Solar Charger Controller 10A: if your battery is 12V, the max solar panel input is 25V 120W if your battery is 24V, the max solar panel input is 50V 240W 20A: if your battery is 12V, the max solar panel input is 25V 240W if your battery is 24V, the max solar panel input is 50V 480W 30A if your battery is 12V, the max solar panel input is 25V 360W if your battery is 24V, the max solar panel input is 50V 720W If you though 30A is too small, you can buy 60A, one is with wifi function, another is without. Features: 1.Build-in industrial micro controller. 2.Big LCD display,all adjustable parameter. 3.Fully 4-stage PWM charge management. 4.Build-in short-circuit protection,open-circuit protection,reverse protection,over-load protection. 5.Dual mosfet Reverse current protection, low heat production.