About this replacement
LG Rebel 2 / Aristo Series — 3.85V Li-ion Replacement Battery (BL-45F1F)
This is a 3.85V, 2000mAh Li-ion replacement battery for the LG Rebel 2, Aristo, L57BL, L58VL, and related variants using OEM part number BL-45F1F. It physically matches the original cell dimensions (75.18 × 50.10 × 4.42mm) and uses the same connector and BMS contact layout. Swap it in when the original cell no longer holds charge through a normal day of calls, messaging, and background data.
- Rebel 2 / Aristo platform compatibility: The L57BL, L58VL, Aristo, and Rebel 2 all share the same battery bay dimensions, BMS contact pinout, and 3.85V voltage rail — which is why one cell number covers the full group. The BMS handshake between battery and charge IC is identical across these variants.
- Bench tested on actual hardware: We cycled this cell on the Rebel 2 platform and confirmed the BMS communicates correctly with the charge IC at full current. Capacity read-back at the fuel gauge matched the rated 2000mAh within normal cell tolerance on the second full cycle.
- Fuel gauge recalibration after install: On first use after installation, disable fast charging and run one complete discharge-to-charge cycle. This lets the fuel gauge IC map the new cell's discharge curve before high-current charging pushes into an uncalibrated state — skipping this step is the main cause of erratic percentage readings in the first few days.
Why the Rebel 2 shuts down suddenly at 20–30% after a cell swap
The Rebel 2's fuel gauge IC holds a charge curve learned from the old, degraded cell. When the new cell is installed, the IC still uses that old curve as its reference. At around 20–30% reported charge, the modem or screen draws a brief high-current spike that the old curve predicts the cell cannot handle — so the IC triggers a protective shutdown. The phone still has real charge left; the gauge simply doesn't know it yet. One full discharge-to-charge cycle clears the stored curve and writes a new one matched to the replacement cell.
Phone won't power on after the replacement battery sat in storage
Li-ion cells self-discharge in storage, and if the cell voltage drops below roughly 2.5V per cell, the BMS locks out to prevent damage — the phone will show nothing when you press the power button. Connect the phone to a wall charger (not a PC USB port) and leave it for 15–20 minutes without attempting to power on. The charge IC needs to trickle current into the cell until it clears the BMS lockout threshold, typically around 2.8–3.0V, before the phone will boot. If no charge indicator appears after 30 minutes on a wall adapter, check that the battery contacts are fully seated.