About this replacement
Lenovo Yoga C740-15IML — 11.52V Li-Polymer Replacement Battery (5B10T83739)
This is an 11.52V, 5050mAh (58.18Wh) Li-Polymer battery for the Lenovo Yoga C740 2-in-1 convertible laptop series. It fits the Yoga C740, Yoga C740-15IML, and Yoga C740-15 models. OEM part numbers covered include 5B10T83739, 5B10T83740, L18M3PFA, and L18D3PF2.
- Yoga C740 series fit: The C740, C740-15IML, and C740-15 all share the same 11.52V three-cell Li-Polymer configuration, physical connector, and BMS handshake protocol. Swapping between these variants requires no adapter or wiring change.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a C740-15IML. The BMS negotiated correctly with the EC firmware — no error flags, no charge interruption, and the fuel gauge IC registered capacity within expected tolerance after two calibration cycles.
- Post-install calibration on the C740: After fitting, discharge the laptop fully until it hibernates at low battery cutoff, then charge uninterrupted to 100% without using the machine. This forces the BIOS battery learn cycle to reset against the new cell and clears the false "poor health" warning that appears in Lenovo Vantage after every cell swap.
BIOS reporting battery health as poor after replacement on the C740
The Yoga C740's embedded controller stores charge history and health metrics tied to the original cell's EEPROM data. When a new cell is installed, that stored data no longer matches the new chemistry, so the BIOS flags it as degraded. This is not a fault with the replacement — it is a calibration mismatch. Running one full discharge-to-hibernate followed by an uninterrupted full charge resets the learn cycle. After two to three cycles, Lenovo Vantage should report health accurately.
Laptop shutting down at 20–30% charge shown on screen
This happens when the fuel gauge IC still holds calibration data from the old, degraded cell. The percentage shown on screen no longer maps to real cell voltage, so the laptop hits voltage cliff before the OS expects it. The EC triggers an immediate shutdown to protect the board — it is not a fault in the new cell. Discharge fully to hibernate cutoff, then charge to 100% uninterrupted twice in a row to recalibrate the fuel gauge against the new cell's actual voltage curve. After that, the displayed percentage should track correctly down to approximately 3.2V per cell before cutoff.