About this replacement
Shark SV726 — 12V Ni-MH Replacement Battery (X8902)
This is a 12V, 2000mAh Ni-MH replacement battery for the Shark SV726 cordless stick vacuum. It fits the SV726 directly, using OEM part number X8902. The battery slot, connector orientation, and BMS handshake match the original unit.
- SV726 platform fit: The SV726 runs a 12V Ni-MH cell architecture with a specific connector and BMS communication line. This battery matches that voltage rail and connector pinout so the vacuum's motor controller reads the pack correctly and does not throw a fault on startup.
- Bench tested on actual hardware: We cycled this pack through the SV726's charge and discharge circuit. The BMS handled the Ni-MH charge termination cleanly — delta-V cutoff triggered at the correct point, and the pack delivered stable voltage across the motor load without sagging into the low-voltage cutoff early.
- Dock charging on the SV726: Do not leave the SV726 sitting on its charging dock permanently. Ni-MH cells on continuous trickle charge develop capacity fade faster than cells charged only when depleted. Charge to full, then remove from the dock.
Suction dropping before the battery indicator reaches low
The SV726 motor draws more current when the filter is partially blocked — restricted airflow forces the motor to work harder to maintain suction. That higher current draw pulls pack voltage down faster than normal, triggering the motor controller's low-voltage protection before the indicator registers low. The vacuum then feels like it's losing suction, but the real cause is filter restriction forcing the battery into early cutoff. Clean or replace the filter first, then test — you'll likely see the voltage hold above 10.5V under load rather than sagging below it.
Motor cutting out mid-clean and then recovering after a few seconds
This is a BMS overcurrent trip, not a dead battery. When the SV726 runs over heavy carpet or pulls against a blockage, current spikes sharply. The BMS reads that spike as a fault and cuts the output to protect the cell. After a few seconds the BMS resets and allows current flow again. Check the brush roll for tangled debris and confirm the filter is clean — both cause sustained high draw that keeps tripping the protection circuit. If the cutout stops after clearing the blockage, the battery is functioning correctly.