Note:It is high quality compatible 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, 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 easily cause 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 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 cause voltage Identification error. Colour:black Material:plastic type: 100A Package Contents: 3 x Solar MPPT Controller Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.