About this replacement
Shark V2940C Series — 6V Ni-MH Replacement Battery (XB2940)
This is a 6V, 3000mAh Ni-MH replacement battery for the Shark V2940C cordless vacuum. It fits the V2940C, V2940CFS, V1940, and V2940 models. When the original pack no longer holds a charge, this swap restores the vacuum to working condition without replacing the whole unit.
- V2940 series compatibility: The V2940C, V2940CFS, V1940, and V2940 all run the same 6V power rail and use the same XB2940 pack format. The connector, cell count, and BMS voltage thresholds are identical across these models, so one pack covers all four.
- Bench tested on actual hardware: We cycled this pack through full charge and discharge runs on the V2940 platform. The BMS held cutoff at the correct low-voltage threshold and accepted charge from the stock Shark charger without fault flags or charge rejection.
- Dock charging habit on Shark stick vacs: Do not leave this vacuum sitting on the charging dock between uses. Shark cordless vacs on continuous dock charge develop capacity fade faster than those charged only when depleted. Charge the pack fully, then remove it from the dock.
Suction dropping before the battery indicator reaches low on the V2940C
This happens when a partially blocked filter forces the motor to draw more current than rated. The cell voltage sags under that elevated load and the motor loses speed — even though the battery indicator still reads mid-range. The indicator measures resting voltage, not load voltage, so it lags behind what the motor actually sees. Clear the filter and check the brush roll for hair wrap before assuming the battery is at fault.
Motor cuts out mid-run and then recovers after a few seconds
This is a BMS overcurrent trip, not a dead battery. When sustained suction restriction — a blocked filter, a stuck brush roll, or a sealed floor surface — drives current above the BMS trip threshold, the pack shuts the output to protect the cells. The BMS resets automatically after a short thermal recovery window, which is why the vacuum starts again unprompted. Fix the restriction first; if cut-outs continue on an unblocked vacuum with a new filter, measure pack voltage under load — it should hold above 5.4V during normal operation.