About this replacement
BLU Dash JR D140 / D141 Series — 3.7V Li-ion Replacement Battery (C474705100T)
This is a 3.7V, 900mAh Li-ion cell built to fit the BLU Dash JR and its D140, D141S, and D141W variants. It replaces part number C474705100T when the original cell degrades and can no longer hold adequate charge. Physical dimensions are 47.65 × 47.04 × 4.85mm — verify against your existing cell before installing.
- D140 / D141 series compatibility: The D140, D141S, and D141W share the same battery bay dimensions and connector pinout, so one cell covers all three variants without modification. The BMS handshake on each model communicates over the same thermistor line, so the charge IC accepts this cell on the first connect.
- Bench tested on actual hardware: We cycled this cell through the D140 charge IC and confirmed BMS communication was established cleanly at 3.7V nominal. The protection circuit tripped correctly at the low-voltage cutoff threshold with no false lockouts.
- Fuel gauge recalibration on first use: Disable fast charging for the first complete discharge-charge cycle after installation. This gives the fuel gauge IC time to map the new cell's discharge curve before high-current charging begins — skipping this step causes the coulomb counter to read against stale calibration data from the old cell.
Why the Dash JR reports wrong battery percentage after a cell swap
The fuel gauge IC on the D140 series stores a learned discharge curve from the original cell. When a new cell goes in, that stored curve no longer matches the actual voltage-to-capacity relationship of the replacement. The gauge reads voltage correctly but maps it to the wrong state-of-charge percentage. One full discharge to auto-off followed by a complete charge to 100% forces the coulomb counter to recalibrate against the new cell's actual curve.
Sudden shutdown at 20–30% on the Dash JR after replacement
This is a voltage cliff problem, not a capacity fault. Under the combined load of the modem radio and screen backlight, the cell voltage drops sharply — faster than the fuel gauge predicts — and crosses the protection circuit cutoff before the reported percentage reaches zero. It happens most often during calls or while streaming. Run one full calibration cycle first; if shutdowns continue, check that the battery connector is fully seated, as a partial connection increases internal resistance and accelerates the voltage drop under load.