About this replacement
Acer Spin 5 SP515-51GN-84KQ — 15.28V Li-Polymer Replacement Battery (AC14B7K)
This is a 15.28V, 3250mAh (49.66Wh) Li-Polymer battery for the Acer Spin 5 SP515-51GN-84KQ convertible laptop. It also fits the Swift 3 SF314-56 and Aspire 7 A715-71G series, among others. OEM part numbers AC14B7K, KT.00407.003, and KT.00407.006 all reference this same cell configuration.
- Spin 5, Swift 3, and Aspire 7 compatibility: These models share a common 15.28V four-cell Li-Polymer architecture, the same physical connector pinout, and an identical BMS handshake protocol — which is why one cell covers all three lines without hardware modification.
- Bench tested on actual hardware: We ran this cell through charge, discharge, and BMS communication checks. The BMS correctly reported state-of-charge over the SMBus and did not trigger false low-voltage cutoff at any point in the cycle.
- Post-install calibration on the Spin 5: After fitting this cell, run one full discharge down to hibernate cutoff, then charge uninterrupted to 100%. This resets the BIOS battery learn cycle and clears the inaccurate health warning that appears in Acer Care Center after every cell swap.
BIOS reporting battery health as poor after installing a new cell
Acer's BIOS and Care Center app read health data from EEPROM registers that store cycle count and capacity history from the original cell. A new cell ships with different EEPROM values, so the system flags it as degraded even though the cell is physically fine. Running a full discharge-to-hibernate followed by an uninterrupted charge to 100% lets the fuel gauge IC re-anchor its calibration points. After two to three full cycles, the health indicator typically corrects itself without any firmware intervention.
Laptop shuts down at 20–30% shown on the fuel gauge
This happens when the fuel gauge IC has not yet recalibrated against the new cell's actual voltage curve. The old calibration data causes the gauge to misread remaining capacity, and the system hits the low-voltage protection threshold well before the display reaches 0%. The fix is a slow, full discharge under moderate load — screen on, Wi-Fi active — until the laptop hibernates on its own. After that, charge fully to 100% without interruption, and the gauge IC resets its endpoints to the new cell's real 15.28V full-charge and cutoff floor.