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