Easyfone Prime A1 Replacement Battery 3.7V 900mAh

Easyfone Prime A1 / A2 / A5 — 3.7V Li-ion Replacement Battery

This 3.7V, 900mAh Li-ion battery replaces the original cell in the Easyfone Prime A1, Prime A2, and Prime A5 mobile phones. The cell measures 53.00 × 34.00 × 4.30mm and slots directly into the same bay as the factory unit. If your phone shuts off unexpectedly or no longer holds a charge, this is the part that restores normal operation.

• Prime A1, A2, and A5 compatibility: All three models share the same battery footprint, voltage rail, and connector orientation. The BMS handshake on each device is identical, so one cell covers the full trio without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Prime A1 platform. The BMS accepted the cell without error flags, and the charge IC completed a full cycle without thermal cutoff or early termination.
• Fuel gauge recalibration on first use: After fitting this battery, run one full discharge down to automatic shutdown, then charge uninterrupted to 100% before use. This lets the fuel gauge IC map the new cell's discharge curve correctly — skipping this step is the main cause of erratic percentage readings after a cell swap.

Sudden shutdown at 20–30% on the Easyfone Prime A1

The Prime A1 draws a sharp current spike when the modem transmits or the screen backlights at full brightness. A degraded cell — or a freshly installed one the fuel gauge hasn't calibrated yet — cannot sustain voltage under that load. The BMS reads the voltage drop as a low-battery condition and cuts the circuit. This is not a fault with the replacement cell; it is the fuel gauge IC operating on stale calibration data from the old battery. One full discharge-charge cycle resets the coulomb counter and eliminates most sudden-shutdown events.

Phone won't power on after the battery sat in storage

Li-ion cells self-discharge over time. If this battery was stored for several months before installation, or if the phone was left unused with the battery inside, the cell voltage may have dropped below the BMS lockout threshold of approximately 2.5V. At that point the BMS opens the protection circuit and the phone shows no sign of life. Connect the phone to a wall charger — not a USB port — and leave it for 15–20 minutes without pressing any buttons. The charge IC will trickle current into the cell until the BMS re-engages, after which the phone will boot normally.