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Pax A920 Pro Compatible Battery 3.7V 5150mAh YW-008

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Fits Pax A920 Pro payment terminal, replaces OEM battery part number YW-008.
3.7V, 5150mAh Li-Polymer cell delivers full charge capacity for multi-transaction merchant shifts.
Connector seats into terminal battery slot with alignment tab; locking mechanism requires firm seating.
We bench-tested this cell in A920 Pro hardware; BMS accepted charge handshake on first cycle.
After installation, run one complete transaction cycle before live deployment—the terminal calibrates charge indicator during normal operation.
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🔹 Getting Started

Charge your new battery fully before you use it for the first time. Over the next few charge cycles, run your device down to around 20% before you recharge—this helps the battery perform its best. After that, charge whenever you need to.

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Avoid letting your battery completely drain or staying plugged in constantly. Both extremes wear it out faster. Store the battery in a cool, dry place when you're not using it, since heat damages batteries quickly.

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🔹 We use these names, brands, or model numbers only for identification and compatibility purposes.

Voltage

3.7V

Amp

5150mAh

Pax A920 Pro — 3.7V Li-Polymer Replacement Battery (YW-008)

This 3.7V, 5150mAh Li-Polymer battery is a direct replacement for the Pax A920 Pro mobile payment terminal. It fits the A920 Pro and restores power capacity to this merchant-facing POS device. Part number YW-008 matches the original cell format at 70 x 60 x 10mm.

  • A920 Pro platform fit: The A920 Pro uses a single Li-Polymer cell with a specific connector and BMS handshake. This cell matches that voltage rail and connector layout so the terminal's charge controller recognises it without throwing a battery fault code.
  • Bench tested on actual hardware: We cycled this cell through the A920 Pro's charge IC and confirmed the BMS accepted the handshake on first boot. The charge controller entered normal CC/CV charging without tripping a protection flag.
  • First deployment tip for POS terminals: After installation, complete one full transaction cycle before deploying in a live environment. The A920 Pro maps battery capacity during normal operation and requires at least one complete power cycle to calibrate the charge indicator correctly.

Payment terminal rebooting mid-transaction after battery swap

The A920 Pro's receipt printer and wireless radio draw current simultaneously during a transaction. On a new cell, the BMS protection threshold can trip during this combined load spike before the cell has completed its first full charge cycle. The BMS reads the surge as an overcurrent event and cuts output to protect the cell. Run the terminal through one complete charge before putting it into a live transaction environment — that cycle allows the BMS to set its overcurrent baseline against the actual cell capacity.

Terminal not completing PCI boot sequence after sitting unused

If an A920 Pro sits unused for an extended period, the cell can self-discharge below the BMS recovery threshold — typically under 2.5V per cell. At that voltage, the BMS locks out discharge and the terminal won't complete its PCI boot sequence or show any sign of life. Connect the terminal to its original charger and leave it undisturbed for at least 30 minutes to allow the charge IC to trickle-charge the cell back above the recovery threshold. Once the cell reaches approximately 3.0V, the BMS unlocks and normal charging resumes.

Compatible Models

A920 Pro

Replaces Part Numbers

YW-008

Technical Specifications

Voltage3.7V
Amp Hours5150mAh
Capacity5150mAh
Rate19.06Wh
Net Weight88g /3.10 oz
Gross Weight113g /3.99 oz
Approximate Weight113g /3.99 oz
Dimension 70.00 x 60.00 x 10.00mm

Product Highlights

  • Brand: Pax
  • Manufacturer: CS
  • Series: Standard
  • Color: Black
  • Product Type: Li-Polymer
  • Battery Type: Li-Polymer
  • Warranty: 12 Months
  • Bulk Orders: sales@batteryweb.com

Frequently Asked Questions

The charge indicator on my A920 Pro is stuck at 99% and won't reach 100% — is the battery faulty?

This is normal behaviour on a new Li-Polymer cell. The A920 Pro's charge IC enters a top-off mode near full capacity, where current tapers down significantly and the indicator can hold at 99% for an extended period. The cell is charging correctly — the charge controller is applying a low finishing current to avoid overcharging. Leave the terminal on charge until the indicator moves to 100% and the charging LED changes state.

My A920 Pro gets noticeably warm during a busy transaction period — is the battery causing this?

The heat comes from the combined draw of the display, wireless radio, and receipt printer running at the same time, not from a battery fault. Li-Polymer cells generate heat under sustained load, and the A920 Pro's form factor concentrates that heat in a small enclosure. As long as the terminal remains functional and doesn't shut down, this is within normal operating range. If the terminal does shut down from heat, move it to a cooler surface and avoid stacking it under other equipment during peak hours.

After I swapped the battery, the A920 Pro powers on but the battery percentage jumps erratically — what's wrong?

The terminal's fuel gauge IC lost its calibration reference when the old battery was removed. The A920 Pro recalibrates state-of-charge by tracking a full discharge and charge cycle against the new cell's actual capacity. Run the terminal down to automatic low-battery shutdown, then charge it uninterrupted to 100%. After that single calibration cycle, the percentage reading stabilises.

Payment & Security

Payment methods

  • American Express
  • Apple Pay
  • Diners Club
  • Discover
  • Google Pay
  • Mastercard
  • PayPal
  • Shop Pay
  • Visa

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