Pleas Note:1. Please charge under STRONG sunlight, do not charge on a cloudy day or place through glass like an indoor window or car door. 2. Solar charging is designed for emergencies, not a primary source of charging due to the compact solar panel size and sunlight intensity, it could take 21 hours under direct strong light to fully charge( assuming there are 7-8 hours of sunlight per day). So we highly recommend charge the solar charger via an adapter or computer, which only take a few hours3.Normally, it can reach 25% battery after 5 hours recharge under strong sunlight, so only the first light will be lit.4. Waterproof in normal everyday conditions.Not designed for underwater use.