About this replacement
Ezviz S5 Plus / S5 Plus Sports — 3.8V Li-ion Replacement Battery (BL-05)
This is a 3.8V, 1100mAh Li-ion replacement battery for the Ezviz S5 Plus and S5 Plus Sports Wi-Fi security cameras. It replaces the OEM BL-05 cell when the original pack loses capacity or fails completely. Swapping this cell restores the camera's ability to record and monitor without replacing the entire unit.
- S5 Plus and S5 Plus Sports compatibility: Both models share the same BL-05 cell format, voltage rail, and connector footprint. The BMS in each variant reads the same charge thresholds, so one cell covers both camera bodies without any wiring or adapter changes.
- Bench tested on actual hardware: We cycled this cell through full charge and discharge passes on the S5 Plus body. The BMS accepted the cell without rejection flags, held the charge curve within spec, and triggered the low-voltage cutoff at the correct threshold.
- First-cycle initialisation on the S5 Plus: After fitting this cell, run one complete charge cycle through the camera body before heavy recording sessions. The S5 Plus BMS maps its battery-remaining display against the first full charge curve it sees — skipping this step can cause the indicator to read inaccurately until the next full cycle.
Why the S5 Plus battery indicator reads full then drops suddenly
The S5 Plus uses a voltage-threshold method to estimate remaining charge rather than a coulomb-counting circuit. A new replacement cell has a slightly different discharge curve shape compared to the original OEM cell the firmware was calibrated against. This causes the indicator to hold at a high reading longer than expected, then step down sharply as voltage drops through the steeper part of the curve. One full charge-discharge cycle through the camera body lets the BMS re-anchor its thresholds to the new cell's actual curve.
S5 Plus not recognising the replacement cell on first install
Some S5 Plus units display a no-battery or unresponsive state when a new cell is fitted cold, particularly if the replacement cell shipped at a low storage charge. The BMS requires a minimum voltage at the cell terminals before it will initialise — if the resting voltage sits below that floor, the camera will not boot. Connect the camera to its OEM charger immediately after fitting the cell and allow it to charge for at least 15 minutes before attempting to power it on. If the camera still does not respond, confirm the cell terminals are making clean contact and that the connector is fully seated.