Black&Decker 520102 Cordless Vacuum Replacement Battery 2.4V

Black&Decker Classic HC 410E — 2.4V Ni-MH Replacement Battery (520102)

This is a 2.4V, 3000mAh Ni-MH replacement battery for the Black&Decker Classic HC 410E cordless handheld vacuum cleaner. It also fits the HC400, HC410, and HC410S models, along with 14 additional variants in the same Classic HC range. When the original cell can no longer hold a useful charge, this replacement restores the vacuum's ability to run the motor at full draw.

• Classic HC series compatibility: These models share the same 2.4V single-cell architecture, connector footprint, and motor draw profile. The BMS expects the same charge curve across all variants, so one cell covers the full range without modification.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the HC 410E platform. The BMS accepted the cell without fault codes, and the motor reached full operating voltage without tripping overcurrent protection under standard carpet load.
• Dock charging habit on the HC series: Do not leave the vacuum sitting on the charging dock between uses. These Ni-MH cells develop capacity fade significantly faster under continuous trickle charge. Charge to full, remove from the dock, and reconnect only when depleted.

Suction dropping before the battery indicator reaches low

On the Classic HC series, the motor voltage sag begins well before the cell is fully discharged — especially when the filter is partially blocked. A restricted airpath forces the motor to draw more current than rated, which pulls cell voltage down faster than normal discharge. The vacuum loses noticeable suction while the indicator still reads mid-charge. Clean or replace the filter first, then test the battery; a blocked filter mimics a failing cell almost exactly.

Motor cutting out mid-clean then recovering after a few seconds

This is a BMS overcurrent trip, not a dead battery. When suction is sustained against a blockage — hair wrap at the nozzle, a clogged filter, or carpet fibres packed at the intake — current draw spikes past the BMS threshold and the protection circuit cuts output. The motor restarts once the BMS resets, typically within three to five seconds. Clear the blockage, then retry; if the cutout continues on a clean machine, check cell voltage under load — it should hold above 2.0V during motor run.