Energy efficiency is essential no matter what your power source but even more so if you have an off-grid solar system. You must consider all aspects of the installation from its setup to real-time use. Many things are common sense, such as lowering your thermostat at night. Others aren’t as obvious but can drain your pocketbook if you’re not careful.
Your system will include four components: solar or PV panels, a charge controller, a battery bank, and an inverter. Other parts will vary based on the design of your setup and energy needs. Let’s do a deep dive into an off-grid solar system and how you can use it wisely.
Preparation for Going Solar
This type of setup requires planning if you want to go off the grid. Installing solar panels is only the first step. You also must safeguard your system from things like reverse currents to keep the juice flowing to your home.
1. Do Your Homework Before You Start Your Installation
They say that those who fail to plan, plan to fail. Nothing could be truer when discussing an off-grid solar system.
Check with your local utility company before you start. Find out what regulations you must follow to avoid a costly fix down the line. Don’t think you can slip anything by because you will get caught sooner or later. A simple call can determine what permits you need and any specifications about the components.
Then, there is your off-grid solar system diagram. Plan everything out on graph paper before investing any money in components. Measure once and then do it again. Note where you’d like to install everything to avoid any nasty surprises. Pay attention to any specific requirements like spacing distances. It’s the single best way to avoid any unnecessary delays in going solar.
Do the math. Find out how much power you need with a range to accommodate different scenarios, such as guests visiting or inclement weather calling for a greater demand on your energy capacity. Also, take into account the energy use of the equipment of your system, such as the inverter.
You’ll find the energy demands in watts per hour of your appliances either on the label on the back of the device or the manual. They will use the most electricity, so determining a figure for them puts you in the ballpark. For lighting, you can plan on about 876 kWh per 100-watt incandescent light bulb or 140 kWh per 16-watt LED per year, assuming 24/7 use.
A quick way to get your daily usage is to check your past utility bills. You’ll see a monthly figure which you can then divide by 30 to get the use per day. Then, multiply it by 1,000 to convert it to watt-hours. You’ll need that number to decide what kind of system you should get. Ideally, you’ll have more than one year of history to check for a more realistic picture of your home’s energy use.
Check this out if you are interested in solar kits for tiny homes.
Getting Figures for Your Setup
Planning is imperative when determining what you need for batteries and solar panels. Again, it’s essential to do the calculations upfront. It will also help you determine your ROI for setting a budget on your off-grid solar system. You can figure on paying anywhere from $5,000 to well over $20,000, depending on the size of your house and energy needs.
2. Figure Out What You’ll Need for a Battery Backup Bank
Ideally, you live someplace where your solar panels receive the maximum amount of direct sunlight for peak performance. Your battery bank will keep you off the grid during days when it’s overcast or raining. However, you must have an adequate backup system in place. Err on the side of caution and plan on at least five days or even more if you live in the Upper Midwest or on the East Coast.
The typical American household uses about 914 kWh of electricity per month or around 30 kWh per day. That’s when the utility company manages your energy use. With an off-grid system, you must also consider the impact of temperature on your batteries, along with the energy loss from discharging your backup and operating an inverter. All these things add up and can affect their performance.
A safe estimate is to double your per day usage to account for everything to run your household off the grid for one day. That will cover the inefficiencies of the different components of your system and other things that can put a draw on the power. Your watt-hour calculation is only the start.
Your usage may vary, of course. That’s why it’s essential to begin with the typical scenario in your home and go from there. Base your decision on the minimum number of sun hours that your area receives during January since that’s when you’ll need to rely on battery power the most. You can get this information from the National Renewable Energy Laboratory (NREL).
We suggest considering the lowest temperature that your area typically experiences when calculating your battery bank size and its effects on discharging. Lower temperatures will drain a lead-acid one quicker than a setup in a warmer place. Also, go bigger instead of smaller when it comes to your battery bank to keep the number to a minimum.
3. Determine the Number of PV Panels You Must Have
The business end of your setup will keep your batteries charged and ready to fill in on cloudy days. You can find out what you need by taking your daily energy needs and dividing it by the minimum number of sun hours for your area. That will give you the estimated array size for your solar panels. Coupled with your desired battery bank size, you can figure out your setup options.
