BoostMobile VENI Replacement Battery 3.7V 1200mAh Li-ion

BoostMobile VENI / LG730 — 3.7V Li-ion 1200mAh Replacement Battery

This is a 3.7V Li-ion cell rated at 1200mAh (4.44Wh), built to fit the BoostMobile VENI and LG730 smartphones. It slots into the same battery bay as the original and connects to the same charge management circuit. If your original cell is swelling, draining fast, or no longer holding a charge, this is the direct swap.

• VENI and LG730 compatibility: Both handsets share the same battery bay dimensions, voltage rail, and connector pinout — 65.20 × 44.00 × 4.80mm with a matching 3.7V charge profile. The BMS on each device reads the same termination voltage, so the charge IC behaves identically across both models.
• Bench tested on actual hardware: We ran this cell through charge and discharge cycles on the LG730 platform. The BMS accepted the cell without fault flags, charge termination triggered correctly at 4.2V, and low-voltage cutoff engaged as expected before hitting the deep-discharge threshold.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging and run one full discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's actual discharge curve before the coulomb counter starts reporting state-of-charge. Skipping this step causes the percentage readout to drift or jump until the IC recalibrates itself.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff issue, not a capacity defect. Under peak modem or screen load, the cell voltage can drop sharply even when the reported percentage looks healthy. The phone's protection circuit reads a voltage sag below its cutoff threshold and shuts down to protect the cell — regardless of what the fuel gauge is showing. After the shutdown, the phone may power back on and report 25% again, which confirms the fuel gauge IC is working from a stale calibration curve. Run one full discharge-charge cycle with fast charging disabled, and the shutdowns will stop once the IC re-learns where the voltage cliff actually sits on this cell.

Phone won't power on after the replacement cell sat in storage

Li-ion cells in storage self-discharge over time. If the cell drops below approximately 2.5V per cell, the BMS enters lockout mode and blocks charging to prevent damage to a critically depleted cell. Plugging into a standard charger at this point produces no response — no charging indicator, no boot. Connect the phone to a wall adapter (not a USB port) and leave it for 20–30 minutes without attempting to power it on. Most BMS circuits include a trickle pre-charge path that slowly raises the cell voltage back above the lockout threshold; once it clears roughly 2.8V, normal charging resumes and the phone will power on.