BLU Neo X C825837200L Replacement Battery 3.7V 1450mAh

BLU Neo X / N070u — 3.7V Li-ion Replacement Battery (C825837200L)

This is a 3.7V, 1450mAh (5.37Wh) Li-ion battery for the BLU Neo X and N070u smartphones. It replaces OEM part C825837200L. The cell matches the original's physical dimensions — 82.02 × 57.75 × 3.22mm — so it seats correctly in the battery bay without modification.

• Neo X and N070u compatibility: Both model designations share the same battery bay dimensions, connector pinout, and BMS handshake protocol. One cell covers both variants.
• Bench tested on actual hardware: We cycled this cell through a full charge-discharge sequence on a Neo X unit. The BMS accepted the cell without fault flags, and the charge IC reached termination voltage correctly at 4.2V.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging begins on an uncalibrated state-of-charge register.

Sudden shutdown at 20–30% on the BLU Neo X after a cell swap

This happens because the fuel gauge IC is still reading the old cell's voltage-to-capacity curve. When the modem fires up during a call or the screen hits full brightness, current draw spikes and the new cell's terminal voltage drops faster than the IC expects. The phone interprets this as a critical low-voltage event and shuts down — even though the displayed percentage read 20% or higher. Run one full discharge to below 5% followed by an uninterrupted charge to 100% to push the coulomb counter through a complete calibration cycle.

BLU Neo X not powering on after the battery sat in storage

Li-ion cells self-discharge in storage. If the cell voltage dropped below approximately 2.5V, the BMS enters a lockout state to prevent unsafe charging of a deeply discharged cell. Plugging straight into a fast charger won't override this — the BMS will block the charge path. Connect to a low-current USB source, such as a PC USB-A port, for 15–20 minutes first. This trickle input nudges the cell voltage above the BMS recovery threshold, typically around 2.9V, at which point normal charging resumes.