About this replacement
Lenovo ThinkPad T480s — 11.58V Li-Polymer Replacement Battery (01AV478)
This 11.58V, 4600mAh (53.27Wh) lithium-polymer battery fits the Lenovo ThinkPad T480s ultrabook. It replaces the original internal cell when capacity has degraded or the battery has failed outright. Compatible OEM part numbers include 01AV478, 01AV479, L17L3P71, L17M3P71, SB10K97620, and several related variants.
- T480s internal battery platform: The T480s uses a fixed internal 3-cell Li-Polymer pack running a single 11.58V rail. All T480s variants — including the 20L7 and 20L8 chassis codes — share this same connector pinout and BMS handshake protocol, which is why one cell works across more than 170 sub-models.
- Bench tested on actual hardware: We ran this cell through the T480s charge controller and confirmed the BMS accepted the pack without fault codes. Charge current ramped correctly through CC and CV phases, and the fuel gauge IC registered cell capacity within normal bounds after two full cycles.
- First-cycle calibration on T480s: After installing, discharge the laptop normally until it hibernates at low battery, then charge uninterrupted to 100% without interruption. This forces the BIOS battery learn cycle to reset against the new cell and clears the inaccurate health warning that appears after every internal cell swap.
BIOS reporting battery health as poor immediately after replacement
The T480s BIOS stores learned capacity data from the previous cell in non-volatile memory. When a new cell goes in, that cached data no longer matches actual cell behaviour, so the BIOS flags health as poor or unknown. This is not a fault with the replacement cell — it is a data mismatch. Running one complete discharge-to-hibernate followed by a full uninterrupted charge resets the learn cycle. After two or three cycles the health indicator typically returns to normal.
T480s shutting down at 20–30% charge shown on screen
This happens when the fuel gauge IC is still calibrated to the old cell's voltage curve. The new cell hits a voltage cliff under combined CPU and display load at a state of charge the gauge still reads as 20–30%. The laptop interprets this voltage drop as a critical low and shuts down. Discharge fully to hibernate-cutoff and recharge to 100% twice — after these calibration cycles the gauge maps correctly to the new cell's curve and the premature shutdowns stop.