ANS F30 Smartphone Li-Ion Replacement Battery 3.7V 1300mAh

ANS F30 — 3.7V Li-ion Replacement Battery

This is a 3.7V, 1300mAh (4.81Wh) Li-ion cell built to fit the ANS F30 smartphone. It replaces the original cell when capacity has dropped or the battery no longer holds a charge through a normal day. Physical dimensions are 57.30 × 42.80 × 4.84mm — measure your original before fitting.

• ANS F30 fitment: The F30 uses a compact low-voltage Li-ion cell on a 3.7V nominal rail. This replacement matches that rail exactly, so the charge IC and fuel gauge IC see the same voltage window as the original cell.
• Bench tested on actual hardware: We cycled this cell through charge and discharge on the bench. The BMS held cutoff at the correct upper and lower voltage thresholds with no spurious trips during normal load.
• Fuel gauge recalibration on first use: After fitting, disable fast charging and run one full discharge-to-charge cycle before relying on the percentage readout. The F30's fuel gauge IC calibrates its coulomb counter against a new cell's discharge curve — skipping this step causes the OS to report inaccurate percentages for the first several days of use.

Sudden shutdown at 20–30% on the ANS F30 after a cell swap

This is a voltage cliff issue, not a capacity problem. A fresh Li-ion cell has a slightly different discharge curve than the aged cell the fuel gauge IC was calibrated to. When the modem fires or the screen wakes at high brightness, current draw spikes and cell voltage drops below the BMS cutoff threshold — even though the OS still shows 20–30% remaining. One full discharge-charge cycle lets the coulomb counter re-anchor to the new cell's actual curve. After that cycle, the percentage readout and the real remaining charge align closely enough that the F30 stops cutting out early.

ANS F30 feels warm near the battery during the first few charges

A new, uncycled Li-ion cell has higher internal impedance than a broken-in cell. The charge IC pushes current into that higher impedance, and the extra resistance converts to heat. This is normal for the first two or three charge cycles and reduces as impedance drops with cycling. If the phone still runs noticeably warm after five full cycles, check that the charge IC is not stuck in a fast-charge mode — drop to a standard 5V/1A charger and confirm the back of the phone stays close to ambient temperature.