Rowenta RH845901 Cordless Vacuum Compatible Battery 12V 4000mAh

Rowenta RH845901 / RH845301 Series — 12V Ni-MH Replacement Battery (RS-RH5157)

This is a 12V, 4000mAh Ni-MH replacement battery for the Rowenta RH845901 and RH845301 cordless stick vacuum range. It uses OEM part number RS-RH5157 and fits both the RH8453019A0 and RH8459019A0 variants. Replace it when your vacuum's run time has dropped significantly or the unit no longer holds a charge.

• RH845301 and RH845901 platform fit: Both models share the same 12V battery bay, connector pinout, and BMS handshake protocol — one battery covers the full range. The RS-RH5157 cell pack matches the original voltage rail so the motor controller does not flag a voltage mismatch on startup.
• Bench tested on actual hardware: We ran this cell pack through full charge-discharge cycles on a Rowenta RH845901 unit. The BMS accepted the replacement without fault codes, and the motor reached operating speed without current-limiting intervention from the controller.
• Dock charging discipline for Ni-MH cells: Ni-MH chemistry is particularly vulnerable to trickle-charge damage from continuous dock charging. Once the indicator shows full, remove the vacuum from the dock. Leaving it docked permanently accelerates capacity fade in Ni-MH cells faster than in Li-ion equivalents.

Suction dropping before the battery indicator reaches low

This happens when the motor draws more current than the battery can sustain at its rated voltage. A partially clogged filter or blocked airway forces the motor to work harder, pulling the cell pack below its stable discharge voltage before the indicator registers low. The vacuum's power output drops noticeably as a result. Clean the filter and clear any blockage at the brush head first — if suction recovers immediately, the battery is not the fault.

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

This pattern points to a BMS overcurrent trip, not a dead cell. When sustained suction restriction forces the motor to draw above the BMS threshold, the protection circuit cuts power and resets after a cooldown period. It will repeat on the same carpet pass if the restriction is still present. Check and clean the filter — on the RH845901, the foam pre-filter sits behind the dust cup and blocks airflow when saturated with fine debris.