About this replacement
HP iPAQ 300 Series — 3.7V Li-ion Replacement Battery (HSTNH-S12B)
This is a 3.7V, 1700mAh Li-ion battery for the HP iPAQ 300, 310, 312, and 314 handheld PDAs. It replaces OEM part numbers HSTNH-S12B, HSTNH-F15C, 430128-002, and HSTNH-L05-xx. The cell fits directly into the original battery bay with no modification required.
- iPAQ 300-series compatibility: The 300, 310, 312, and 314 all run the same 3.7V battery bay and share identical connector pinout and BMS handshake requirements. One cell fits the full range without adapter or firmware change.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on the iPAQ platform and confirmed the BMS accepted charge normally, reported state-of-charge accurately to the OS, and held stable voltage under both idle and active wireless loads.
- RAM data protection before swap: Perform a full ActiveSync or Windows Mobile Device Center sync to the host computer before removing the battery. The iPAQ 300 series stores open application state and unsaved data in volatile SRAM powered directly by the main cell — cutting power without syncing first will erase that data.
Why the iPAQ 300 loses contacts and calendar data after a battery swap
The iPAQ 300 uses SRAM for working memory, and SRAM requires continuous power to retain data. When the battery is removed, even briefly, the RAM loses its contents entirely. This is not a fault with the new battery — it is how the platform works. Contacts, calendar entries, and installed applications stored only in RAM will be gone when the device reboots. Sync all data to a host PC or use a storage card before swapping the battery.
iPAQ 300 stuck on the boot screen after fitting a new battery
If the replacement cell arrives partially discharged, the iPAQ may not complete its boot sequence — the device needs sufficient voltage to initialise the radio and load the OS from flash. A cell reading below roughly 3.5V at the terminals may stall the boot. Connect the iPAQ to the original charger and leave it for at least 30 minutes before attempting to power on. Once the charge LED confirms current is flowing, try booting again.