About this replacement
Acer Swift 5 SF514-53T / TravelMate X514 — 7.7V Li-Polymer Replacement Battery (AP16L5J)
This is a 7.7V, 4650mAh (35.81Wh) Li-Polymer battery replacing OEM part AP16L5J and KT00205002. It fits the Acer Swift 5 SF514-53T-58PJ, Swift 5 Pro SF514-52TP, TravelMate TMX514-51T, Spin 1 SP111-32N, and over 190 additional Acer thin-and-light models sharing the same voltage rail and connector layout. Install it when the original cell no longer holds a charge or the system refuses to run on battery alone.
- SF514 / X514 platform fit: These models share a 7.7V nominal rail, the same flat Li-Polymer form factor (221.58 × 94.94 × 4.00mm), and an identical 4-pin board connector with BMS communication lines. The BMS handshake on these Acer boards authenticates via EEPROM data embedded in the cell — a mismatch here is what triggers the "unknown battery" warning in BIOS on first boot.
- Bench tested on actual hardware: We ran this cell on an SF514-series board. The BMS accepted the handshake on first connection, charge current stepped down correctly through CC and CV phases, and the protection circuit tripped cleanly at the low-voltage cutoff threshold without requiring a manual reset.
- Post-install calibration on Acer ultrabooks: After fitting this battery, run the laptop down fully until it hibernates on low-voltage cutoff, then charge it uninterrupted to 100%. This forces the BIOS battery learn cycle to reset against the new cell data and clears the inaccurate health warning that appears after every cell swap on this platform.
BIOS reporting poor battery health immediately after fitting this cell
Acer's BIOS reads health status from EEPROM data stored in the original cell's BMS chip. When a new cell is installed, the BIOS compares current capacity readings against the old cell's stored baseline and flags a mismatch as degraded health. This is a calibration state, not a fault. Run one full discharge to hibernate cutoff, then a full uninterrupted charge to 100%. The BIOS learn cycle writes new baseline data at that point and the warning clears.
Swift 5 shutting down with 20–30% charge still showing on screen
The fuel gauge IC estimates remaining capacity based on voltage curves from the previous cell. After a swap, those curves no longer match the new cell's actual discharge profile. Under combined CPU and display load, voltage drops faster than the IC predicts, and the system hits the hardware protection cutoff before the gauge reaches zero. Two to three full discharge-and-charge cycles recalibrate the fuel gauge IC against the new cell. After calibration, the shutoff point should align with 0–5% shown on screen.