How much sunlight is required to maximize the battery extension on the Garmin Fenix 8 Solar

- In smartwatch mode, the Fenix 8 Solar can last up to 30 days without solar charging. With sufficient sunlight exposure, this can be extended to 48 days[1][2].

- In GPS mode, the Fenix 8 Solar can operate for up to 95 days. With solar assistance under optimal conditions, this can reach 149 days[1].

However, the exact amount of sunlight required to achieve these extended battery life estimates is not specified. Factors like cloud cover, time of day, and the watch's orientation to the sun likely impact the solar charging efficiency and battery life.

Garmin's official documentation states that the solar charging lens on the Fenix 8 Solar captures sunlight to recharge the battery, allowing the watch to extend its battery life when exposed to ample sunlight during outdoor activities[1]. But the specific lux levels or hours of direct sunlight needed are not provided.

In summary, while the Garmin Fenix 8 Solar can significantly extend its battery life through solar charging, the exact sunlight requirements to achieve the maximum 48 days in smartwatch mode or 149 days in GPS mode are not clearly defined by Garmin. The watch requires ample sunlight exposure, but the precise amount is not quantified.