LeTV Max LT633 Replacement Battery 3.8V 3300mAh

LeTV Max / MX1 / X900 — 3.8V Li-Polymer Replacement Battery (LT633)

This 3.8V 3300mAh (12.54Wh) Li-Polymer cell replaces the original LT633 battery in the LeTV Max, MX1, and X900 smartphones. It fits the stock battery compartment and connects to the existing flex cable without modification. Replace this when the original cell no longer holds voltage under screen or modem load.

• Max, MX1, and X900 compatibility: All three models share the same battery bay dimensions, connector pinout, and BMS communication protocol — the LT633 part number covers the entire range without hardware changes.
• Bench tested on actual hardware: We ran the LT633 cell through charge and discharge cycles on the X900 platform. The BMS accepted charge current correctly, protection circuits tripped at expected voltage limits, and the fuel gauge IC picked up cell state within one full cycle.
• Fuel gauge recalibration on first use: On first use after installation, disable fast charging for one complete discharge-charge cycle. This lets the fuel gauge IC recalibrate against the new cell's discharge curve before high-current charging pushes current into an uncalibrated cell.

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

A new Li-Polymer cell has a slightly different voltage-versus-capacity curve than the aged cell it replaces. The fuel gauge IC still holds calibration data from the old cell, so it reads 25% remaining when the actual cell voltage has already dropped to the BMS cutoff threshold. Under modem transmit or display load, the voltage sag tips the BMS into protection cutoff and the phone shuts down hard. One full discharge-charge cycle — down to auto-off, then a full charge — forces the coulomb counter to resync against the new curve. Shutdowns at false-low percentages stop after that cycle.

Phone shows 100% instantly after replacement and drains in a straight line to zero

This is the fuel gauge IC reporting stale data — it locked onto the old cell's full-charge voltage and is not reading the new cell accurately. The percentage jumps to 100% fast because the new cell charges to a slightly higher open-circuit voltage than the depleted original. Drain looks linear because the IC is interpolating rather than measuring. Discharge the phone fully until it powers off automatically, then charge uninterrupted to 100% — after that single calibration cycle, percentage tracking stabilises.