Note:It is high quality MPPT + PWM Solar Controllers ,not 100% Ture MPPT The controller is 12/24/36/48V auto, but the voltage of the photovoltaic panels used to charge different batteries is different. For 12V batteries, about 18V photovoltaic panels, for 24v batteries, about 30-37V photovoltaic panels, and for 48V batteries 60. For photovoltaic panels around -72V, the controller wiring is connected to the battery first, and then to the photovoltaic panel. Disconnect the wire on the contrary, otherwise it will easily damage to the controller! ! ! Description of charging protection When using a 12V battery, the boost charging voltage of the battery is higher than 14.8V, and it is converted to a floating charging voltage of 13.8V. When using a 24V battery, the battery boost charging voltage is higher than 29.6V, and it changes to a float charging voltage of 27.6V. When using a 36V battery, the battery boost charging voltage is higher than 44.4V, and it changes to a floating charging voltage of 41.4V. When using a 48V battery, the battery boost charging voltage is higher than 59.2V, and it changes to a floating charging voltage of 55.2V. Note: Please the battery to the controller first, and then the photovoltaic panel to the battery voltage is higher than (12V battery is higher than 10V; 24V battery is higher than 20V; 36V battery is higher than 30V; 48V battery is higher than 40V), otherwise it will voltage Identification error. Colour:black Material:plastic type: 100A Package Contents: 1 x Solar MPPT Controller Only the above package content, other products are not included. Note: Light and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.