Avant S8 BATS8 Replacement Battery 3.7V 1250mAh Li-ion

Avant S8 / S10 Series — 3.7V Li-ion Replacement Battery (BATS8)

This is a 3.7V, 1250mAh Li-ion cell that replaces the BATS8 battery in Avant S8, S8x6, S10, and S10x6 digital cameras. It slots into the same battery compartment as the original and connects via the same contact arrangement. Capacity matches the OEM spec at 4.63Wh.

• S8, S8x6, S10, S10x6 compatibility: All four models share the same battery form factor, voltage rail, and BMS communication protocol — one cell covers the entire range without modification.
• Bench tested on actual hardware: We cycled this cell through the camera's onboard charger and monitored BMS acceptance, charge termination voltage, and discharge curve across multiple cycles. The BMS accepted the cell without fault flags on each run.
• First-cycle charge protocol for the S8 body: Run the first full charge inside the camera body or OEM charger — not a third-party USB adapter. Some Avant camera BMS systems only map the battery-remaining indicator correctly after completing one full charge cycle through their own charge circuit.

Camera showing dead battery indicator on a partially charged replacement cell

The Avant S8's battery gauge maps percentage thresholds against a specific discharge curve. A new third-party cell can have a slightly different internal resistance profile, which causes the indicator to read low or show empty when real charge remains. This is a calibration mismatch, not a fault with the cell. Running one or two full charge-discharge cycles through the camera body lets the BMS re-map its thresholds to the new cell's actual curve.

Battery percentage jumping erratically mid-shoot

When the S8 is firing the flash repeatedly, the capacitor recharge current spikes draw hard against the cell. If the replacement cell is cold or has not yet been fully cycled, its internal resistance is higher than the BMS expects — causing the voltage to sag briefly and the indicator to jump down then recover. Let the battery reach room temperature before shooting, and complete at least one full charge cycle first. After conditioning, the indicator should stabilise above 3.6V under load.