS threshold and the protection circuit opens. The vacuum restarts after a short recovery window because the BMS resets once current demand drops. Clear the blockage completely, then check that resting pack voltage reads at least 25.2V before ruling out a cell issue.