About this replacement
Dyson DC31 Animal / DC34 / DC35 Series — 22.8V Li-ion Replacement Battery (965557-03)
This is a 22.8V, 2500mAh (57Wh) lithium-ion battery for the Dyson DC31 Animal, DC34, DC34 Animal, DC35, and related cordless vacuum models. It replaces OEM part numbers 965557-03, 917083-01, 202932-02, and Type-B packs. Fit the replacement when the original no longer holds charge or the vacuum powers off before the battery indicator reaches low.
- DC31 / DC34 / DC35 platform compatibility: These models share the same 22.8V battery rail, connector pinout, and BMS handshake protocol — which is why a single cell covers all three lines. Swapping across models in this family does not require any adapter or firmware change.
- Bench tested on actual hardware: We ran this cell on a DC35 under a sustained restricted-filter load. The BMS held the correct cutoff threshold and did not trip false overcurrent during the motor-start surge. Voltage recovery after load removal matched OEM spec.
- Dock charging habit on DC31 and DC35: Do not leave the vacuum on the charging dock continuously. These models draw a low trickle through the dock even after the cell is full. Charge to full, then remove — this single habit slows capacity fade measurably over the battery's life cycle.
Cordless vacuum losing suction before the battery indicator reaches low
This happens when a partially blocked filter forces the motor to draw more current than rated. Voltage sags under that sustained overcurrent load, and the BMS interprets the sag as a depleted cell — killing power well before the indicator suggests it should. The fix is not the battery. Clean or replace the pre-motor and post-motor filters first, then retest. If suction loss continues on a clean filter, check the cell resting voltage — a healthy pack at partial charge should sit above 20V at rest.
Motor cuts out mid-clean, then recovers after a few seconds
This is a BMS overcurrent trip, not a dead battery. When airflow is restricted — by a blockage, a clogged filter, or a sealed floor nozzle — the motor draws a current spike the BMS flags as unsafe and shuts the output rail. After a few seconds the BMS resets and power returns. Clear the blockage, check the filter, and run the vacuum again. If the cut-out repeats on unrestricted airflow with a clean filter, measure cell voltage under load — a cell dropping below 18V during normal use indicates genuine cell degradation.