About this replacement
Sunmi V1S / V2 / P1 / W6900 — 3.7V Li-ion Replacement Battery (SMBP001)
This is a 3.7V, 6700mAh Li-ion replacement battery for the Sunmi V1S, V2, P1, and W6900 mobile payment terminals. It matches OEM part numbers SMBP001 and SM-INR18650M26-1S2P. If your terminal dies mid-shift or can no longer hold charge through a full trading day, this is the direct replacement.
- V1S, V2, P1, and W6900 compatibility: These four terminals share the same single-cell 3.7V rail, the same physical cavity dimensions, and the same BMS handshake protocol. One battery fits all four without any firmware or connector workaround.
- Bench tested on actual hardware: We cycled this battery through full charge-discharge runs and simulated combined printer, display, and wireless draw. The BMS held cutoff thresholds correctly and passed charge-state reporting back to the terminal OS without errors.
- Post-swap calibration for payment terminals: After installation, complete one full transaction cycle before deploying in a live environment. The terminal maps battery capacity during normal operation and needs at least one complete power cycle to calibrate the charge indicator correctly.
Terminal rebooting mid-transaction after battery swap
The V1S receipt printer draws a short, sharp current spike every time it fires. On a new battery that hasn't completed a calibration cycle, the BMS can read this spike as an overcurrent event and trip the protection circuit, killing power instantly. This looks like a random reboot but it's a BMS overcurrent response, not a software crash. Run the terminal through several complete transaction cycles — including receipts — before live deployment. Once the BMS has logged normal operating current draws, the trips stop.
Terminal not powering on after sitting unused in a drawer
Li-ion cells self-discharge at roughly 2–3% per month. A terminal left unused for several months can drop the cell voltage below the BMS recovery threshold — typically around 2.5V — and the BMS locks out to prevent damage. The terminal won't respond to the power button. Connect the original Sunmi charger and leave it for 30–45 minutes without pressing anything; the charge IC will trickle-charge the cell back above the recovery threshold before switching to normal charge mode. Once the charge indicator appears on screen, the BMS has re-initialised.