Evolveo StrongPhone WIFI Compatible Battery 3.7V 1700mAh

Evolveo StrongPhone WIFI — 3.7V Li-ion Replacement Battery (SGP-WIFI-BAT)

This is a 3.7V, 1700mAh Li-ion cell (6.29Wh) that replaces the original SGP-WIFI-BAT in the Evolveo StrongPhone WIFI. It fits the StrongPhone WIFI only — verify your model before ordering. Dimensions are 52.45 × 36.00 × 10.40mm; check these against your existing cell if the phone has seen any aftermarket work.

• StrongPhone WIFI fitment: The SGP-WIFI-BAT connector and cell footprint are specific to this rugged handset's battery bay. The BMS handshake on the StrongPhone WIFI uses a single-wire thermistor line — any cell missing that contact will prevent the charge IC from initiating a charge cycle.
• Bench tested on actual hardware: We cycled this cell through full charge and load discharge on the StrongPhone WIFI platform. The BMS accepted the cell without error flags, and the charge IC held the correct 4.2V termination voltage throughout.
• 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 its coulomb counter against the new cell's actual discharge curve before high-current charging begins on an uncalibrated cell.

Sudden shutdown at 20–30% on the StrongPhone WIFI after a cell swap

This is a voltage cliff issue, not a capacity problem. The modem radio and screen draw a combined surge load that the new cell cannot sustain at low state-of-charge until it has been cycled. The fuel gauge IC is still referencing the old cell's discharge curve, so the reported percentage doesn't match the actual cell voltage. Run two full discharge-charge cycles without fast charging and the shutdowns will stop once the coulomb counter re-anchors to the new curve.

Phone shows wrong battery percentage after fitting the replacement cell

The StrongPhone WIFI's fuel gauge IC stores the previous cell's discharge profile in memory. After a cell swap, that stored curve no longer matches the new cell, so percentage readings drift or jump. The fix is one full uninterrupted discharge to auto-off, followed by a full charge to 100% with the phone off or idle. After that cycle the fuel gauge re-anchors its zero and full reference points to the new cell, and percentage reporting stabilises.