For example, if your array size is 1400 watts with a 4800 watt-hour back-up capacity, then you have three choices for a battery based on its voltage: 400 Ah at 12 Vdc; 200 Ah at 24 Vdc; or 100 Ah at 48 Vdc. You can then determine which one is best for you based on your budget. Bigger is better, as we’ll discuss later.
The NREL also has a PV Watts Calculator tool that can provide specific data on your annual energy costs based on the average monthly solar radiation and type of off-grid solar system. It’ll provide specific information that your service rep can use during the installation.
An off-grid solar system isn’t perfect. Solar power itself isn’t the most efficient energy source. That’s why you need to account for the inherent inefficiencies in your final equation. Even a small number could have a significant impact. We recommend going conservative and adding some wiggle room when deciding on the various components.
Learn how to Calculate Watt Hours!
So, you’ve seen the term Watt Hour pop up a lot lately. You may have been wondering what it is and how to calculate them? In this blog post, we will talk about what a Watt hour is, and how to calculate them.
Learn about solar panel angles and what angle is best
The angle that your solar panels are facing is important in order to maximize the amount of energy they produce. There are a lot of factors that go into determining which angle should be best for you, but some general guidelines can help simplify things.
The wiring of your system is critical to keep it running efficiently. Other parts can give you more control over its operation and, thus, your energy savings. It allows you to put in safeguards to ensure that you always have power. You’ll also find more ways to save money and get the most out of your investment.
4. Opt for the Higher Capacity Battery If You Have That Choice With the Other Necessary Parts
Using a 24 or 48 Vdc battery will allow you to reduce the number of parallel strings, and thus, keep your cost in line. It will also provide additional protection against reverse currents that can take out your system. It’ll mean less wiring, which can add up to some significant savings. Fewer parts also are fewer things that can go wrong.
An inverter takes the DC energy that your battery holds and converts it to AC for use in your home. The two components must match in voltage capacity. One for 12 volts won’t work with a 48-volt battery back. It’s another reason that we strongly urge you to plan with your future needs in mind. Look for one that matches the total load of your system in watt-hours plus a 20 percent margin for error.
Your batteries are one of the most expensive parts of your system. Therefore, anything you can do to extend their lifespan is a wise move. You must pay closer attention to power management if you have lead-acid batteries. That’s where a solar charge controller comes into the picture. It will make sure that your battery bank isn’t overcharged, and that charging happens consistently.
Choose a device with about a 20 percent higher rating to play it safe. If you have a 12 Vdc system, go with a product that is 15 Ah. You’ll see two types on the market, MPPT or PWM. The former is the more efficient of the two and will allow you to get the maximum power from your solar panel array. However, it is more expensive than the PWM type, which is more appropriate for smaller systems.
Installation and Usage
Installing a solar system is a daunting task because of the complexity of the technology. That’s why you should only have a trained professional take on this project. They can ensure that everything is up to code and help you with getting the necessary permits.
5. Check Out Any Available Incentives Before You Commit to a System, Along With More Than One Estimate on Your Installation
It’s an excellent time to invest in solar power with a wide range of rebates, incentives, and other perks associated with making the move to renewable energy. Make sure to find out which ones you can get before buying. Some may have specific conditions and time periods for which they are valid. The Solar Energy Industries Association maintains a current list by state.
Fortunately, the components of a solar-powered system have decreased in recent years, making it a more affordable option. With your usage figures in hand, we’d recommend getting more than one estimate on your project. The industry is evolving rapidly with advances in technology and more efficient equipment. Considering the investment you’re making, it only makes sense to explore your options.
Make sure that you get an itemized estimate with essential specs like ampere-hours and watt-hours. That will make it easier for you to do a comparison.
6. Avoid Package Deals and Read the Terms of the Warranty Carefully
You’ll often see installation bundles that include the major components of an off-grid system. However, it’s often better to buy the parts separately since the deal isn’t always the most efficient and ideal for your situation. Doing so gives you the opportunity to customize your setup for what you need now and in the future.
