Coolpad 5315 Replacement Battery CPLD-129 3.7V 2500mAh

Coolpad 5315 — 3.7V Li-ion Replacement Battery (CPLD-129)

This is a 3.7V, 2500mAh Li-ion cell built to replace the original CPLD-129 battery in the Coolpad 5315 smartphone. It fits the 5315 directly — same connector, same footprint at 80.00 × 65.00 × 4.30mm. Swap it when the original cell no longer holds charge or shuts the phone down unexpectedly.

• Coolpad 5315 fitment: The 5315 uses a dedicated connector and BMS handshake tied to the CPLD-129 cell spec. This replacement matches the 3.7V nominal rail and pin configuration so the charge IC accepts the cell without flagging an incompatible battery warning.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the 5315 platform. The BMS accepted the cell, charge termination triggered correctly at full voltage, and the coulomb counter tracked state-of-charge without error flags through multiple cycles.
• First-cycle fuel gauge recalibration: After installing this cell, disable fast charging and run one full discharge-to-charge cycle at standard rate. The fuel gauge IC on the 5315 is calibrated to the old cell's discharge curve — one slow cycle lets it remap against the new cell before high-current charging is applied.

Sudden shutdown at 20–30% on the Coolpad 5315

This happens when the cell voltage drops below the modem's minimum operating threshold under load, even though the fuel gauge still reads 20–30%. Aged cells develop high internal impedance — voltage sags sharply when the radio transmits or the screen peaks, tripping the protection circuit before the gauge catches up. A new CPLD-129 cell with lower impedance sustains voltage through those load spikes. After installation, confirm the phone stays on past 15% under a call or screen-on session — that confirms the voltage floor is holding.

Phone shows wrong percentage after cell replacement

The fuel gauge IC on the 5315 stores a learned discharge curve from the old cell. After a cell swap, it maps the new cell's voltage against that old curve, so percentage readings jump or read high until the IC relearns. Run one complete discharge — down to auto-shutdown — followed by a full uninterrupted charge at standard rate. That single cycle gives the coulomb counter enough data to reanchor its 0% and 100% endpoints. After that cycle, percentage tracking stabilises.