Wiko Sunny 2 Compatible Battery 3.7V 1300mAh 2510

Wiko Sunny 2 / V2510 — 3.7V Li-ion Replacement Battery (2510)

This is a 3.7V Li-ion cell rated at 1300mAh (4.81Wh), built to fit the Wiko Sunny 2 and V2510 smartphones. It slots into the same bay as the original cell and connects via the factory connector. Voltage and physical dimensions match OEM spec: 52.40 × 51.10 × 4.70mm.

• Sunny 2 and V2510 compatibility: Both models share the same battery bay geometry, connector pinout, and 3.7V nominal voltage rail. The BMS handshake on each is identical, so one cell covers both without modification.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on the Sunny 2 platform. The BMS accepted charge without fault flags, and cutoff triggered correctly at the low-voltage threshold — no spurious protection trips observed.
• Fuel gauge recalibration after swap: On first use after installing this cell, run one complete discharge down to auto-shutoff, then charge to 100% without interruption. This gives the fuel gauge IC a clean reference curve for the new cell and prevents erratic percentage readings in daily use.

Why the Sunny 2 reports wrong battery percentage after a cell swap

The Sunny 2 uses a coulomb-counting fuel gauge IC that builds its charge model against the original cell's discharge curve. When a new cell goes in, the IC's stored reference no longer matches actual cell behaviour. The result is percentage readings that jump, stall, or report full when the cell still has capacity left — or vice versa. One full discharge-to-shutoff followed by an uninterrupted charge to 100% forces the IC to rewrite its reference map against the new cell.

Sudden shutdown at 20–30% on the replacement cell

This happens when the cell voltage drops sharply under load — typically when the modem fires at full power during a call or the screen brightness spikes. The fuel gauge reports 25% remaining, but the cell can't sustain voltage under that current draw, so the phone cuts off to protect the BMS. It's more common in the first few cycles before the IC has recalibrated. Run the recalibration cycle first; if shutdowns continue after three full cycles, measure resting cell voltage — it should read above 3.6V at the point of shutoff.