Note:It is high quality compatible MPPT + PWM Solar Controllers ,not 100% Ture MPPT The controller is 12/24/36/48V auto, the voltage of the photovoltaic panels used to charge different batteries is different. For 12V batteries, use about 18V photovoltaic panels, for 24v batteries, use about 30-37V photovoltaic panels, and for 48V batteries use 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 cause damage to the controller 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 connect the battery to the controller first, and then the photovoltaic panel to that 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 cause voltage Identification error. Colour:black Material:plastic type: 100A Package Contents: 1 x Solar MPPT Controller Only the above package content, other are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.