About this replacement
Lenovo IdeaPad U350 Series — 14.8V Li-Polymer Replacement Battery (57Y6265)
This is a 14.8V, 3000mAh (44.4Wh) lithium-polymer replacement battery for the Lenovo IdeaPad U350 thin-and-light laptop. It fits the IdeaPad U350, U350 20028, U350 2963, and U350W. OEM cross-references include 57Y6265, 57Y6352, L09C4P01, and L09N8P01.
- U350 series fit: All four U350 variants share the same 14.8V battery rail, connector pinout, and BMS handshake protocol. The EEPROM data encoded in this cell matches what the IdeaPad U350's EC firmware expects to read on first contact.
- Bench tested on actual hardware: We ran this cell through a full charge-discharge cycle on a U350 unit. The BMS negotiated correctly, charge termination triggered at the rated 14.8V ceiling, and no fault codes were logged.
- First-cycle conditioning on the U350: After fitting, run the laptop down to hibernate-cutoff on battery only, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.
BIOS reporting poor battery health immediately after fitting a new cell
The IdeaPad U350's embedded controller reads health data from the EEPROM on the old cell and caches it. When a new cell goes in, that cached data doesn't automatically clear. The BIOS then compares the new cell's charge state against stale reference figures and flags it as degraded. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% forces the EC to rewrite its battery profile. After that cycle, the health indicator returns to normal.
Laptop shuts down at 20–30% charge shown on the gauge
This is a voltage cliff issue, not a fuel gauge error. Under combined CPU and display load, the cell voltage drops faster than the gauge can track, and the EC triggers a protective shutdown before the displayed percentage reaches zero. It typically happens when the fuel gauge IC hasn't yet calibrated against the new cell's actual discharge curve. Run two full discharge-to-hibernate cycles back-to-back, charging fully between each. After the second cycle, the gauge IC recalibrates and the shutdowns stop.