About this replacement
Samsung Galaxy A34 5G / A54 5G — 3.88V Li-Polymer Replacement Battery (EB-BA546ABY)
This is a 3.88V, 4900mAh Li-Polymer replacement battery for the Samsung Galaxy A34 5G and Galaxy A54 5G. It uses OEM part number EB-BA546ABY and fits the 2023 variants of both models. Drop it in when the original cell no longer holds a usable charge across a full day of calls, messaging, and app use.
- A34 5G and A54 5G shared platform: Both models run on Samsung's Exynos 1380 platform with the same battery bay dimensions and connector pinout. The BMS handshake and charge IC protocol are identical across these variants, which is why a single cell covers the full compatibility list.
- Bench tested on actual hardware: We ran this cell through full charge cycles on an A54 5G unit. The BMS accepted charge immediately, charge termination triggered correctly at 4.38V, and the fuel gauge IC showed a stable state-of-charge reading within one complete cycle.
- First-cycle fast charge protocol: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before the charge IC pushes high-current fast charge into an uncalibrated cell.
Sudden shutdown at 20–30% on the replacement cell
This happens because the fuel gauge IC is still using the discharge curve from the old, degraded cell. When the new cell's actual terminal voltage drops sharply under modem or display load, the OS reads it as a normal mid-range state of charge — until the cell can no longer sustain voltage and the phone cuts out. The fix is one full calibration cycle: drain to auto-shutdown, then charge uninterrupted to 100% with fast charging disabled. After that cycle, the coulomb counter resets to the new cell's curve and the shutdowns stop.
USB-PD fast charge not working on the first cycle after replacement
On the first charge after a cell swap, the charge IC sometimes falls back to standard 5W input instead of negotiating Samsung's Adaptive Fast Charge protocol. This is a BMS initialisation behaviour — the charge controller is conservative with an uncalibrated cell on the first cycle. Use the original Samsung charger and cable, not a third-party USB-PD adapter, for that first charge. Once the cell completes one full cycle and the BMS has a voltage baseline, fast charge negotiation resumes normally on subsequent cycles.