HP iPAQ rx5000 Compatible Battery FA8277A 3.7V 1700mAh

HP iPAQ rx5000 / rx5700 Series — 3.7V Li-ion Replacement Battery (FA8277A)

This 3.7V, 1700mAh Li-ion cell replaces the original battery in the HP iPAQ rx5000, rx5700, rx5710, and rx5720 Pocket PC handhelds. It matches the OEM form factor at 62.60 × 55.60 × 5.73mm and connects directly to the device's existing battery contacts. Voltage and capacity match OEM spec: 3.7V, 1700mAh (6.29Wh).

• rx5000 and rx5700 platform fit: The rx5000, rx5710, and rx5720 share the same battery bay dimensions, connector pinout, and BMS handshake protocol — which is why a single cell covers the full series. The device's power management IC checks cell voltage and thermistor response on boot; this battery passes that check.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on an rx5700 unit. The BMS accepted the cell without fault flags, voltage held steady through the charge curve, and the protection circuit tripped correctly at low-voltage cutoff rather than letting the cell drop below safe threshold.
• RAM data sync before swap: The iPAQ rx5000 series stores open files, application state, and unsaved contacts in volatile SRAM powered directly by the main battery. Sync all data to your host PC via ActiveSync before removing the old cell. A full power loss — even brief — clears everything in RAM that has not been written to flash storage.

Why the iPAQ rx5000 won't boot after a battery swap

The rx5000's boot ROM checks for a minimum cell voltage before it will attempt to load the OS. A new battery shipped in storage state — typically around 3.0V to 3.2V — can fall below that threshold. The device either shows a blank screen or briefly flashes the HP logo before shutting off. Connect the charger and leave the unit on charge for at least 30 minutes before pressing the power button. Once the cell reaches roughly 3.5V, the boot sequence completes normally.

Battery life noticeably shorter when using Wi-Fi or Bluetooth on the rx5700

The rx5700 and rx5720 include an integrated wireless radio that pulls significantly more current than the CPU alone — the radio draw can be four to five times higher than standby. This voltage sag under wireless load makes the battery appear to deplete faster than the rated capacity suggests. If the device dims or resets during active wireless use, check that the cell is at full charge before starting a sync session. A resting voltage of 4.1V to 4.2V at the battery terminals confirms a full charge state and gives the radio its full current headroom.