LG Optimus LTE BL-49KH Replacement Battery 3.7V 1300mAh

LG Optimus LTE / Nitro HD — 3.7V Li-ion Replacement Battery (BL-49KH)

This is a 3.7V, 1300mAh Li-ion replacement battery for the LG Optimus LTE, LU6200, SU640, and Nitro HD. It slots into any handset in this family that uses the BL-49KH cell. Voltage and connector match the original spec exactly.

• Optimus LTE and Nitro HD platform fit: These models share the same battery bay dimensions, 3.7V nominal voltage rail, and BL-49KH connector pinout. The BMS handshake protocol is identical across the LU6200 and SU640 variants, so one cell covers the full group.
• Bench tested on actual hardware: We cycled this cell through full charge and discharge on an Optimus LTE unit. The BMS accepted the charge handshake on the first connection, hit the correct 4.2V charge cutoff, and the protection circuit tripped cleanly at the low-voltage threshold without dropping the device mid-session.
• Fuel gauge recalibration after swap: On first use, disable any fast-charge adapter and run one complete discharge-to-charge cycle at standard current. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before higher charge rates are applied to an uncalibrated cell.

Sudden shutdown at 20–30% on the BL-49KH replacement cell

The Optimus LTE's modem and display draw sharp current spikes that can pull the cell voltage below the BMS cutoff threshold even when the fuel gauge still reads 20–30%. A new cell with an uncalibrated fuel gauge IC makes this worse — the reported percentage drifts high relative to actual usable capacity. This is not a faulty battery; it is the coulomb counter working from the old cell's discharge curve. One full discharge cycle down to automatic shutdown, followed by an uninterrupted charge to 100%, resets the calibration and tightens the percentage readout.

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

Li-ion cells self-discharge during storage, and the BL-49KH will drop below the BMS reactivation threshold of approximately 2.5V per cell if left uncharged for several months before installation. When this happens, the phone shows no boot screen and no charging indicator. Connect the handset to a wall charger — not a PC USB port — and leave it for 15–20 minutes before attempting to power on. Most BMS circuits on this cell will accept a trickle recovery charge from a 5V wall adapter and unlock normal operation once the cell climbs back above 3.0V.