About this replacement
Motorola Moto G5S / G6 Series — 3.8V Li-Polymer Replacement Battery (HG30)
This is a 3.8V, 2700mAh Li-Polymer replacement battery for the Motorola Moto G5S, XT1794, Moto G6, and XT1925-13, among other compatible variants. It uses OEM part number HG30 and matches the original cell's voltage, capacity, and connector layout. If your G5S or G6 shuts down early or won't hold charge, swapping the cell is the fix.
- G5S and G6 compatibility: These models share the HG30 form factor — same 3.8V rail, same flex connector, and the same BMS communication protocol. Swapping between G5S and G6 variants works because the charge IC on both boards reads the same cell parameters.
- Bench tested on actual hardware: We cycled this cell through charge and discharge on a G5S board. The BMS accepted the cell on first connection, held charge termination at 4.35V, and did not trigger an overcurrent cutoff during screen-on load.
- Fuel gauge recalibration on first use: On first installation, disable fast charging and run one complete discharge-charge cycle at standard current. This lets the fuel gauge IC map the new cell's discharge curve before the charge IC starts pushing high current into an uncalibrated state.
Sudden shutdown at 20–30% on the G5S after a cell swap
This is a voltage cliff issue, not a capacity issue. Under combined modem and display load, the new cell's internal resistance causes the voltage to sag below the BMS cutoff threshold before the fuel gauge reaches 0%. The fuel gauge IC is still calibrated to the old cell's discharge curve, so it reads 25% while the actual cell voltage is already near 3.4V. One full discharge-charge cycle corrects the coulomb counter and eliminates these early shutdowns.
Fast charging not working on the first cycle after replacement
Motorola's adaptive charging protocol negotiates current limits with the charge IC based on cell state data. On a fresh cell with no cycle history, the charge IC defaults to a conservative current profile until the BMS has logged at least one full cycle. This is expected behaviour, not a fault with the replacement cell. After the first complete discharge-charge cycle at standard current, fast charge resumes normally on both G5S and G6 hardware.