About this replacement
Rowenta RH845901 / RH845301 Series — 12V Ni-MH Replacement Battery (RS-RH5157)
This is a 12V, 2000mAh Ni-MH replacement battery for the Rowenta RH845901 and RH845301 cordless stick vacuums. It slots into the same battery compartment as the original RS-RH5157 cell and powers the motor and suction system directly. When the original battery can no longer hold a full charge, this cell restores the vacuum to full working condition without replacing the entire unit.
- RH845901 and RH845301 platform fit: These models share the same 12V battery bay, connector orientation, and motor voltage rail — that is why one cell covers all four variants including the RH8453019A0 and RH8459019A0 production codes. The BMS in each model accepts the same charge termination signal from a Ni-MH cell at this capacity.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the RH845901 motor circuit. The BMS accepted charge termination cleanly, and the motor drew consistent current from the cell across both hard floor and carpet suction loads with no mid-cycle dropout.
- Dock charging discipline for this vacuum: Remove the vacuum from the charging dock as soon as the charge light clears. The RH845901 charger does not stop pushing current the moment the cell is full — sustained trickle charge on Ni-MH cells in this format compresses capacity noticeably within a few months.
Suction dropping before the battery indicator reaches low
On the RH845901, the motor pulls significantly more current when the filter is partially blocked or the floor nozzle is restricted. The battery voltage sags under that elevated draw, and the motor loses power well before the charge indicator triggers its low-battery alert. The indicator reads cell voltage at rest, not under load — so a restricted airpath causes a false reading. Clean the filter and check the nozzle pathway first; if suction stabilises, the battery is not the cause.
Motor cuts out mid-clean and then recovers after a few seconds
This is a BMS overcurrent trip, not a dead battery. When suction is sustained against a blockage or a heavily loaded carpet, current draw spikes past the BMS protection threshold and the cell disconnects to prevent damage. The BMS resets automatically after a short cooldown, which is why the vacuum restarts without intervention. Clear any blockage, check the filter is clean, and confirm airflow is unrestricted — the trip threshold on this cell is calibrated for normal motor draw, not sustained restricted-airpath load.