Kyocera DuraForce Ultra 5G PCGF30 Replacement Battery 3.85V

Kyocera DuraForce Ultra 5G — 3.85V Li-ion Replacement Battery (PCGF30)

This is a 3.85V, 4500mAh Li-ion replacement battery for the Kyocera DuraForce Ultra 5G, DuraForce Ultra 5G UW, and E7110. It fits the original battery bay and uses the same connector and BMS handshake as the factory cell. Install it when the original battery no longer holds a usable charge or fails to power the device.

• DuraForce Ultra 5G, UW, and E7110 fit: All three models share the same battery bay dimensions, voltage rail, and PCGF30 connector pinout. The BMS on each device communicates the same handshake, so one cell covers the full model family without modification.
• Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the E7110. The BMS accepted the new cell on the first connection, held charge cutoff at 4.35V, and triggered low-voltage protection at the correct threshold without tripping early shutdown.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current fast charging pushes current into an uncalibrated cell — preventing false percentage readings from the first charge onward.

Sudden shutdown at 20–30% on the replacement cell

This happens because the fuel gauge IC is still calibrated to the old cell's voltage curve. When the new cell's voltage drops under 5G modem or screen load, it hits a cliff the gauge wasn't expecting — the phone reads 25% but the cell voltage has already fallen below the safe cutoff. The fix is one full discharge-charge cycle with the phone in normal use and fast charging disabled. After that cycle, the coulomb counter recalibrates to the new cell and the shutdowns stop.

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

On the first charge after a cell swap, the charge IC may reject the USB-PD handshake and fall back to standard 5W charging. This is the BMS protecting an uncalibrated cell — it doesn't yet have a verified state-of-charge reading, so it limits input current until it does. Run one full standard charge cycle first. After that, plug into a USB-PD charger and the fast charge protocol will negotiate correctly at the rated current.