As the most advanced and advanced solar charge controller, it charges the battery with maximum power, the MPPT tracking efficiency is 99%, and the whole system has a high power generation efficiency of 97%. Functions: This product provides short circuit protection, short circuit protection, reverse protection, overload protection. Automatic focusing MPPT tracking charging, high charging efficiency, continuous detection while charging, bi-directional tracking focus. The MPPT solar controller can detect the voltage and current of the solar panel in real time, and keep track of the maximum power continuously, so that the system can always charge the battery with maximum power. The tracking efficiency of MPPT is 99% and the energy generation efficiency of the whole system is up to 97%. In addition, the system has excellent battery management including MPPT charging, DC medium voltage charging and constant voltage trickle charge. Specifications: Battery voltage: 12V / 24V Auto Adapt Material: ROHS and ABS Item Color: Blue and Black Charging current: 30A USB output: 5V 2A. Item Size: 170 x 95 x 40mm / 6.69 x 3.74 x 1.57in Item Weight: 260g / 9.17oz Package weight: 295 g / 10.41 oz Package List: 1 x Solar Charge Controller 1. what is MPPT? Aggregation of automatic load tracking. 2. Why "Only works with the battery connected, turn on the solar panel is charging the battery, charging is not working"? Why is it less than 100 A? We are an MPPT focusing on currents with two Constantan conductors designed to detect the current and the maximum open load when more than 1A. This technology is our patent practice and has been recognized by the state with special invention patent certificate. such technology on the market. Compared with other MPPT-inductive buck-boost types, the same solar charging condition, our MPPT current tracking performance focusing on current is higher due to the power loss caused by the amplifier and step-down. In fact, the charging efficiency in very low light is very low as the power input is very low. Our MPPT can also increase the load in relatively low light. Our MPPT is simple type. When the current is greater than 1A, it will not be tested. The chain will be loaded directly. Only when it is charged to 95% of the battery does it slow down and protect the battery.