As the most high-end and advanced solar charge controller, it charges the battery with the max power, MPPT tracking efficiency is 99%, and the whole system has a high power generation efficiency of 97%. Features: This product provides short-circuit conservation,open-circuit conservation, reverse conservation, overload conservation. Automatic focusing MPPT tracking charging, high charging efficiency, non-stop detection during charging, bidirectional focusing tracking. MPPT solar controller can detect the voltage and current of the solar panel in real time, and constantly track the maximum power, so that the system can always charge the battery with the maximum power. The tracking efficiency of MPPT is 99%, and the power generation efficiency of the whole system is up to 97%. Moreover, the system has excellent battery management, including MPPT charging, constant voltage average charging and constant voltage float charging. Specifications: Battery voltage: 12V/24V Auto Adapt Material: ROHS+ABS Item color: blue+black Charge current: 30A, 40A, 50A, 60A, 100A (optional) USB output: 5V 2A Item size: 170 * 95 * 40 mm / 6.69 * 3.74 * 1.57 in Item weight: 260 g / 9.17 ounce Package size: 175 * 100 * 45 mm / 6.89 * 3.94 * 1.77 in Package weight: 295 g / 10.41 ounce Notes: 1. What is MPPT? Automatic load tracking aggregation. 2. Why "Only works with the battery connected, turn on the solar panel charges the battery, charge does not work"?Why is it less than 100A? We are a current-focus MPPT with two constantan wires designed to detect current and maximum open-load when more 1A.This technology is our patent practice, and has been recognized by the state, with a special patent certificate of invention.There is no such technology on the market. Compared with other MPPT MPPT-inductive buck-boost type, the same solar charging condition, our current-focusing MPPT current tracking efficiency is higher, because of the power loss caused by the booster and the step by step down. In fact, the effectiveness of very low light charging is very low because the input power is very small.