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 will easily cause damage to the controller of charging protection: 1. 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. 2. 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. 3. 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. 4. 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. Clock setting instructions: When the battery is connected, press "" "" to set the clock table, short press "" to save. Charging voltage setting instructions: After connecting the battery, after setting the clock and saving, long press "" for 3-5 seconds, the screen displays L**V as the floating charge voltage, which can be adjusted by pressing ""; short press again ""H**V is to increase the charging voltage, which can be adjusted by pressing ""; shortly press "" again. F**V is the low-voltage cut-off voltage of the DC load, which can be adjusted by pressing ""; after setting Long press "" for 3-5 seconds to save and exit. Type:100A color:As shown Material:plastic Package Contents: 1x Solar Charge 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.