About this replacement
SumUp 3G / 3G+ Printer — 3.7V Li-ion Replacement Battery (PS-GB-18650-026H)
This is a 3.7V, 2600mAh Li-ion replacement battery for the SumUp 3G Printer and 3G+ Printer. It replaces OEM part number PS-GB-18650-026H. The battery slots into the portable receipt printer that pairs with SumUp card payment terminals at the point of sale.
- 3G and 3G+ compatibility: Both models share the same battery bay dimensions, voltage rail, and BMS connector pinout. The PS-GB-18650-026H cell format — 66.20 × 21.00 × 18.50mm — fits both without modification.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on a SumUp 3G Printer. The BMS accepted the handshake cleanly, reported state-of-charge correctly, and held stable voltage under combined wireless and print-motor load.
- First transaction cycle after swap: Complete at least one full transaction — from power-on through receipt print — before deploying in a live environment. The printer maps battery capacity during normal operation and needs one complete power cycle to calibrate the charge indicator accurately.
Why the SumUp 3G Printer reboots mid-receipt on a new battery
The print motor draws a short current spike the moment it fires — this can trip the BMS overcurrent threshold on a cell that has not yet gone through a conditioning cycle. On a fresh replacement battery, the BMS protection circuit is set conservatively until it has logged a full charge-discharge pass. Running one complete print job from a fully charged state allows the BMS to log normal load behaviour and widen its trip window accordingly. After that first cycle, mid-print resets typically stop.
SumUp 3G Printer shows no power after sitting unused in storage
Li-ion cells self-discharge at roughly 1–2% per month. A printer left in a drawer for several months can drop the cell below the BMS recovery threshold — typically around 2.5V — causing the device to appear completely dead. Connecting the printer to its charger for 15–30 minutes at trickle rate will bring the cell back above the recovery voltage. Once voltage climbs past approximately 3.0V, the BMS re-initialises and normal charging resumes.