About this replacement
HiBy R5 Hi-Res Portable Android Music Player — 3.8V Li-Polymer Replacement Battery (654779P)
This 3.8V, 3100mAh Li-Polymer battery replaces part number 654779P in the HiBy R5 and R5 Hi-Res Portable Android Music Player. It restores full operating capacity when the original cell has degraded from repeated charge cycles. Dimensions are 71.90 × 44.00 × 7.20mm — verify clearance before installing.
- R5 and R5 Hi-Res compatibility: Both R5 variants share the same cell format, connector, and BMS handshake protocol. The 654779P footprint is identical across the range, so one replacement covers both builds.
- Bench tested on actual hardware: We ran this cell through full charge and discharge cycles on the R5 platform. The BMS accepted the cell without error flags, and the protection circuit responded correctly to both overvoltage and undervoltage cutoff thresholds.
- Post-swap initialisation on the R5: After fitting a new cell, charge the R5 to 100% before first use. Media players frequently enter deep-discharge protection after a cell swap and require a slow trickle charge before the device accepts normal charge current from its USB-C port.
Battery percentage jumping after cell swap on the R5
The R5 tracks battery state using voltage thresholds calibrated to the original cell's discharge curve. A new cell produces slightly different voltage readings at each charge level, so the percentage indicator recalibrates over the first few cycles. Expect erratic readings — jumping from 80% to 45% mid-session — for the first two or three full charge and discharge cycles. The indicator stabilises once the device's fuel gauge has mapped the new cell's actual voltage curve.
Playback cutting out before the battery indicator shows empty
The R5's audio amplifier draws a sharp current spike when driving demanding headphone loads, particularly low-impedance or planar magnetic drivers. Near the end of a cell's discharge curve, voltage sags under that load and drops below the amplifier's minimum operating threshold — even while the UI still shows charge remaining. This is a cell-level voltage sag issue, not a firmware fault. If this happens consistently, discharge the player fully, then charge to 100% to allow the fuel gauge to reset its empty threshold to 3.2V.