About this replacement
Samsung GT-S5830 / GT-S5660 Series — 3.7V Li-ion Replacement Battery (EB494358VU)
The EB494358VU is a 3.7V, 1000mAh Li-ion cell that powers the Samsung GT-S5830 (Galaxy Ace), GT-S5830T, Cooper, GT-S5660, and 17 additional variants. It replaces the original battery when the existing cell has degraded, swells, or no longer holds a usable charge. Physical dimensions are 57.50 × 42.50 × 4.80mm — verify these against your current cell before fitting.
- GT-S5830 / S5660 platform compatibility: These models share the same battery bay dimensions, connector pinout, and BMS communication protocol — a single cell covers all variants on the list. The protection circuit communicates charge state to Samsung's fuel gauge IC over the same two-wire interface used across the Ace platform.
- Bench tested on actual hardware: We ran this cell through a full charge-discharge cycle on a GT-S5830 unit. The BMS accepted charge handshake immediately, current tapered correctly at full charge, and the protection circuit tripped as expected under a short-circuit load test before resetting cleanly.
- Fuel gauge recalibration on first cycle: After fitting this cell, disable Samsung's adaptive fast charge and run one complete discharge down to automatic shutdown, then charge uninterrupted to 100%. This gives the fuel gauge IC a full sweep of the new cell's discharge curve before it starts interpolating percentage readings.
Why the GT-S5830 reports wrong battery percentage after a cell swap
Samsung's fuel gauge IC stores a discharge curve from the old cell in memory. When a new cell goes in, that stored curve no longer matches the actual voltage-to-capacity relationship of the replacement. The phone reads voltage, maps it against the old curve, and outputs a percentage that can be off by 15–25%. One full uninterrupted discharge-charge cycle rewrites the reference curve and brings percentage reporting back in line with actual capacity.
Sudden shutdown at 20–30% remaining on the replacement cell
This happens when the fuel gauge IC has not yet calibrated to the new cell and the reported percentage is running ahead of actual charge state. Under modem or screen load, the cell voltage drops below the BMS cutoff threshold — around 3.0V — while the OS still shows 20–30% remaining. The phone shuts down to protect the cell, not because of a fault. Run the full recalibration cycle described above; after one complete discharge-charge sweep the reported percentage will track actual voltage correctly and the shutdowns stop.