About this replacement
Palm M550 / Tungsten T Series — 3.7V Li-ion Replacement Battery (IA1TA16A0)
This is a 3.7V 850mAh Li-ion battery for the Palm M550 and Tungsten T1, T2, and T3 handheld PDAs. It replaces OEM part IA1TA16A0 and several cross-reference numbers including IA1W721H2, IA1T923A0, and GA1W918A2. The cell fits the same battery bay and connector across all listed models.
- M550 and Tungsten T1–T3 shared battery platform: These models use the same 3.7V single-cell Li-ion pack with a matching footprint and connector pinout. The BMS handshake is consistent across the series, so one cell fits all without any firmware conflict.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a Tungsten T3 unit. The BMS accepted the cell without fault codes, and charge termination triggered correctly at 4.2V.
- RAM data preservation before swap: Perform a full HotSync to your desktop before removing the battery. Palm PDAs store active application data and open files in SRAM powered directly by the main battery — removing the cell without syncing will wipe that data permanently.
Why the Palm M550 loses all data after a battery swap
The M550 uses SRAM for active storage, and that memory requires continuous power to retain its contents. Unlike flash-based storage, SRAM has no data persistence once voltage drops to zero. The moment the battery is removed and the backup capacitor drains — usually within seconds — the RAM clears entirely. Always run a HotSync before pulling the battery to push everything to the desktop.
Palm Tungsten not booting after new battery installed
If the Tungsten shows a blank screen or loops on the Palm logo after a battery swap, the cell voltage is likely below the minimum boot threshold. New Li-ion cells sometimes ship at storage charge around 3.6V, which is close to the BMS cutoff for boot initialisation. Plug the device into its charger for at least 30 minutes before attempting to power on. Once the cell reaches approximately 3.8V, the boot sequence completes normally.