About this replacement
SumUp 3G / 3G+ Printer — 3.7V Li-ion Replacement Battery (PS-GB-18650-026H)
This is a 3.7V, 3350mAh Li-ion replacement battery for the SumUp 3G Printer and 3G+ Printer. It replaces part number PS-GB-18650-026H and restores wireless operation for merchants processing card payments away from a fixed power source. Capacity figures are taken directly from product data at 12.4Wh.
- 3G and 3G+ Printer compatibility: Both models share the same battery bay dimensions, connector pinout, and BMS handshake protocol. The cell format is 18650, measuring 66.20 × 21.00 × 18.50mm. Swapping between the two variants requires no modification.
- Bench tested on actual hardware: We cycled this cell through the SumUp boot sequence, ran consecutive print jobs, and confirmed the BMS reported state-of-charge correctly across multiple charge events. No overcurrent trips were recorded during printer motor actuation.
- First transaction cycle after installation: Complete one full transaction — boot to receipt print — before deploying in a live environment. The terminal maps battery capacity during normal operation and requires at least one complete power cycle to calibrate the charge indicator accurately.
SumUp 3G Printer rebooting mid-transaction after battery swap
The printer motor draws a short current spike each time it fires. On a new cell that hasn't completed a full charge cycle, the BMS may read that spike as an overcurrent event and trip the protection circuit, cutting power mid-print. This presents as a sudden reboot or blank screen during an active sale. Running one full boot-to-receipt cycle before live use lets the BMS establish accurate load thresholds and stops false trips.
Terminal not powering on after sitting unused in storage
Li-ion cells self-discharge at roughly 2–3% per month. A device left in a drawer for several months can drop the cell below the BMS recovery threshold — typically around 2.5V — at which point the terminal will not power on at all. Connect the device to its original charger and leave it for at least 60 minutes before attempting to boot; this allows the charge IC to trickle the cell back above the recovery floor. If the terminal still won't respond after that hold period, check that the charger is delivering the correct 5V input.