Samsung Galaxy A51 5G EB-BA516ABY Replacement Battery 3.85V 4400mAh

Samsung Galaxy A51 5G — 3.85V Li-Polymer Replacement Battery (EB-BA516ABY)

This is a 3.85V, 4400mAh Li-Polymer replacement battery for the Samsung Galaxy A51 5G. It fits SM-A516D, SC-54A, SM-A516J, and the broader SM-A516 series. The OEM part number is EB-BA516ABY, also cross-referenced as GH82-22889A.

• SM-A516 series compatibility: Every SM-A516 variant shares the same battery bay dimensions, connector pin-out, and BMS handshake protocol. That is why one cell covers a wide range of regional and carrier-specific A51 5G models without modification.
• Bench tested on actual hardware: We ran this cell on an SM-A516 unit and confirmed the BMS completed its handshake, fast-charge negotiation initialised correctly on the second cycle, and the fuel gauge IC tracked state-of-charge without erratic jumps after one full discharge-charge calibration pass.
• First-cycle fast-charge protocol: After installing this cell, disable Samsung Adaptive Fast Charging for the first complete discharge-charge cycle. The fuel gauge IC needs to map the new cell's discharge curve at a steady low current before the charge IC begins pushing higher amperage. Skipping this step can leave the coulomb counter reading 5–10% off for weeks.

Sudden shutdown at 20–30% on the A51 5G after a cell swap

This is a voltage cliff issue, not a capacity problem. The A51 5G draws a sharp current spike when the 5G modem and display are active simultaneously. A new cell with an uncalibrated fuel gauge IC can report 25% remaining while the actual terminal voltage drops below the BMS cutoff threshold under that load. The phone shuts down to protect the cell even though the percentage looks safe. One full discharge-to-shutdown followed by an uninterrupted charge to 100% resets the coulomb counter and moves the cutoff trigger to the correct voltage point, typically around 3.40V under load.

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

On first power-up, the A51 5G's charge IC defaults to trickle current until it confirms the new cell's BMS is responding correctly. Until that handshake completes, the phone will not negotiate the fast-charge protocol with the adapter — it charges slowly and may not show the "Fast charging" indicator. This is not a fault with the adapter or the cable. Charge to 100% on standard current once, then disconnect and reconnect the fast charger. The charge IC re-initiates protocol negotiation and fast charging resumes at the correct rate.