T-Mobile TMAF025G Compatible Battery 3.85V 4000mAh

T-Mobile TMAF025G / Revvl 6 5G — 3.85V Li-Polymer Replacement Battery (RE001)

This is a 3.85V, 4000mAh (15.4Wh) Li-Polymer battery for the T-Mobile TMAF025G and Revvl 6 5G smartphones. It replaces the original RE001 cell when the existing battery no longer holds a usable charge. Dimensions are 87.20 × 64.00 × 4.20mm — confirm before ordering if you have an aftermarket shell.

• TMAF025G and Revvl 6 5G compatibility: Both model names refer to the same hardware platform. They share the same battery bay, connector pinout, and BMS handshake protocol, so one cell covers both SKUs without modification.
• Bench tested on actual hardware: We ran this cell through a full charge-discharge cycle on a Revvl 6 5G unit. The BMS accepted charge current correctly, reported state-of-charge to the OS without error flags, and held voltage above 3.6V through the mid-cycle load.
• First-cycle fast charge protocol: On first use after installation, disable fast charging for one complete discharge-charge cycle. The fuel gauge IC is calibrated to the old cell's discharge curve. Running a slow cycle first lets the coulomb counter re-anchor to the new cell before high-current fast charging begins.

Sudden shutdown at 20–30% on the Revvl 6 5G after a cell swap

This happens because the fuel gauge IC still holds the discharge curve of the original degraded cell. When load spikes — 5G modem, screen at full brightness, background sync — the new cell's voltage drops faster than the IC expects at that state-of-charge. The phone reads the voltage dip as a near-empty condition and triggers an emergency shutdown. One full slow discharge to automatic power-off, followed by an uninterrupted charge to 100%, resets the coulomb counter and stops the early shutdowns.

Battery percentage jumping erratically after replacement

Erratic percentage readings — jumping from 60% to 40% or spiking upward mid-discharge — point to a fuel gauge IC that hasn't mapped the new cell yet. The IC uses a stored charge curve from the old cell to estimate remaining capacity, and a fresh cell with different internal resistance throws those estimates off. This is not a faulty battery. Perform two full uninterrupted discharge-to-shutdown and charge-to-100% cycles with fast charging disabled. After the second cycle, readings stabilise as the IC completes recalibration.