About this replacement
Sony PRS-300 Series — 3.7V Li-Polymer Replacement Battery (LIS1382(S))
This is a 3.7V, 680mAh lithium-polymer replacement battery for the Sony PRS-300 e-reader series. It fits the PRS-300, PRS-300SC, PRS-300RC, and PRS-300BC. It replaces OEM part LIS1382(S) and cross-references 1-756-769-31, 9702A50844, and 9924A60515.
- PRS-300 series fit: The SC, RC, and BC variants of the PRS-300 share the same battery bay dimensions, voltage rail, and connector pinout as the base model. One cell covers all four variants without modification.
- Bench tested on actual hardware: We cycled this cell through the PRS-300's charge circuit and confirmed the BMS accepted charge without flagging an incompatible cell. Charge termination and cutoff voltage behaved as expected at the device's 4.2V ceiling.
- Post-swap charge cycle: After installing this cell, charge via USB before powering on. The PRS-300 firmware reads battery state-of-charge at boot. If the cell voltage is below the boot threshold from storage, the device will not initialise — connect USB first and allow at least a partial charge before pressing the power button.
Why the PRS-300 shows incorrect battery percentage after a cell swap
The PRS-300 stores a charge profile in firmware tied to the previous cell's discharge curve. After swapping to a new cell, the displayed percentage will often read inaccurately for the first few cycles. This is not a fault with the replacement cell — it is the firmware recalibrating its internal model. Run two or three full charge-to-discharge cycles and the percentage display will stabilise. No hardware reset is required.
PRS-300 not powering on after battery replacement
Replacement cells ship at partial storage voltage, typically around 3.6–3.8V. The PRS-300 requires a minimum boot voltage closer to 3.7V to initialise the e-ink controller — cells at the low end of storage voltage will not clear that threshold. Connect the device to a USB power source immediately after installation and wait at least 10 minutes before attempting to power on. If the charge LED activates, the cell is seated correctly and the device will boot once voltage climbs above the boot threshold.