As the most highend and advanced solar charge controller, it charges the battery with the maximum power, the MPPT tracking efficiency is 99%, and the whole system has production efficiency. 97?% high power consumption. Specifications: Battery Voltage: 12?V/24?V Auto Adapt Material: ROHS & ABS Item Color: Blue/Black Charging Current: 30?A, 40?A, 50?A, 60?A, 100?A (optional) USB Output: 5V 2A Item Size: 170 * 95 * 40mm / 6.69 * 3.74 * 1.57in Item Weight: 260g / 9.17 ounces Package size: 175 * 100 * 45 mm / 6.89 * 3.94 * 1.77 in Package weight: 295 g / 10.41 ounces Notes?: 1.What is MPPT? Automatic load tracking aggregation. 2.Why Only work with battery connected, turn on solar panel charge battery, charging not work?? Why is it less than 100A? We are a current focusing MPPT with two constantan wires designed to sense current and maximum open load when more than 1A. This technology is our patent practice and has been recognized by the state, with a special invention certificate. such technology on the market. Compared with other types of MPPT inductive buckboost MPPT, the same solar load condition, our currentfocusing MPPT current tracking efficiency is higher, due to the power loss caused by the booster and ramp down. In fact, the efficiency of very low light charging is very low because the input power is very low. And our MPPT can also increase the load under relatively low illumination. Our MPPT is direct type. When the current is over 1A, it will not be tested. The channel will be billed directly. Only when charged to 95% battery will it slow down and protect the battery. Package List: 1 * Solar Charge Controller