Power and charging

PAX A920 / A920 Pro: battery will not charge, stops at 80%, or runs flat too fast

Why a PAX A920 or A920 Pro will not charge or power on, why an A920 Pro stops charging at 80% (Battery Management System), what the red taskbar and the battery-with-exclamation symbol mean, and when the battery needs replacing.

Applies to
PAX A920, A920 Pro
Last reviewed
Oct 26, 2026 by Abdul Rashid

Ask Allstar AI about this guide

Check first

  • Is this a brand-new unit? (The battery protective tab may still be fitted.)
  • Is it charging from the wall adapter, a PC USB port, or a charging base?
  • Does it stop at exactly 80%, or not charge at all?
  • How old is the battery? PAX says replace it every two years, or when runtime falls to half of new.
  • Is the battery swollen, deformed or warm?

Covers the common A920 and A920 Pro power complaints: will not charge, stops at 80%, red bar on screen, battery warning icon, short runtime.

Before you start

  • Use only the PAX adapter and cable. PAX warns other chargers can damage the battery.
  • Note the battery's age. PAX says replace it every two years, or when it only lasts half as long as new.
  • Never charge for more than 24 hours, and recharge a stored unit at least every six months.

Steps

  1. New unit: remove the battery, peel off the white protective tab until the POGO pins show, refit the battery, connect power. Expected: charging indicator appears.
  2. Swap to another PAX adapter and cable and use a wall outlet, not a PC USB port. Expected: if it now charges, the original adapter, cable or port was at fault.
  3. If the battery was flat, leave it on charge at least 30 minutes before powering on. Expected: it powers on once charged enough.
  4. A920 Pro stops at 80%: Settings > Battery > More Settings > Power Supply Work Mode. Desktop Mode stops at 80% and resumes at 70% (for units that live on a base or adapter); Mobile Mode charges to 100% and resumes at 90%; Auto-Adaption lets the terminal decide. Restart when prompted. Expected: it charges to the chosen mode's limit. The 80% stop in Desktop Mode is intended, to extend battery life.
  5. Red bar across the top: Settings > Battery > Battery Saver (A920) or Schedule Power Saving (A920 Pro) > Disabled. Expected: red bar gone.
  6. Battery icon with an exclamation mark: restart, confirm the PAX adapter and cable, check the charging port for lint or damage and clean gently with dry compressed air. Expected: symbol clears.
  7. Terminal frozen: remove and refit the battery, then power on. Expected: normal boot.

If that did not work

A swollen, deformed or hot battery means stop and contact Allstar; do not charge it. A battery that is two years old or lasts half as long as new is at end of life and should be replaced with a PAX battery through Allstar. A tamper message after a battery problem means the unit needs RMA. Do not attempt a factory reset for battery symptoms; it wipes the terminal and PAX gives no procedure for this case.

Sources

Stop and contact support if

  • Battery is swollen, deformed, damaged or hot: stop using the terminal and contact Allstar support. Do not charge it.
  • Runtime is about half of new, or the battery is two or more years old: the battery is at end of life. Contact Allstar for a replacement battery; do not fit a non-PAX battery.
  • Any 'Ped Tampered' or 'Terminal Be Attacked' message (PAX lists a damaged internal battery as one cause): stop, contact support for RMA.
  • PAX mentions a factory reset as a last resort for a misreported battery status, but gives no procedure and it erases all data. Do not factory reset; route to Allstar support.

Contact Allstar support (support@allstarterminals.com, 888-403-7066) with the model, serial number, battery age, how it is charged, and the exact message or symbol on screen.

Contact support about this

Notes

  • The Battery Management System (BMS) page says it was first implemented on some OS versions of the A920Pro, A77 and E600Mini. Whether a given A920 (non-Pro) has the Power Supply Work Mode setting is not stated; the A920 is only named for the Battery Saver red-bar setting.
  • The 80% page is a support email thread, not a formal document; PAX's own staff were still awaiting formal documentation when it was written.
  • Battery capacity differs by guide: the A920 quick setup guide lists 5250 mAh, the pax.us A920 Pro product page lists 5150 mAh.
  • Sources are PAX Technical Knowledge Base pages (PAX's Confluence site, linked from pax.us) plus the pax.us quick setup guides, which carry no version or date.

Sources

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