BLU Dash 4.0 Replacement Battery 3.7V 1500mAh C684804150T

BLU Dash 4.0 / D270 Series — 3.7V Li-ion Replacement Battery (C684804150T)

This is a 3.7V, 1500mAh Li-ion replacement battery for the BLU Dash 4.0 smartphone and its variants — D270, D270a, and D272. It slots into the same battery bay as the original cell and connects to the same three-contact ribbon. Capacity is 1500mAh (5.55Wh), matching the factory specification.

• D270 / D270a / D272 fit: These models share the same battery bay dimensions (68.45 × 48.00 × 4.20mm), identical connector pitch, and the same BMS handshake protocol — one cell fits all variants without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on a D270 unit. The BMS accepted the charge current without tripping, and the protection circuit responded correctly at low-voltage cutoff.
• Fuel gauge recalibration on first install: On first use after installation, disable fast charging and run one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before interpreting state-of-charge data — skipping this step causes percentage jumps and premature low-battery warnings.

Why the Dash 4.0 reports wrong battery percentage after a cell swap

The Dash 4.0 uses a fuel gauge IC that builds its state-of-charge model from the discharge curve of the previous cell. When a new cell goes in, the IC is still referencing the old curve — often an aged, degraded one. The mismatch makes the reported percentage inaccurate until the IC relearns. One full discharge to auto-off followed by an uninterrupted charge to 100% resets the coulomb counter and re-establishes an accurate curve. After that single cycle, percentage readings stabilise.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff issue, not a capacity fault. When the modem transmits or the screen brightness peaks, current draw spikes and the cell voltage drops sharply — if it dips below the BMS cutoff threshold, the phone shuts off even though the gauge still shows charge remaining. On a freshly installed, uncalibrated cell this happens more often because the IC hasn't yet mapped the voltage-to-capacity curve accurately. Run one full discharge-charge cycle first. If shutdowns continue, check that no background apps are spiking CPU load — sustained high draw accelerates the voltage sag that triggers cutoff.