LG V40 BL-T41 Replacement Battery 3.85V 3400mAh

LG V40 ThinQ — 3.85V Li-Polymer Replacement Battery (BL-T41)

This is a 3400mAh, 3.85V lithium-polymer replacement battery for the LG V40 ThinQ smartphone. It carries OEM part number BL-T41 and fits the V40, V405UAB, V40 ThinQ, and V40 ThinQ VZW LTE-A, along with 24 additional V40 variants. Capacity is rated at 13.09Wh.

• V40 ThinQ platform fit: All V40 variants in this lineup share the same BL-T41 footprint, voltage rail, and BMS handshake. The connector pinout and cell dimensions — 84.80 × 42.40 × 5.10mm — are consistent across the full V40 series, so one cell covers the entire platform.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on V40 hardware. The BMS accepted charge initiation without error, current tapered correctly at top-of-charge, and the protection circuit tripped cleanly at the low-voltage cutoff — no false flags from the fuel gauge IC.
• First-cycle calibration tip: On first use after installation, disable fast charging and run one complete discharge-charge cycle at standard rate. This lets the fuel gauge IC build an accurate discharge curve against the new cell before high-current fast charging pushes current into an uncalibrated cell.

Sudden shutdown at 20–30% on the V40 after a cell swap

This is a voltage cliff problem, not a capacity problem. The V40's Snapdragon 845 and modem draw a sharp current spike under LTE load or screen-on events. If the fuel gauge IC is still calibrated to the old cell's discharge curve, it reports 25% remaining while the new cell's actual voltage drops below the shutdown threshold under load. The phone cuts out before the OS has time to log a low-battery warning. Run one full discharge to near-zero, then charge uninterrupted to 100% — this recalibrates the coulomb counter to the new cell curve.

USB-PD fast charge not accepted on the first cycle after replacement

After installing a new BL-T41 cell, some V40 units refuse fast charge on the first plug-in — the charging icon shows standard rate even with a Qualcomm Quick Charge brick. The charge IC runs a brief handshake with the BMS on a fresh cell and defaults to a conservative current limit until it confirms cell health. This is normal behaviour, not a fault. Charge once at standard rate to completion, then reconnect with your fast-charge adapter — the IC will accept the higher current rate from the second cycle onward.