100A Solar Charge Controller，Solar Panel Battery Intelligent Regulator with Dual USB Port 12V/24V PWM Auto Paremeter Adjustable and a USB Male to Female Extension Cable, BLACK

Set up with 100w solar panel to maintain batteries inside remote barn. First setup used wire too small and the 14.4V upper limit was hit quickly and unit dropped to float voltage. Replaced 24ga with 12 ga and it now works great. Instructions are easy and unit is easy to read. Contacts are small and 12 ga wire fills them up. Would not work with any wire larger than 8 ga. Be sure to look at current and voltage drop in your conductors when planing system . Distance between controller and batteries is a major factor on voltage at load. I am using power cords for outdoor sprinkler/lighting systems with 3” alligator clips. Spare battery, under the controller, is used as constant load while leads are moved between tractors and other equipment in barn. Controller reacts to line voltage and not load so all the batteries , in parallel, get similar voltage that drops at battery that is drawing most current. Having all the batteries charged helps them when cold weather sets in.