About this replacement
Acer Swift 3 SF315-52G Series — 15.2V Li-ion Replacement Battery (AC17B8K)
This is a 15.2V, 3150mAh (47.88Wh) Li-ion battery for the Acer Swift 3 SF315-52G-54DA, SF315-52G-89HT, SF315-52-58FQ, SF315-52G-550X, and over 175 other Swift 3 SF315-52 variants. It slots into the same bay and uses the same four-cell configuration as the original AC17B8K pack. It also cross-references as KT.0040G.012.
- SF315-52 and SF315-52G shared platform: Both the non-G and G-suffix models share the same 15.2V four-cell rail, identical connector pinout, and the same BMS handshake protocol — so one part number covers the full range without modification.
- Bench tested on actual hardware: We ran this cell on an SF315-52G chassis and confirmed the BMS completed the charge handshake correctly, hit full charge termination at 16.8V, and reported accurate state-of-charge data to the ACPI layer throughout the cycle.
- Post-installation calibration on the Swift 3: After fitting, run one full discharge to hibernate-cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the false health warnings that appear in Acer Care Center after every cell swap.
BIOS reporting poor battery health immediately after fitting the AC17B8K
The Swift 3 BIOS reads health data from the EEPROM embedded in the original pack. When a new cell is installed, that EEPROM data is gone — the BIOS flags the pack as degraded because it has no charge history to reference. This is not a fault with the replacement cell. Running a full discharge-to-hibernate followed by a full uninterrupted charge forces the fuel gauge IC to write a new baseline. After one or two full cycles, the BIOS health indicator returns to normal.
Swift 3 shutting down abruptly at 20–30% charge shown on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual discharge curve. The percentage shown is based on old data, so the reported 25% may represent a real voltage that the cell can no longer sustain under the combined load of the CPU and display backlight. The cell hits its low-voltage cutoff — typically around 12.0V under load — before the OS gets a shutdown warning. The fix is to complete two full calibration cycles: discharge to hibernate, charge to 100%, repeat once more.