AEG Rapido 4.8V Ni-MH Replacement Battery 2000mAh

AEG Rapido ErgoRapido Series — 4.8V Ni-MH Replacement Battery (405 52 51-53/4)

This is a 4.8V, 2000mAh Ni-MH replacement battery for the AEG Rapido and ErgoRapido cordless handheld vacuum range. It fits the AG5104WDB and AG5104WD models alongside other units in the same series. The cell pack matches the original voltage rail and connector orientation of the factory battery.

• Rapido and ErgoRapido series fit: These models share the same 4.8V Ni-MH cell configuration, connector footprint, and charge termination protocol — one battery covers the range without modification.
• Bench tested on actual hardware: We ran this pack through charge and discharge cycles on a Rapido unit. The BMS accepted charge termination correctly and the motor drew current within the rated window under normal suction load.
• Dock charging on the Rapido: Do not leave the vacuum sitting on the dock between uses. The Rapido's charger does not cut off automatically when the cell is full. Continuous trickle charge degrades Ni-MH cells faster than any other single factor — charge when depleted, then remove.

Suction dropping before the battery indicator shows low

Ni-MH cells in the Rapido don't fail all at once — they sag under load first. When the motor draws current against a restricted airflow path, the pack voltage dips below the motor's operating threshold before the charge indicator registers a problem. The indicator reads resting voltage, not loaded voltage. Clean the filter before attributing the symptom to the battery — a blocked filter forces the motor to work harder, pulling more current and triggering sag earlier in the charge cycle.

Motor cuts out mid-clean and then recovers after a short pause

This is a BMS overcurrent trip, not a dead battery. When suction is sustained against a partial blockage — hair wrap on the brush bar or a clogged filter — current draw spikes above the pack's rated threshold and the protection circuit opens. The motor stops, the pack rests, voltage recovers, and the vacuum starts again. Clear the blockage first. If the trip repeats on a clean machine with a new battery, check that the charger is reaching a full 4.8V terminal voltage before each session.