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."