Pharos PTL525P Replacement Battery 3.7V 1100mAh

Pharos PTL525P / Traveler GPS 525 Series — 3.7V Li-ion Replacement Battery (PZX45)

This 3.7V, 1100mAh Li-ion battery replaces OEM part PZX45 in the Pharos PTL525P, Traveler GPS 525, 525e, and 525t pocket PC and PDA handhelds. It fits the original battery bay and connects to the same BMS interface as the factory cell. Use the capacity figure from the product data: 1100mAh / 4.07Wh.

• PTL525P and Traveler GPS 525 series compatibility: These models share a common 3.7V single-cell architecture, the same PZX45 form factor, and the same BMS handshake protocol — that's why one replacement cell covers the full lineup without modification.
• Bench tested on actual hardware: We cycled this cell on the PTL525P platform and confirmed the BMS accepted charge, reported state-of-charge correctly to the OS, and held voltage above the low-battery cutoff threshold through a full discharge cycle.
• Pre-swap data sync — do this before pulling the battery: The PTL525P holds open application state and unsaved contacts in SRAM powered directly by the main battery. Remove the cell without syncing first and that data is gone. Connect to ActiveSync or your host PC and confirm sync is complete before the swap.

Why the PTL525P won't boot after a new battery is installed

A fresh replacement cell ships partially discharged — typically between 30% and 50% charge. The PTL525P boot sequence draws a short high-current spike that a low-voltage cell can't sustain, so the device either shows a blank screen or cycles off immediately. This isn't a fault with the battery or the device. Charge the new cell for at least two hours before attempting the first boot. Voltage needs to be above 3.6V before the boot sequence will complete reliably.

GPS lock taking longer than usual after a battery replacement

The Traveler GPS 525 series stores almanac and ephemeris data in battery-backed memory. When the main cell is fully removed, that data clears — the GPS receiver loses its last known satellite positions and has to perform a cold start. A cold start acquisition can take several minutes outdoors with a clear sky view. Once the unit has locked and run a full session, it writes fresh almanac data back to memory and subsequent lock times return to normal.