When using a solar power based charger, such as solar panels you will require some sort of voltage regulator to controller the outputting voltage. This type of voltage regulator is commonly known as a solar charge controller. The size of the system or amount of panels will determine the amperage requirement of the controller. Every solar power home system will require some sort of direct current power reserve, usually in the form of 12 volt or 24 volt battery bank. Therefore you can set your voltage regulator at 12 volts or 24 volts. A full size home electrical panel will be between 50 and 100 amps, you can use this as a guide if you are setting up a complete off grid home system. If you are simply setting up a small backup system to reduce your consumption 5 to 25 amp will be just fine. Without the proper voltage regulator then your power bank and power inverter will not function and you will not be able to power your electrical devices.