About this replacement
Aspera R5 — 3.7V Li-ion Replacement Battery (R5-B)
This is a 3.7V 3000mAh Li-ion battery for the Aspera R5 smartphone. It replaces the original cell when capacity has dropped or the battery no longer holds a charge. Voltage and capacity match the R5's charge IC requirements exactly.
- Aspera R5 compatibility: The R5 uses a fixed connector pinout and a 3.7V nominal cell. This battery matches that pinout and voltage rail, so the phone's BMS can communicate charge state and temperature data without throwing a battery fault.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge sequences on an R5 unit and confirmed BMS handshake, charge termination at 4.2V, and stable voltage through the mid-range discharge curve.
- Fuel gauge recalibration on first use: On first installation, disable fast charging and run one complete discharge down to auto-shutoff, then charge to 100% without interruption. This lets the R5's fuel gauge IC map its coulomb counter to the new cell's actual discharge curve before resuming normal use.
Sudden shutdown at 20–30% on the Aspera R5 after a cell swap
The R5's fuel gauge IC stores a discharge curve calibrated to the original cell. A new cell has a different internal resistance profile, so the IC misreads voltage under load — it reports 25% remaining while the cell has already dropped below the modem's minimum voltage threshold. The phone shuts down to protect the radio hardware, not because the battery is faulty. One full uninterrupted discharge-to-charge cycle resets the coulomb counter and eliminates these early shutoffs.
Aspera R5 showing incorrect battery percentage after replacement
After swapping the cell, the fuel gauge IC is still running the old cell's calibration data. Until it relearns the new cell's charge curve, percentage readings will jump — often showing 100% immediately after a short charge, or dropping several percent in seconds under screen load. This is a software calibration issue, not a defective battery. Let the R5 run down to auto-shutoff once, then charge uninterrupted to 100% to force the IC to recalibrate against the new cell.