About this replacement
Shark V3700UK Type 1 — 3.7V Li-ion Replacement Battery (XBAT3700)
This is a 3.7V 3400mAh Li-ion replacement battery for the Shark Cordless Rechargeable Hard Floor Sweeper V3700UK and V3700 Type 1. It fits directly into the V3700UK Type 1 sweeper and restores power to the brush motor and drive system. Capacity matches the original at 3400mAh (12.58Wh).
- V3700 and V3700UK Type 1 compatibility: Both the V3700 and V3700UK Type 1 variants share the same 3.7V single-cell architecture, connector pinout, and BMS handshake protocol — this battery covers both without modification.
- Bench tested on actual hardware: We ran this cell through the V3700UK charging circuit and confirmed the BMS accepted the full charge cycle, balanced correctly at 4.2V, and tripped the protection circuit as expected on a simulated overcurrent draw.
- Dock charging behaviour on this sweeper: The V3700UK has no automatic dock cutoff — leave it seated on the charger after a full charge and the cell absorbs a continuous trickle current. Charge to full, then remove from the dock and store the sweeper unplugged.
Suction dropping before the battery indicator reaches low on the V3700UK
The V3700UK motor draws harder when airflow is restricted — a partially blocked filter or clogged brush roll forces the cell to supply current above its rated continuous output. The BMS reads this as a stress condition and throttles output voltage before the charge indicator registers as low. The sweeper loses suction noticeably while the light still shows adequate charge. Clean or replace the filter first; if the problem persists with a clean filter, the original cell has degraded below usable capacity and needs replacing.
Motor cuts out mid-use then recovers after a short pause
This is a BMS overcurrent trip, not a mechanical fault. On the V3700UK, sustained restricted airflow — a jammed brush roll or heavily loaded filter — causes instantaneous current spikes the protection circuit treats as a short-circuit event, cutting power to the motor. Releasing the trigger and waiting roughly 10–15 seconds allows the BMS to reset and restore output. If cut-outs happen repeatedly on a clear filter with a new cell, check the brush roll for hair wrap binding the motor shaft directly.