The first step in designing a system is usually the most difficult. You need to accurately determine the loads in watt-hours. That means you need to know the power (watts) each piece of equipment uses and how many hours a day it will be turned on. (watts x hours = watt-hours) Batteries and solar panels will be sized based on the watt-hours per day you need, and the inverter is sized based on the peak watts needed by your equipment.
Click on the photos below for design help for each of the system components.
Panels are sized based on the daily watt-hour needs of your loads, but panels are rated in watts, not watt-hours. Depending on your weather conditions expect a panel rated 100W to generate 400 to 500 Watt-hours each day.
Fuses provide safety from shorts & overloads; breakers do the same but can also serve as manual disconnects for maintenance. You should have one on the wires to the panels and another on the wires to the battery. Make sure your breakers and fuses are rated for DC. AC breakers may not be able to stop DC current when they trip.
The Charge Controller goes between the panels and the battery and protects the battery from overcharging. They are rated in Amps. Divide the watt rating of your panels by the voltage of your battery to calculate the charge controller amps.
The inverter produces the high AC Voltage your equipment expects. It is rated in watts, and is sized according to the maximum wattage of all the loads that will be connected at the same time. Usually about double the watts of your “normal” load is about right.
Batteries are your biggest long term expense. They can cost more than fuel for a generator would cost. Choose wisely and care for them properly to save money.
Often ovelooked, a Low Voltage disconnect saves you money by guaranteeing you never ever, not even once, run your batteries down too low, which kills them off early.