Go Off-Grid with Solar Power

Explore the components and considerations for creating your own photovoltaic system.

| June/July 2017

red cabin with solar panels

This small building boasts a roof-mounted solar array.

Photo by iStock/Serenethos

If you’re serious about off-grid power, you won’t be surprised to hear that designing for off-grid photovoltaic (PV) systems is a little more complicated than it is for grid-tied systems — but it’s probably still simpler than you think. While the two types of systems have a lot in common, an off-grid system incorporates three extra elements — batteries, a charge controller, and a generator. Although, to counteract this, there are two things that you won’t have to worry about: meters and hassles with the utility company (not to mention utility bills).

Off-Grid Solar Basics

To appreciate the primary difference between off-grid and grid-tied PV systems, imagine you’re planning to take everyone in your household on a long camping trip. One option is to go car camping, where you park your vehicle right at the campsite. You’ll spend your days and nights outdoors, but if you run out of food, beer, toilet paper, or other essentials, you’ll have plenty of backup supplies packed in the car, just a few steps away.

Your other option is a wilderness trip, where you carry everything you need to survive deep into the woods in a backpack. If you plan carefully, and make sure nobody eats or drinks too much, you’ll do just fine. But if supplies run low, you’ll have to cut back on your consumption. And if your supplies run out, they run out. You’re camped too far from the car to hike back, and you didn’t fill it with extra supplies anyway.

You get the idea. Planning an off-grid PV system, like wilderness camping, requires more care and thoughtful examination of what you need on a daily basis. The only thing missing from the comparison, in the off-grid scenario, is a generator for replenishing the energy supply if things get dire. In this instance, you can think of the generator as a fishing pole in our camping metaphor.

It’s a simple matter of supply and demand. Sizing an off-grid system should start with a careful examination of your household electrical demand — your daily electrical loads. (You’ll learn how to calculate loads in “Calculating Loads and Days of Autonomy.”)

Now, let’s take a look at the basic elements of an off-grid PV system.

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