What is an off-grid solar system? While many people think only of solar panels when they hear “off-grid solar”, the reality is that you need to add many other components to get a functioning off-grid PV system.   A complete off-grid solar system is one that has all the necessary equipment to generate, store, and supply solar energy onsite. As off-grid solar systems operate without a connection to any external power source, they are also referred to as “standalone solar power systems”. Unlike other types of solar setups, such as the more common grid-tied solar system, off-grid solar systems rely on batteries to provide power when the sun isn’t available. Batteries, however, are costly — much more so than the solar panels they are paired with. The need for ample battery storage in off-grid solar systems makes them much more expensive than grid-tied solar systems.  What are the different uses of off-grid solar power? One of the biggest advantages of solar as an energy source is its scalability and modularity, which is the degree to which a system’s components may be separated and recombined for flexibility and variety in use. It works at all levels, from small devices such as solar phone chargers, all the way up to a system that can power a factory. Here are some of the most common applications of off-grid solar: • Providing a charge to a portable phone or tablet charger • Powering the appliances in an RV • Generating electricity for small cabins • Powering small energy-efficient homes It’s worth noting where off-grid solar systems do NOT make sense: where there is easy access to the utility power. This covers situations where one is looking to power a home in a home in a city, suburb or town. If that’s you, you can save much more by opting for a grid-tied or hybrid solar panel system — or even just sticking solely to grid power — depending on the economics of solar in your area. What equipment does an off-grid solar system require? Here’s a list of all the equipment required for a functioning off-grid solar system: • Solar panels • Solar charge controller • Solar inverter(s) • Solar battery • Mounting and racking system • Wiring • Junction boxes How to size an off-grid solar system Deciding on the size of the system you need is an early and absolutely crucial step when it comes to installing an off-grid solar system. It will affect the kind of equipment you need, how much work the installation will involve, and, of course, the total cost of the project. Solar setup sizes are based on the amount of power the system needs to provide. There are two different ways to figure out the number you need, and they are based on:  • Your current usage • Load evaluation Basing solar setup size on usage You can use this option if your aim is to maintain your current lifestyle as you switch from grid-tied to off-grid solar. To do this, you can simply refer to your monthly power bills to determine your electricity usage in kilowatt hours. You can then size an off-grid system of that size, although you’d want to go a bit bigger — say 10% more — to allow for solar inefficiencies.  Basing solar setup size on load evaluation The second option is to perform a complete load evaluation to determine how much power you’ll need. 1.  Calculate total electricity usage needs o Begin by listing out all the appliances you plan to use, and how many hours you’ll be using each of them. This allows you to calculate the power consumption of each appliance, as well as your total power consumption over a day. o Knowing how many kWh in a day you’ll use will allow you to size your solar panel array, as well the solar battery storage. 2. Calculate instantaneous load requirements o You’ll also have to calculate how many appliances you might run simultaneously. This will help you calculate instantaneous wattage requirements, which you need to know in order to size the inverter properly (the inverter runs the AC loads). 3. Decide on battery storage capacity o Next, you’ll need to decide how much energy storage you want. Do you want to cover usage for just one day, or do you want to have extra backup capacity? o When it comes to solar battery backup, the rule generally is you'd want enough storage to cover at least 2-3 days of usage during the highest usage time of year. 4. Design a system around your number from Steps 1-3 o Figuring out the sizes of these three crucial components — the solar panels, inverter, and battery storage — is usually enough information for solar equipment vendors to customize a complete off-grid kit for you.