Advances in off-grid solar power make it possible to power homes and businesses without connecting to public utilities, making solar arrays vital to those seeking to live more sustainable, independent lives. The process isn’t easy and requires a significant investment of time and money, but the results are well worth the effort. 
Why Do You Want to Live Off-Grid?
Before we delve into the intricacies of going off-grid with solar power, it’s important to understand why you want to go off-grid in the first place. Public utilities are, after all, good deals for their monthly fees and, despite blackouts and rolling brownouts, pretty reliable. So why switch to off-grid? Possible answers to this question include:

• Your home or business is geographically far-removed from the grid
• You want to live a more sustainable, greener life
• You want to eliminate your vulnerability to power outages
• You prefer to take personal responsibility for your own power
• You want to remain connected to the grid but reduce your reliance on it.

More than one of these answers may apply to your situation, or you may have your own reasons not listed here. For the moment, however, let’s consider the last answer on our list. 
Going Off-Grid Without Going Off-Grid
People interested in solar power aren’t always planning on going completely off-grid. In many cases, they’re looking for a renewable energy source to offset their utility bills.
Using solar power in combination with energy from the grid makes sense for many businesses and residents. Solar power is used to cut utility costs. The Majority of states offer some type of net metering system so you can transfer excess power from your solar system into the grid for credits on your bill, allowing you to save money when solar power output drops.
Grid-tied solar systems aren’t for everyone. Most such systems don’t have built-in batteries, so don’t provide protection during blackouts. They do, however, offer less cost, are easier to install, and have lower maintenance requirements and higher system lives than completely off-grid systems.
Battery-based grid-tied systems are perhaps ideal, as your system offers both renewable energy and stored power for during outages. Many businesses use such systems to protect mission-critical equipment from power interruptions. 
Going Off-Grid
If grid-tied systems are not feasible—or if you want complete energy independence on principle—you’re going to want to take advantage of off-grid solar power and other renewable energy sources.
There’s a romance attached to going off-grid because of the independence such systems offer. Do not let idealized notions cloud your judgement. Going off-grid successfully means being realistic about the amount of energy your system produces and the energy you use. System costs, maintenance, and time constraints are also important considerations, but let’s start with load analysis. 
Load Analysis
Understanding how much energy you use is vital information for anyone wanting to design an off-grid power system. Your energy load (the amount of energy your home or business uses) is measured in kilowatt-hours, or kWh. You’re going to need an accurate measurement of your month-to-month energy load before designing your system.
If you’re on the grid, measuring your energy load is as easy as reviewing your last twelve months of electric bills—your kWh consumption for the month is listed on each bill. It’s important to note how energy loads change over the year; a solar system capable of handling the energy load of a North Dakota dwelling in July might not be able to provide enough power in mid-January.
If you’re already living off-grid, you’ll need to measure the wattage and daily kWH use of every load in the building. Commercial meters such as Kill A Watt are helpful for measuring 120 VAC loads, while 240 VAC loads can be measured with kWh meters designed for utility use. 
Reducing Energy Load
If your energy load is higher than an off-grid solar system can handle, you need to find ways to reduce the load. Common sense energy efficiency tips can reduce the average household’s energy load by up to twenty percent, although with a dedicated approach to energy consumption it’s possible to cut load as much as fifty percent. Possible strategies include: 
Choosing Energy Star high-efficiency appliances
Controlling phantom loads by prewiring switched outlets to cut power completely when not in use
Using compact florescent and LED lightbulbs

• Choosing front-loading clothes washers which use less power than vertical-loading models
• Go solar for clothes drying (Grandma called it a clothesline!)
• Use laptops instead of CPUs
• Wood stoves
• Passive solar water heaters
• Use portable generators with solar panels to recharge and use small appliances. 

Measuring Sunlight
The effectiveness of any off-grid solar system, from small portable generators to large systems, depends on how much sunlight your location receives. Online data should provide you with your regional average, but this may not accurately affect the microenvironment in which your system will operate. Shade analysis tools, such as Solar Pathfinder, help measure how much energy you can expect to capture with your system.
Don’t neglect other types of renewable energy. Backup Lithium batteries can capture power from wind turbines as well as solar arrays, and you may be able to incorporate hydropower if local streams provide the right conditions. 
System Components
The two main components for your system will be your solar array and your storage battery (or batteries). Solar arrays are long-lasting: you can expect anywhere from thirty to fifty years use from them. Batteries will not last as long, although the technology behind solar storage is increasing all the time.
Misusing a battery will seriously compromise its life, sometimes to as little as a few years. For this reason, consider starting with less costly batteries and upgrading as you learn proper battery maintenance.
Your system will also require some form of generator, for times when solar power proved insufficient for your needs. Portable generators are fine for small tasks, but a larger fuel-based generator may be needed as a backup for large solar systems. 
Installation Options
Off-grid life tends to attract individuals who value independence, so you may be tempted to build and install your solar system yourself. This is possible, but unless you’re willing to commit to some intensive training and education (plus the possibility of costly errors) you might be better off hiring a contractor for installation.
Be aware that most solar contractors are familiar with grid-tied systems with no battery component. You may have to search to find one with completely off-grid experience. The extra effort is well worth the time.
Unlike grid-tied systems, once you’re off-grid your energy production is entirely in your hands. Some find this challenge refreshing, while other people find the commitment too much to handle. If you’re truly committed to independent, sustainable living however, off-grid solar helps you meet your goals. 

Source: http://www.wisefoodstorage.com/blog/going-off-grid-solar-power/