SRF StarAddict Replacement Battery 3.7V 1100mAh Li-ion

SRF StarAddict — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1100mAh Li-ion cell for the SRF StarAddict smartphone. It fits the original battery bay and connects to the same charge IC the phone uses to manage cell voltage. Capacity figures are taken from the product specification — 4.07Wh total energy.

• StarAddict platform fit: The StarAddict uses a single-cell 3.7V nominal architecture. This cell matches that voltage rail and the physical footprint — 84 × 34 × 4mm — so the connector seats without modification to the housing.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the StarAddict platform. The BMS accepted charge without fault codes, held voltage above 3.5V through mid-discharge, and cut off cleanly at the low-voltage threshold without triggering a hard shutdown loop.
• Fuel gauge recalibration on first cycle: On first use after installation, disable fast charging and run one full discharge-to-charge cycle. This lets the fuel gauge IC map its coulomb counter against the new cell's actual discharge curve before high-current charging pushes current into an uncalibrated state.

Sudden shutdown at 20–30% on the replacement cell

This is a voltage cliff problem, not a capacity problem. When the modem, screen backlight, or both fire simultaneously, they pull a short high-current burst. If the cell voltage sags below the BMS cutoff threshold under that load — even briefly — the phone powers off. A new cell on its first few cycles has not yet reached minimum internal resistance, so the sag can be steeper than expected. Run two or three full discharge-charge cycles and the sag narrows. If it persists past cycle three, check that the cell connector is fully seated — a partial connection raises contact resistance and worsens voltage sag under load.

Phone shows wrong battery percentage after cell swap

The StarAddict's fuel gauge IC stores a learned discharge curve from the old cell. After a swap, that stored curve no longer matches the new cell's actual voltage-to-capacity relationship, so the percentage reading drifts — often reading full at 80% or dropping suddenly near the end. One complete discharge from 100% down to auto-shutoff, followed by a full charge uninterrupted to 100%, forces the coulomb counter to resync against the new cell. Do not interrupt that first cycle. After it completes, the percentage display stabilises within one to two further cycles.