Elson EL370 Replacement Battery 3.7V 550mAh Li-ion

Elson EL370 / Mobistel kat / Mobilfunk — 3.7V Li-ion Replacement Battery

This is a 3.7V, 550mAh (2.04Wh) Li-ion cell for the Elson EL370, Mobistel kat, and Mobilfunk smartphones. It fits the same battery bay and connector as the original cell. Use this when the factory battery no longer holds a charge or fails to power the phone.

• EL370, Mobistel kat, and Mobilfunk compatibility: These three models share the same 3.7V battery bay, connector pin-out, and BMS communication protocol — one cell covers all three without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the EL370 platform. The BMS accepted the cell, charge termination triggered correctly at 4.2V, and protection circuits responded normally to load and cutoff conditions.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging if supported and run one complete discharge-charge cycle before normal use. This gives the fuel gauge IC time to map the new cell's discharge curve — without it, the percentage counter may read against the old cell's profile and report inaccurate state of charge.

Sudden shutdown at 20–30% on the EL370 after a cell swap

This is a voltage cliff issue, not a capacity problem. The fuel gauge IC still holds calibration data from the old degraded cell, so it trusts a state-of-charge reading that no longer matches the new cell's actual voltage curve. Under modem load or screen-on draw, the cell voltage drops sharply below the 3.4V cutoff threshold before the gauge registers critical. The phone shuts off to protect the cell — not because the replacement battery is faulty. One full discharge to automatic shutdown followed by an uninterrupted charge to 100% resets the coulomb counter and fixes this.

Phone feels warm near the battery compartment during the first few charges

A new Li-ion cell typically has higher internal impedance than a well-cycled one. The charge IC pushes current into that higher impedance, and some of the energy converts to heat rather than stored charge. This is normal for the first two or three cycles and reduces as the cell breaks in. If the phone stays warm beyond cycle three, or the back panel gets hot to touch, check that no third-party fast-charge adapter is overriding the charge current limit — use the original charger and keep input at 5V/1A for the first full cycle.