Saiet Lumina 3G Replacement Battery 3.7V 800mAh Li-ion

Saiet Lumina 3G / One Max / Ready Series — 3.7V Li-ion Replacement Battery

This is a 3.7V, 800mAh (2.96Wh) lithium-ion cell for the Saiet Lumina 3G, One Max, Ready, and Ready Max smartphones. These compact devices share the same battery bay dimensions — 53.00 × 34.00 × 4.80mm — and the same voltage rail, so one cell fits the whole family. If your phone drains fast, shuts down unexpectedly, or won't hold a charge, this cell replaces the aged original.

• Lumina 3G / One Max / Ready family fit: These models share an identical battery footprint and 3.7V power rail. The connector orientation and BMS handshake points are consistent across the range, so one cell covers all listed variants without modification.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the Lumina 3G platform. The onboard charge IC accepted the cell without fault codes, and the BMS protection circuit tripped correctly at both high-voltage cutoff and low-voltage floor — no thermal events observed.
• Fuel gauge recalibration on first use: After fitting this cell, disable any fast-charge mode and run one full discharge-to-charge cycle before normal use. The fuel gauge IC on these Saiet devices calibrates its coulomb counter against the cell's discharge curve on the first full cycle — skipping this step causes erratic percentage readings for days afterward.

Sudden shutdown at 20–30% on the Saiet Lumina 3G

This is a voltage cliff problem, not a capacity problem. At 20–30% state-of-charge, an aging cell can no longer sustain voltage under the combined load of the modem radio and display backlight. The phone's power management IC sees voltage drop below its minimum threshold and cuts the system before the fuel gauge even registers empty. A fresh 800mAh cell restores the flat discharge curve these devices rely on, eliminating the premature cutoff.

Phone warm near the battery bay on the first few charges after replacement

A new lithium-ion cell has slightly higher internal impedance than a broken-in cell. On early charge cycles, the charge IC pushes current into that higher-impedance cell, generating more heat than you'd see later. This is normal for the first two or three full cycles and settles as impedance drops. If warmth persists beyond three cycles or the device gets hot to the touch, check that the replacement cell is seated flat — any edge lift increases contact resistance and compounds the heating.