About this replacement
Lenovo IdeaPad L340 17 Gaming — 11.52V Li-Polymer Replacement Battery (L18C3PF1)
This is an 11.52V, 3850mAh (44.35Wh) lithium-polymer replacement battery for the Lenovo IdeaPad L340 series. It fits the L340 17 Gaming, L340-17IRH, L340 15 Gaming, and L340-15IRH, among others. OEM part numbers L18C3PF1, 5B10T04976, and SB10W67243 all cross-reference to this cell.
- L340 series compatibility: The L340 15 and L340 17 Gaming variants share the same 11.52V three-cell battery rail, connector pinout, and BMS handshake protocol — one cell fits both chassis sizes without modification.
- Bench tested on actual hardware: We ran this cell on an L340-17IRH and confirmed the BMS negotiated correctly, charge acceptance reached full capacity, and no fault codes appeared in Lenovo Vantage during the charge cycle.
- First-cycle recalibration on the L340: After installation, run the laptop down to hibernate-cutoff under normal load — gaming or sustained CPU use works well — then charge uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell and clears the inaccurate health warning that appears after every cell swap on this platform.
Why the L340 Gaming BIOS reports poor battery health after a cell swap
The L340's BIOS stores learned capacity data from the previous cell in EEPROM. When a new cell goes in, the stored figures don't match the new chemistry, and the firmware flags a health warning. This is not a fault with the replacement cell. Running one full discharge-to-hibernate followed by an uninterrupted charge to 100% rewrites the learned values and clears the warning. Lenovo Vantage will show accurate health status once the learn cycle completes.
L340 shutting down at 20–30% charge shown on screen
This symptom means the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The percentage shown is based on old learned data, so the laptop hits the real low-voltage cutoff before the displayed number reaches zero. The fix is two to three full discharge-and-charge cycles under genuine load — use the GPU and display at full brightness to stress the cell. After calibration, the gauge tracks accurately and the BMS cutoff aligns with the displayed percentage near 5V per cell.