About this replacement
Samsung Galaxy A80 — 3.85V Li-Polymer Replacement Battery (EB-BA905ABU)
This is a 3.85V, 3700mAh Li-Polymer battery for the Samsung Galaxy A80 smartphone. It fits the SM-A805F/DS, SM-A805N, and other Galaxy A80 2019 variants. It replaces OEM part numbers EB-BA905ABU, GH82-20346A, and EB-BA905ABE.
- Galaxy A80 rotating camera platform: The SM-A805 series shares a single battery footprint across all regional SKUs. The connector pinout, BMS handshake voltage, and physical dimensions — 59.86 × 60.12 × 5.74mm — are identical across the entire A80 lineup, so one cell covers all variants.
- Bench tested on actual hardware: We ran this cell on an SM-A805F unit and cycled it through a full discharge and charge sequence. The BMS accepted the cell without triggering overvoltage or temperature fault flags, and fast charge negotiation completed normally by the second cycle.
- Fuel gauge recalibration on first use: After installation, disable fast charging and run one complete discharge-charge cycle at standard speed. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging starts pushing current into an uncalibrated cell.
Why the Galaxy A80 reports wrong battery percentage after a cell swap
The Galaxy A80 uses a coulomb counter IC that builds its fuel gauge model against the original cell's charge curve over hundreds of cycles. When you swap the cell, the IC is still referencing the old degraded curve. The result is a percentage reading that drifts — often reading 30% when the cell is nearly flat. One full discharge-to-shutdown followed by a complete charge cycle forces the IC to reset its reference baseline against the new cell.
Sudden shutdown at 20–30% on the replacement cell
This happens when the modem radio or the AMOLED panel draws a current spike that the cell cannot sustain at lower state-of-charge, causing voltage to sag below the BMS cutoff threshold even though the fuel gauge still shows charge remaining. It is more common in the first few cycles on a fresh cell before the gauge IC recalibrates. After one full reference cycle, the cutoff threshold aligns more accurately to actual cell voltage under load. If shutdowns persist past three cycles, check that the battery connector is fully seated — a partially connected cell raises contact resistance and amplifies voltage sag.