About this replacement
LeTV 1 / X600 — 3.8V Li-Polymer Replacement Battery (LT55B)
This is a 3.8V 3000mAh (11.4Wh) Li-Polymer replacement battery for the LeTV 1 and X600 smartphones. It uses OEM part number LT55B and fits the original battery bay without modification. Swap it when the original cell no longer holds a usable charge or triggers unexpected shutdowns.
- LeTV 1 and X600 compatibility: Both models share the same battery bay dimensions, connector pinout, and BMS handshake protocol — one cell fits both. The LT55B form factor is 75.03 × 60.26 × 4.80mm, matching the original cavity exactly.
- Bench tested on actual hardware: We ran this cell through charge and discharge cycles on a LeTV X600 unit. The BMS accepted the new cell without a fault code, and the charge IC reached full cutoff voltage at 4.35V as expected.
- First-cycle fuel gauge recalibration: After fitting this battery, disable fast charging and run one full discharge-to-charge cycle at standard rate. The fuel gauge IC in the LeTV 1 calibrates its coulomb counter against the new cell's discharge curve — skipping this step causes the OS to misread remaining capacity for the first several cycles.
Sudden shutdown at 20–30% on the LeTV 1 after a cell swap
This happens because the fuel gauge IC still holds the discharge curve of the old, degraded cell. When a fresh cell is installed, the stored curve doesn't match the new cell's voltage behaviour under load. The modem and display pull current spikes that cause the cell voltage to sag below the BMS cutoff threshold — even though the percentage indicator still shows charge remaining. One full discharge cycle at standard charge rate forces the coulomb counter to relearn the curve and eliminates most false shutdowns.
LeTV X600 not powering on after the replacement battery sat in storage
Li-Polymer cells self-discharge during storage. If the cell voltage dropped below approximately 2.5V per cell, the BMS trips into deep-discharge lockout to prevent damage. The phone will show no response to the power button and may not trigger the charging indicator immediately. Connect a charger and leave it for 15–20 minutes — the charge IC will trickle current into the cell until voltage recovers above the BMS re-enable threshold, typically around 3.0V, at which point normal charging resumes.