About this replacement
Sony PRS-350 / PRS-650 Series — 3.7V Li-Polymer Replacement Battery (LIS1459MHPC9SY6)
This is a 3.7V, 900mAh lithium-polymer cell for the Sony PRS-350, PRS-350SC, PRS-650, and PRS-650BC e-readers. It replaces OEM part LIS1459MHPC9SY6 (also listed as 1-853-016-11). The flat pouch cell fits the original battery bay with the same connector and contact layout as the factory unit.
- PRS-350 and PRS-650 platform compatibility: Both the PRS-350 and PRS-650 share the same 3.7V battery rail and connector pinout. The BMS on each model communicates fuel-gauge data over the same two-wire interface, so one cell works across the full range without any modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the PRS-350 and confirmed the BMS accepted the new cell, reported charge state correctly, and did not trigger a protection cutoff during the e-ink page-refresh load spikes.
- Post-swap firmware calibration: After installing the new cell, charge the reader through its micro-USB port until the indicator shows full before the first use. The PRS-350 firmware resets its battery percentage model at that point — skipping this step causes the charge display to jump erratically for the first several cycles.
Why the PRS-350 shows a low battery warning immediately after a new cell is fitted
Replacement cells ship in storage mode, typically between 3.0V and 3.3V. The PRS-350 firmware sets its low-battery warning threshold around 3.5V, so a cell fresh out of packaging reads as critically low before any charge is applied. This is not a fault with the cell or the board. Connect the reader to a USB power source straight after installation and leave it until the status light confirms a full charge. The firmware will then anchor its percentage display to the new cell's actual capacity.
PRS-350 not powering on after battery replacement
If the reader shows nothing on screen when you press the power button after swapping the cell, the new battery's voltage is likely below the minimum boot threshold the BMS requires to start the system. Connect a USB charger and wait at least ten minutes before pressing power again — the board needs enough charge to initialise before it will respond to the power button. If the screen remains blank after charging, press and hold the reset pinhole on the rear for five seconds while connected to USB, then attempt to power on again. The device should boot once cell voltage reaches approximately 3.6V.