As the most high-end and advanced solar controller it charges the battery with the max power MPPT tracking efficiency is 99% and the whole system has a high power efficiency of 97%. Features: This product provides short-circuit protection open-circuit protection reverse protection overload protection. 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 the battery with the maximum power. The tracking efficiency of MPPT is 99% and the power 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: /24V Auto Adapt Material: ROHS+ABS Item color: blue+black 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 does not work ? Why is it less than 100A? 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.