Samsung Galaxy A16 5G Replacement Battery EB-BA166ABY 4850mAh

Samsung Galaxy A16 5G — 3.88V Li-Polymer Replacement Battery (EB-BA166ABY)

This is a 3.88V, 4850mAh lithium-polymer cell built to replace the original EB-BA166ABY battery in the Samsung Galaxy A16 5G. It fits SM-A166B, SM-A166B/DS, SM-A166E, and additional SM-A166 variants. Capacity matches the factory spec at 18.82Wh.

• SM-A166 variant compatibility: All SM-A166 models share the same battery bay dimensions, connector pinout, and BMS handshake protocol — the same cell covers the full variant range without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on an SM-A166B unit. The BMS accepted the cell without error flags, and the charge IC stepped through trickle, CC, and CV phases cleanly at both standard and fast-charge rates.
• First-cycle fast-charge protocol: On first use after installation, disable fast charging for one complete discharge-charge cycle. The fuel gauge IC is still calibrated to the old cell's discharge curve — running fast charge before recalibration pushes high current into an uncalibrated cell and can cause early charge termination on subsequent cycles.

Sudden shutdown at 20–30% on the replacement cell

After a cell swap, the Galaxy A16 5G's fuel gauge IC still holds the discharge curve from the original degraded battery. When the phone hits 20–30% reported charge, the new cell's actual voltage may already be at a point where modem radio bursts or screen backlight spikes pull the cell below the BMS cutoff threshold. The BMS trips, and the phone shuts off — not because the cell is empty, but because the gauge is reading the wrong curve. One full discharge-to-shutdown followed by an uninterrupted charge to 100% lets the coulomb counter reset against the new cell. After that cycle, shutdowns at false percentages stop.

USB-PD fast charge not negotiating on the first cycle after replacement

On the first charge cycle after fitting the EB-BA166ABY replacement, some units stay in standard 5W charging even when plugged into a fast-charge adapter. The new cell's BMS presents a higher impedance than the worn original, which can cause the charge IC to fall back to a lower current profile while it maps the cell's internal resistance. This is not an adapter or cable fault. Let the first full charge complete at the standard rate — on the second cycle, the charge IC renegotiates with the correct current ceiling and fast charging resumes at its full rate.