VeriFone CM5 Payment Terminal Compatible Battery BPK278-501 3.85V 3200mAh

VeriFone CM5 — 3.85V Li-Polymer Replacement Battery (BPK278-501)

This is a 3.85V, 3200mAh Li-Polymer battery for the VeriFone CM5 portable payment terminal. It replaces OEM part BPK278-501 directly. Use it when the original cell no longer holds charge through a normal transaction shift.

• CM5 platform fit: The CM5 uses a fixed 3.85V Li-Polymer cell with a dedicated BMS connector that handles communication between the battery and the terminal's charge IC. This replacement matches that voltage rail and connector pinout, so the terminal reads state-of-charge correctly rather than showing a fault or refusing to boot.
• Bench tested on actual hardware: We cycled this battery through charge and discharge on the CM5 platform and monitored BMS handshake acknowledgment. The charge IC accepted the cell without triggering a protection fault, and the terminal reported battery status normally through each cycle.
• First-use calibration on the CM5: After installing this battery, complete at least one full transaction cycle before putting the terminal into live service. The CM5 maps battery capacity during normal operation — running a complete power cycle lets the charge indicator calibrate and stops the terminal from displaying inaccurate charge levels.

Receipt printer causing a battery drain spike on the CM5

The CM5's thermal receipt printer draws a short but sharp current burst every time it fires. On a degraded original battery, that spike can trip the BMS overcurrent protection and drop the terminal unexpectedly. This replacement cell is rated to handle the combined draw of the display, wireless radio, and printer motor without the BMS cutting out. If the terminal still reboots during printing after a fresh install, check that the battery connector is fully seated — an intermittent contact amplifies the apparent load spike at the BMS.

CM5 not powering on after sitting unused in a drawer

Li-Polymer cells self-discharge slowly in storage. If the CM5 has sat unused for several weeks or months, the cell voltage may have dropped below the BMS recovery threshold — typically around 2.5V — and the terminal will not respond to the power button at all. Connect the terminal to its dock or USB-C power source and leave it for 15–20 minutes before attempting to power on. The charge IC performs a trickle pre-charge phase to bring the cell back above the recovery threshold before switching to normal charge mode. Once the charge indicator lights up on the terminal screen, the battery has crossed that threshold and the device will boot normally.