Off-Grid Solar Power
Powering your home off-grid can be a big undertaking, knowing where to start can make all the difference. In the industry we have a saying It is cheaper to conserve than to create when it comes to powering homes off-grid. So, knowing your power needs will be a good place to start.
Planning Required for Off-Grid Battery Based Systems
The first step in planning your off-grid system is to figure out how many watts of power you need per day. Once you determine what you are trying to run, and how long each day you want to run the items, the first place you have to start, after reducing your loads, is to determine your daily energy budge or daily loads. You are going to want to reduce your daily energy demands first before you start to calculate your loads because it is cheaper to save energy than to make energy. The trick to off-grid living is energy conservation and efficiency. The starting point in planning your system is to first reduce demand.
What's the difference between watts and watt hours?
Watt and watt hours are often misused and misunderstood. A watt (W) is a measurement of power which is the rate of electricity that is being generated or consumed. A watt hour (wh) is the same energy over a period of time. A light bulb rated at 60 watts, in 1 hour it will consume 60 wh of energy, and in 3 hours the same light bulb will consume 180 wh of energy.
Solar Panel FAQ
System Voltage and Batter Bank Voltage?
In DC systems voltage is determined by the battery bank of the off-grid system. The primary factor in making this decision will be how much power you require from your batteries. As power demands increase you should raise the battery voltage, 1) because of less resistance and 2) you should not put more than 2 battery banks in parallel and never more than 3 on one charge controller.
How Many Solar Panels are Needed?
Number of Solar Panels = Daily Watt Requirement (1 - 24 hour period (Energy Budget)) + 48% (Derate Factor) ÷ shortest day sun hours ÷ panel STC rating = number of solar panels needed.
How Many and What Size Batteries?
Battery bank sizing is the part of the system that is most likely to cause you problems if not done properly. Your budget may tempt you to consider cheaper battery alternatives but a quality battery will pay off over time. We recommend a 2VDC or 6VDC battery and connect them in series to get the total DC voltage needed for your system voltage. Do NOT put more than 3 strings of batteries on one charge controller.
There are many other factors that need to be considered to put together a successful off-grid system. These systems are a considerable investment and should be designed by a professional who understands many factors that go into off-grid power.