About this replacement
Toshiba E800 / E805 / E808 / E800w — 3.7V Li-ion Replacement Battery (PA3330P-1BAS)
This is a 3.7V Li-ion replacement battery rated at 3800mAh (14.06Wh) for the Toshiba E800 series Pocket PC. It fits the E800, E805, E808, and E800w handhelds. The original PA3330P-1BAS cells degrade after several years, and this unit restores power to devices still running Windows Mobile for scheduling, contacts, and field applications.
- E800 / E805 / E808 / E800w compatibility: All four models share the same battery bay geometry, connector pinout, and BMS communication protocol. The PA3330P-1BAS part number covers the entire E800 series — no modification or adapter required.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the E800 platform. The BMS handshake completed correctly, charge acceptance registered in Windows Mobile's power applet, and the protection circuit tripped at the expected low-voltage threshold.
- Sync before you swap: The E800 stores open application state and unsaved data in SRAM powered directly by the main battery. Pull the battery without syncing first and that data is gone. Run ActiveSync or Windows Mobile Device Center and confirm a full sync completes before removing the old cell.
Why the E800 won't boot after a fresh battery is installed
The E800 boot sequence requires a minimum voltage at the board before it will attempt to load Windows Mobile. A new cell shipped in storage state may sit below that threshold — typically around 3.0V — and the device will show nothing when you press the power button. This is not a dead battery or a faulty unit. Connect the charger and let the cell reach at least 3.4V before attempting to power on. The boot screen should appear within the first charge cycle.
E800 showing incorrect battery percentage after replacement
Windows Mobile reads the battery gauge through the BMS fuel gauge circuit, which calibrates itself against charge and discharge history. A fresh cell has no history, so the percentage readout is unreliable for the first one to two cycles. Run the device down until it triggers the low-battery warning, then charge it uninterrupted to 100%. After two full cycles the gauge should track accurately. If the percentage still jumps erratically after that, check that the battery contacts on the device are clean and making firm contact — oxidised pins cause intermittent BMS reads.