C4D10T Nokia Tango Compatible Battery 3.7V 1700mAh Li-ion

SVP Tango / Deco Pro — 3.7V Li-ion Replacement Battery (C4D10T)

This is a 3.7V Li-ion cell rated at 1700mAh (6.29Wh), supplied as a direct swap for the original battery in the Nokia Tango and SVP Deco Pro smartphones. It uses OEM part references C4D10T and N4D113J. Both phones share the same battery bay dimensions — 66.20 x 44.00 x 5.10mm — and the same voltage rail.

• Tango and Deco Pro compatibility: Both models run a 3.7V single-cell architecture with the same connector pinout and physical footprint. The BMS in each device communicates on the same signal line, so the same cell serves both without any adapter or modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Tango platform and monitored BMS handshake, charge acceptance at full current, and cutoff behaviour at the lower voltage threshold. The cell accepted full charge without triggering any protection flags.
• Fuel gauge recalibration on first cycle: On first use after fitting, disable fast charging and run one full discharge down to automatic shutdown, then charge uninterrupted to 100%. This gives the phone's fuel gauge IC a clean reference curve for the new cell before any high-current charging session pushes current into an uncalibrated state.

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

The Tango's modem and display together pull peak current that a degraded or freshly installed cell may not sustain cleanly. When cell voltage sags below the BMS cutoff threshold under that combined load, the phone shuts down even though the fuel gauge still reads 20–30%. This is a voltage cliff issue, not a capacity issue. The replacement cell resolves the sag, but the fuel gauge IC needs one full discharge-charge cycle to map the new cell's voltage curve accurately before percentage readings stabilise.

Phone warm near the battery during the first charge after replacement

A new cell arrives with elevated internal impedance compared to a broken-in cell. During the first charge, the Tango's charge IC pushes current into that higher-impedance cell, which converts more energy to heat than usual. This is expected on cycle one and typically resolves by cycle two or three as impedance drops. If the phone stays warm beyond the third full charge, check that the battery contacts are seated flush and that no debris is caught between the cell and the rear cover.