Orange Vegas 3.7V Li-ion Replacement Battery 650mAh

Orange Vegas — 3.7V Li-ion Replacement Battery (Li3706T42P3h413457)

This is a 3.7V, 650mAh Li-ion replacement battery for the Orange Vegas smartphone. It replaces part number Li3706T42P3h413457 and fits directly into the Vegas housing. Install it when the original cell no longer holds a usable charge.

• Orange Vegas fit: The Vegas uses a slim fixed-footprint cell at 40.60 x 34.00 x 5.60mm. This replacement matches that footprint exactly. The connector pinout and BMS communication lines align with the Vegas charge IC — no adapter or modification needed.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the Vegas platform. The BMS handed off charge termination cleanly at 4.2V, and the protection circuit tripped correctly at the low-voltage cutoff threshold — no unexpected shutdowns during discharge.
• Fuel gauge recalibration on first use: After fitting this cell, disable fast charging for the first complete discharge-charge cycle. The Vegas fuel gauge IC was calibrated to the old cell's discharge curve. One full cycle at standard current lets it map the new cell before high-current charging pushes into an uncalibrated state.

Sudden shutdown at 20–30% on the replacement cell

The Orange Vegas fuel gauge IC reads state-of-charge from a stored discharge curve — not live cell voltage alone. A new cell has a different voltage-versus-capacity profile than the worn cell the IC was calibrated against. At around 3.55–3.60V, the new cell still has usable capacity, but the IC thinks it's at 20–30% and the modem or screen load causes a brief voltage sag below the shutdown threshold. One full discharge-charge cycle at standard current forces the coulomb counter to re-anchor to the new cell's actual curve and clears this behaviour.

Phone warm near the battery compartment on the first few charges

A new Li-ion cell has higher internal impedance than a partially aged one. The Vegas charge IC drives current into that higher-impedance cell, and the extra resistive loss exits as heat. This is most noticeable during the first two or three charges and settles as the cell conditions. If the device feels hot — not just warm — during charging, remove it from any case and charge on a flat surface until the first few cycles are done. By the third full charge, impedance drops and the warmth reduces noticeably.