About this replacement
Lenovo Legion Y720-15IKB — 15.36V Li-Polymer Replacement Battery (5B10M33724)
This is a 15.36V, 3800mAh (58.37Wh) Li-Polymer battery for the Lenovo Legion Y720-15IKB gaming laptop, covering variants 80VR and 81CQ along with regional models including 80VR00A6GE, 80VR002WGE, and 80VR007VAU. It replaces OEM part numbers 5B10M33724 and L16M4PB0. If your original cell no longer holds charge or the system reports degraded health, this is the direct swap.
- Y720-15IKB variant coverage: All 80VR and 81CQ board revisions share the same 15.36V four-cell architecture, connector pinout, and BMS handshake protocol — that is why one part number covers 20-plus regional SKUs without any electrical difference between them.
- Bench tested on actual hardware: We cycled this cell on a Y720 mainboard and confirmed the BMS negotiated correctly, charge current stepped through the expected constant-current and constant-voltage phases, and the protection circuit triggered at the correct low-voltage cutoff under a CPU-plus-GPU load spike.
- Post-install calibration on the Y720: After fitting this battery, run one full discharge down to hibernate cutoff, then charge uninterrupted to 100% without using the laptop. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears after every cell swap on this platform.
BIOS reporting battery health as poor immediately after replacement
The Y720 BIOS reads health data from EEPROM embedded in the battery pack. When a new cell arrives, that EEPROM carries factory baseline values that do not match the laptop's accumulated cycle history — the BIOS flags the mismatch as degraded health. This is a data reconciliation issue, not a fault with the new cell. One full discharge-to-hibernate followed by an uninterrupted charge to 100% forces the BIOS learn cycle to rewrite its reference table against the actual new cell. After two to three cycles the health readout normalises.
Legion Y720 shutting down at 20–30% charge shown
Under combined CPU turbo and discrete GPU load, the Y720 pulls high instantaneous current. If the cell voltage sags below roughly 14.0V during that spike, the BMS trips a protective cutoff before the fuel gauge reaches zero — the OS registers this as a sudden shutdown at 20–30% remaining. On an aged original cell this is a sign the cell can no longer sustain voltage under load. On a new replacement it typically means the fuel gauge IC has not yet calibrated against the new cell's discharge curve. Run two full discharge and recharge cycles and the shutdown threshold will shift to the correct level.