About this replacement
Lenovo Yoga C640 13 / 13IML — 7.7V Li-Polymer Replacement Battery (SB10W67395)
This is a 7.7V, 7550mAh (58.14Wh) lithium-polymer battery for the Lenovo Yoga C640 13 and Yoga C640 13IML convertible notebooks. It replaces OEM part numbers SB10W67395, L19C4PD1, L19D4PD1, 5B10U65274, and 5B10U65275. Correct fit covers both the standard Yoga C640 13 and the Intel Core 13IML variant.
- Yoga C640 13 and 13IML compatibility: Both models share the same 7.7V battery rail, connector pinout, and BMS handshake protocol. The 13IML uses an Intel Core MX chipset but draws from the same battery architecture — one cell fits both.
- Bench tested on actual hardware: We ran this cell on a Yoga C640 13IML and confirmed the BMS handshake completed on first boot. BIOS recognised the battery within one full charge cycle and charge regulation switched from CC to CV at the correct voltage threshold.
- Post-swap learn cycle on the C640: After fitting this cell, run the laptop down to hibernate cutoff, 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 after fitting a new cell on the C640
The Yoga C640 stores battery health data in EEPROM on the original cell. When a new cell goes in, the BIOS compares current readings against cached EEPROM values from the old battery and flags a health warning. This is not a fault with the replacement cell — it is a calibration mismatch. Run one full discharge to hibernate, then charge to 100% without interruption. After one or two full cycles, the BIOS recalibrates and the health warning clears.
Yoga C640 shutting down at 20–30% charge shown on screen
This symptom usually means the fuel gauge IC has not yet calibrated against the new cell's actual chemistry. The OS reads a state-of-charge percentage based on learned data from the old cell, so the numbers diverge from real voltage under CPU and display load. At full processor and screen brightness, voltage can drop sharply past the BMS cutoff point before the displayed percentage catches up. Run two full discharge-to-hibernate and charge-to-100% cycles — the fuel gauge IC recalibrates against real cell voltage and the early shutdowns stop.