About this replacement
BLU Dash L2 / D250 / Dash L3 / D390 — 3.7V Li-ion Replacement Battery (C505629140T)
This is a 3.7V, 1400mAh (5.18Wh) Li-ion cell for the BLU Dash L2, D250, Dash L3, and D390 smartphones. It replaces OEM part numbers C505629140T, C505629140I, and C505629140L. If your original cell has swollen, no longer holds a charge, or the phone shuts off unexpectedly, this is the direct swap.
- Dash L2, D250, Dash L3, D390 fitment: These four models share the same battery bay dimensions and connector pinout. The 53.50 × 49.84 × 4.92mm form factor and three-pin connector are consistent across the series, so one cell covers all four.
- Bench tested on actual hardware: We cycled this cell through full discharge and charge passes on the Dash L2. The BMS held the charge cutoff correctly at 4.2V and the protection circuit tripped as expected on overcurrent — no thermal events, no false low-battery shutoffs during the test sequence.
- Fuel gauge recalibration on first install: After fitting this cell, run one complete discharge to auto-shutdown, then charge uninterrupted to 100% before normal use. The Dash L2's fuel gauge IC is calibrated to the old cell's discharge curve — skipping this step causes the percentage counter to read inaccurately for the first several cycles.
Sudden shutdown at 20–30% on the Dash L2 after cell replacement
This is a voltage cliff issue, not a faulty cell. A new Li-ion cell has a steeper voltage drop curve in the lower charge range than the aged cell the fuel gauge was trained on. When the modem fires up during a call or the screen brightness peaks, current draw spikes briefly. The fuel gauge IC reads a momentary voltage dip and triggers a low-voltage shutdown even though the displayed percentage still shows 20–30%. One full discharge-to-shutdown and uninterrupted recharge cycle resets the coulomb counter reference point and eliminates the premature cutoff.
Phone shows incorrect battery percentage after fitting the replacement cell
The fuel gauge IC on the Dash L2 stores a learned discharge profile from the original cell. When a new cell goes in, that stored profile no longer matches the actual voltage-to-capacity curve of the replacement. The percentage readout can jump erratically, stall at a fixed number for long periods, or drop suddenly by 15–20 points. Fix this by running the phone down until it powers off on its own, then charging to 100% in one session without unplugging — the IC writes a new baseline against the new cell and the readout stabilises within one to two additional cycles.