About this replacement
Ulefone Power — 3.85V Li-Polymer Replacement Battery (3026LN6050M44V)
This 3.85V, 6050mAh Li-Polymer cell is a direct replacement for the Ulefone Power smartphone. It fits the original battery bay and connects to the same charge IC and fuel gauge circuit. Capacity is 6050mAh (23.29Wh), matching the factory specification for this handset.
- Ulefone Power platform fit: The Power series runs a high-capacity 3.85V cell architecture to support its large display and always-on LTE modem. This cell matches that voltage rail and connector pinout — the BMS handshake completes on first boot without any manual override.
- Bench tested on actual hardware: We cycled this cell through charge and load on the bench. The BMS held cutoff at the correct low-voltage threshold, charge termination triggered cleanly at full capacity, and the protection circuit tripped correctly on a simulated over-current event.
- Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This gives the fuel gauge IC a clean reference curve against the new cell before high-current charging pushes into an uncalibrated coulomb counter.
Sudden shutdown at 20–30% on the Ulefone Power after a cell swap
The Ulefone Power's modem and display draw a combined spike load that can expose voltage sag in a new cell before the fuel gauge has mapped its actual discharge curve. When the reported state of charge sits around 20–30%, the cell voltage under that combined load can drop below the BMS cutoff threshold — even though the displayed percentage suggests capacity remains. The phone interprets this as a fault and shuts down to protect the circuit. One full discharge-to-3.2V followed by a full charge cycle at standard rate usually eliminates this behaviour as the fuel gauge IC locks onto the real cell characteristics.
USB fast charge not activating on the first cycle after replacement
After fitting a new cell, the charge IC on the Ulefone Power sometimes refuses to negotiate fast charge on the first connection — defaulting to standard 5V input instead. This happens because the charge controller reads the new cell's impedance as out of range during its initial safety check. Run the phone through one full standard-rate charge from below 10% to 100%, then reconnect the charger. Fast charge negotiation typically resumes once the controller has recorded a valid baseline charge cycle against the new cell.