Pax IS486 E500 Compatible Battery 3.7V 2600mAh

Pax E500 — 3.7V Li-ion Replacement Battery (IS486)

This is a 3.7V, 2600mAh Li-ion battery for the Pax E500 portable payment terminal. It replaces part number IS486 when the original cell degrades and can no longer hold a working charge. The E500 is a countertop and handheld POS device used for card transactions in retail and hospitality environments.

• E500 connector and BMS match: The IS486 form factor uses a specific multi-pin connector that carries both power and communication lines to the E500 mainboard. A mismatched cell either fails the BMS handshake or triggers a low-voltage warning at first boot regardless of state of charge.
• Bench tested on actual hardware: We ran this cell through a full boot sequence on an E500 unit, pushed through the PCI initialisation, and monitored BMS communication. The charge IC accepted the cell and the fuel gauge reported correctly after one complete charge cycle.
• First transaction cycle before live deployment: After fitting this battery, complete one full transaction cycle before putting the terminal into a live payment queue. The E500 maps battery capacity during normal operation and needs at least one complete power cycle to calibrate the charge indicator correctly.

Pax E500 rebooting mid-transaction after a battery swap

When the receipt printer fires, the E500 draws a short high-current burst that can exceed what a partially initialised BMS will allow. On a freshly installed cell, the BMS overcurrent threshold is still at its factory default — tighter than normal operating headroom. This causes the terminal to cut power mid-print or mid-tap, which looks like a software crash but is a hardware protection trip. Run two or three test transactions before live use to allow the BMS to settle into its normal operating window.

E500 not powering on after sitting unused in a drawer

Li-ion cells self-discharge at roughly 2–3% per month. If the E500 has been in storage long enough, the cell voltage can drop below 3.0V — the point where most BMS circuits lock the output to prevent damage. The terminal will not respond to the power button at all, which is commonly misread as a dead unit. Connect the original charger and leave it for at least 30 minutes before attempting to power on; the charge IC needs to trickle the cell back above the 3.0V recovery threshold before normal charging resumes.