About this replacement
Coolpad D508 / D510 / 2168 / D21 — 3.7V Li-ion Replacement Battery (CPLD-30 / CPLD-63)
This is a 3.7V, 2000mAh (7.4Wh) Li-ion cell for the Coolpad D508, D510, 2168, and D21 smartphones. It replaces OEM parts CPLD-30 and CPLD-63. If your original cell no longer holds a charge or the phone shuts down unexpectedly, this is the direct swap.
- D508 / D510 / 2168 / D21 compatibility: These models share the same battery footprint, connector pinout, and 3.7V nominal voltage rail. The BMS handshake protocol is identical across the group, so one cell covers all four devices without modification.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge on a D510 unit. The BMS accepted the charge handshake on the first connection, hit the 4.2V upper cutoff cleanly, and held voltage within spec across the full discharge curve.
- 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 its coulomb counter against the new cell's actual discharge curve before high-current charging pushes current into an uncalibrated cell.
Sudden shutdown at 20–30% on the Coolpad D508 after a cell swap
This is a voltage cliff issue, not a capacity defect. The fuel gauge IC on the D508 is still reading from the discharge curve of the old, degraded cell. When the new cell hits a load spike — modem TX burst or screen at full brightness — voltage momentarily drops below the threshold the OS has mapped as "safe," and the phone cuts power. The fix is one full uninterrupted discharge down to auto-shutoff, then a full charge to 100% with the screen off. After that cycle, the coulomb counter resets to the new cell's curve and the percentage readings stabilise.
Phone won't power on after the replacement cell sat in storage
Li-ion cells self-discharge at roughly 2–3% per month. If a replacement cell shipped or sat in a drawer long enough, it can drop below 2.5V — the threshold where the BMS locks out to prevent deep-discharge damage. The D508 will show nothing when you press the power button: no logo, no vibration. Connect the phone to a wall charger (not a PC USB port — too low current) and leave it for 15–20 minutes before attempting to power on. Most BMS circuits on this platform begin trickle-charge recovery at around 2.5V and unlock normal charging once the cell reaches 3.0V.