You must note that this product is only a charger (not a starter, so there is no startup function). Before using the product, you must pay attention to the correct installation of the positive and negative poles, and follow the operating methods. How to use: Before charging: Check your battery parameters is compatible to the charger. When charging: 1.Connect the red clamp to the positive pole (+), black clamp to the negative pole (-). 2.Connect the charger with AC power source, the charger will start to operate. 3.Once the battery is fully charged, the battery bar on screen will in “FUL” status. Charging completed: Keep the charged status in 1-2 hours is highly recommended, Then, remove the charger.