About this replacement
Coolpad K1 / 7620L / 5952 / 8729 — 3.7V Li-ion Replacement Battery (CPLD-327)
This is a 3.7V, 1950mAh (7.22Wh) Li-ion cell built to the CPLD-327 specification. It fits the Coolpad K1, 7620L, 5952, and 8729 smartphones. It slots into the original battery bay and connects to the same three-contact ribbon used across this device family.
- K1, 7620L, 5952, and 8729 compatibility: These four models share the same physical bay dimensions, the same three-pin connector layout, and the same BMS handshake voltage thresholds — that is why a single CPLD-327 cell works across all of them without modification.
- Bench tested on actual hardware: We ran this cell through a full charge-discharge cycle on a K1 unit. The BMS accepted the charge handshake immediately, cutoff triggered cleanly at the rated low-voltage threshold, and the charge IC held steady at 4.2V terminal voltage with no runaway or false termination.
- Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and let the phone run one full discharge-to-charge cycle. The fuel gauge IC calibrates its coulomb counter against this new cell's discharge curve — skipping this step is what causes the erratic percentage jumps buyers report in the first 24 hours.
Sudden shutdown at 20–30% on the Coolpad K1
This is a voltage cliff problem, not a capacity problem. When the modem fires during a call or the display hits full brightness, current draw spikes sharply. If the cell's internal impedance is elevated — common in aged or deeply discharged cells — terminal voltage drops below the BMS cutoff threshold even though the fuel gauge still shows charge remaining. The phone cuts out because the BMS is reading true cell voltage, not the percentage on screen. Fitting a fresh CPLD-327 cell and completing one full calibration cycle resolves the gap between reported percentage and actual cutoff voltage.
Phone stays dark after storage — won't respond to charger
If the original cell sat discharged for weeks, it likely dropped below 2.5V per cell — the point at which the BMS locks out to prevent unsafe charging. The phone will not respond to a standard charger connection at this voltage. To recover, connect the device and leave it on a low-current USB charger (500mA or below) for 20–30 minutes before attempting a normal boot. If the cell does not recover to at least 3.0V within that window, the cell is unrecoverable and a replacement CPLD-327 cell is the correct next step.