As the most high-end and advanced solar charge controller, it charges the battery with the maximum power, the tracking efficiency of MPPT is 99%, and the whole system is at generation efficiency 97% high power. Features: This product provides short circuit protection, open circuit protection, reverse protection, overload protection. MPPT charge tracking auto focus, high charging efficiency, non-stop detection while charging, two-way focus 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 97%. In addition, the system is excellent battery management, including MPPT charging, constant medium voltage charging and constant voltage float charging. Features : Battery Voltage: Car adapter 12V / 24V 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 in Item weight: 260g / 9.17oz 175 * 100 * 45mm / 6.89 * 3.94 * 1.77 Package weight: 295g / 10.41oz Notes: 1. What is MPPT? automatic load tracking aggregation. 2.Why "Only works with battery connected, put battery solar panel loads, charging does not work"? Why is it less than 100A? We are a current tuned MPPT with two constantan wires designed to detect open-at-no-load and maximum when over 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 any other buck-boost type MPPT-inductive MPPT, the same solar charging state, our MPPT current focusing current tracking efficiency is higher, due to the power loss achieved by the booster and step step by step down. In fact, the ultra-low-light charging efficiency 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 it is charged to 95% battery, it will slow down and protect the battery. Package List: 1 * Solar Charge Controller