Wiko Pulp 3G Compatible Battery 3.8V 2500mAh 5251

Wiko Pulp 3G / Pulp 4G / Robby / Rainbow Jam 4G — 3.8V Li-Polymer Replacement Battery (5251)

This 3.8V, 2500mAh Li-Polymer cell replaces OEM part 5251 (also cross-referenced as S104-V02000-012, S104-V02000-001, and S104-V02000-000). It fits the Wiko Pulp 3G, Pulp 4G, Robby, and Rainbow Jam 4G smartphones. At 76.95 × 59.95 × 4.20mm, it matches the original cell footprint and connector position exactly.

• Pulp 3G / Pulp 4G / Robby / Rainbow Jam 4G compatibility: These models share the same battery bay dimensions, 3.8V nominal voltage rail, and three-pin connector pinout, which is why they all draw from the same OEM part family. The BMS handshake on each device accepts this cell without triggering an unrecognised-battery warning.
• Bench tested on actual hardware: We cycled this cell on a Pulp 3G unit, monitoring charge termination voltage and BMS cutoff under simulated screen-on and modem load. The protection circuit held the low-voltage cutoff at 3.0V and terminated charge correctly at 4.35V — no anomalous shutdowns across three full cycles.
• 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 the charge IC pushes higher current into an uncalibrated cell — preventing erratic percentage readings from the first hour.

Why the Pulp 3G reports wrong battery percentage after a cell swap

The Wiko Pulp 3G uses a coulomb-counter fuel gauge IC that builds its charge model against the old cell's internal resistance and discharge curve. When a new cell goes in, the stored model no longer matches reality — the phone reads "40%" while the cell voltage is already near cutoff. One full, uninterrupted discharge down to automatic shutdown followed by a complete charge to 100% resets the learned curve. After that cycle, percentage accuracy returns to within a few percent across the full range.

Sudden shutdown at 20–30% remaining on the new cell

This is a voltage-cliff failure, not a capacity problem. Under combined 3G modem and display load, the Pulp 3G draws enough current that a cell with any elevated internal resistance drops below the BMS cutoff threshold — around 3.0V — even though the fuel gauge still shows charge remaining. A fresh Li-Polymer cell at 2500mAh should sustain load voltage well above 3.2V at 30% state-of-charge. If shutdowns persist after the calibration cycle described above, check that the battery connector tabs are fully seated — a partially connected terminal increases effective resistance and worsens voltage sag under load.