Pax S920 Compatible Battery 3.7V 2600mAh IS1112

Pax S920 — 3.7V Li-ion Replacement Battery (IS1112)

This is a 3.7V 2600mAh Li-ion battery for the Pax S920 portable payment terminal. It replaces OEM parts IS1112 and IS486. If your S920 is losing charge mid-shift or failing to hold power through a full trading day, this is the direct replacement.

• S920 platform fit: The S920 uses a specific BMS handshake tied to cell voltage and internal resistance. This battery matches that profile — the terminal's charge IC accepts the new cell and begins normal top-off charging without throwing a fault code.
• Bench tested on actual hardware: We cycled this battery through the S920's boot sequence, ran card transactions, and triggered the receipt printer. The BMS held stable across the full load cycle. No overcurrent trips or unexpected shutoffs were recorded.
• First deployment tip: After fitting the battery, complete one full transaction cycle before putting the terminal into live use. The S920 maps cell capacity during normal operation and needs at least one complete power cycle to calibrate the charge indicator correctly.

Receipt printer causing voltage sag on the S920 battery

The thermal printer in the S920 draws a sharp current spike each time it fires — more than the display or wireless radio pulls in normal operation. On a degraded or deeply discharged cell, that spike can push the battery voltage below the BMS protection threshold. The BMS interprets this as an unsafe condition and cuts output. A fresh cell at full charge handles the printer spike without dropping below 3.2V, which is the cutoff point the S920's BMS monitors during print events.

S920 not powering on after sitting unused in storage

Li-ion cells self-discharge over time. If the S920 sat in a drawer for several months, the battery may have dropped below 2.5V — the threshold where most BMS circuits lock out to prevent cell damage. The terminal will show nothing when you press the power button, which looks like a hardware fault but is usually just a depleted cell. Place the terminal on charge for at least 20 minutes before attempting to power on; the charge IC needs to see the cell recover above 2.9V before it will allow a boot.