About this replacement
Vizio CT15-A Series — 7.4V Li-Polymer Replacement Battery (SQU-1108)
This is a 7.4V, 6950mAh (51.43Wh) lithium-polymer replacement battery for the Vizio CT15-A0, CT15-A1, CT15-A2, and CT15-A5 notebook computers. It matches the original SQU-1108 and AHA42236000 part numbers. If your Vizio CT15 no longer holds a charge or shuts down unexpectedly, this cell fits the same bay and connector as the stock unit.
- CT15-A series compatibility: The CT15-A0 through CT15-A5 all share the same 7.4V two-cell battery bay, connector pinout, and BMS handshake protocol. That is why one replacement cell covers all four variants without modification.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on CT15 hardware. The BMS handshake completed correctly, the fuel gauge IC recognised the new cell, and charge termination triggered at the correct voltage ceiling.
- First-cycle reset after installation: After fitting the new cell, run the laptop on battery until it hibernates at low charge, then charge uninterrupted to 100%. This forces the BIOS to complete a learn cycle against the new cell's actual capacity and clears the inaccurate health warning that appears after every cell swap.
BIOS reporting battery health as poor immediately after replacement
The CT15 BIOS reads battery health data from EEPROM stored on the old cell. When a new cell is fitted, that EEPROM data is gone, and the BIOS flags the battery as unknown or degraded before any calibration has run. This is not a fault with the replacement cell — it is a data mismatch. Run one full discharge-to-hibernate cycle followed by an uninterrupted charge to 100%, and the BIOS will rewrite its battery learn data against the new cell. After one or two cycles, the health warning clears and the reported capacity stabilises.
CT15 shutting down at 20–30% charge shown on screen
This happens when the fuel gauge IC has not yet calibrated against the new cell's actual voltage curve. The gauge shows 25% remaining, but the cell voltage is already dropping below the BMS cutoff threshold under full CPU and display load — so the laptop cuts power before the gauge reaches zero. The fix is calibration: discharge the laptop to hibernate cutoff under normal use, then charge fully without interruption. After two full cycles, the gauge maps correctly to the new cell and shutdowns stop occurring above the true 10–12% floor, which sits around 7.0V at the battery terminals.