Only buy solar panels that include a warranty. Things go wrong, so you must ensure that you’re covered. The chances are that it’s going to take 10 or more years for you to recoup the cost of your investment. We suggest getting a product with a warranty for at least that time. And always read the small print. You’ll likely see terms such as annual maintenance or certification of service reps to keep it valid.
Make sure to document everything as it pertains to the terms of the warranty. That will protect you if you have to make a claim. Keep your original invoice too, just in case.
7. Make Your PV Panels Accessible and Put a Battery Monitor in Your Home
Do yourself a huge favor and have your solar panels installed where you can get to them easily, if possible. Remember that you’ll need to clean them off every time it snows. That’s especially important if you live in a colder part of the country. It’s also a smart idea for the routine maintenance that your system will require. Your service rep will thank you.
A battery monitor is a handy device provides vital information about the status of your battery bank. It can help you stay on top of maintenance and alert you to possible problems with your system. All of these data are critical, especially when you first make the move to going off the grid. It’ll allow you to keep track of your accumulated amp-hours for monitoring your household’s energy use.
Tips for Improving Energy Efficiency
The point of going off the grid is to lower your carbon footprint and save money. It only makes sense to get the most out of your off-grid solar system by ensuring that it’s running at peak efficiency. That means considering the entire setup, including the things that it’s meant to power. But that’s only the tip of the iceberg.
8. Make the Move to LEDs and More Efficient Appliances
The last thing you want with an off-grid solar system is to waste energy needlessly. That is exactly the result if you don’t make the move from incandescent to LED light bulbs. Upward of 90 percent of the energy the former type receives goes toward heating them. We’d suggest skipping the CFLs because of the risk of handling them. Instead, go for the best option with the best ROI.
If you’ve done your homework, you know which appliances are the energy hogs. Save yourself some cash and replace the high-capacity ones with something that is more efficient, preferably an Energy Star model. Even if you have to pay up, you’ll benefit in the long run. After all, using an off-grid solar system is all about the numbers and energy efficiency.
You can increase the efficiency of your system by running some devices directly from a battery. It will allow you to bypass the inverter, a significant source of energy loss. You’ll save even more if you can use DC power for things that you need to run continuously, like your refrigerator or freezer. While you may find that they are more expensive up front, they will pay for themselves over time.
9. Get the Most Out of Your Installation
While you’re switching to solar, it’s also a wise plan to look at your insulation and upgrade it if necessary. You may find that you can get an additional rebate or incentive by making your home even more energy-efficient. Also, check for leaks around your windows and doors. Seal any that you find. We are big fans of placing plastic over your windows during the winter months too.
You’re likely aware of how utility companies meter usage differently, based on consumer demand. Using appliances like your washing machine during peak hours costs you more. The same type of scenario exists with an off-grid solar system without the added price.
You should use these devices when your PV panels are actively capturing solar energy to ensure that your batteries stay fully charged. That way, you can save the energy they hold for evenings and overcast days.
10. Keep Up With the Maintenance of Your Batteries
Your battery bank will require some care to get the maximum life out of it. That means topping off lead-acid ones with distilled water occasionally. You should also make sure that all get charged. If you have multiple ones, switch out their position now and then so that all are getting adequate use.
We’d also suggest opting for bigger interconnect cables, which can help them operate more efficiently by reducing resistance. Finally, do not let the depth of discharge (DOD) go below 50 percent. Doing so can reduce its lifespan significantly.
11. Stay Current With the Technology, Including Getting a Backup Generator, Just in Case
You don’t have to delve too far in the solar power technology to realize that it’s in flux. You only have to look at how the prices have dropped in recent years to know that things are changing. That’s good for you because it means that you’ll get a better value for your money.
We’d also say to stay flexible with your system to take advantage of advances as they happen. After all, an off-grid solar system is a work-in-progress.
One reason that people make the move to go off the grid is the freedom to power their homes in the way they want. Unfortunately, nothing is infallible—including an off-grid solar system. The weather adds an unpredictable element to the mix that you shouldn’t ignore. That’s why we strongly urge you to get a backup generator as part of your installation.
Then, you can rest assured that you’ll always have a reliable power source. It’s also a smart idea for routine maintenance or if you have to replace a part. Another option is to supplement your solar power with a wind turbine. It’s an excellent idea if you like in an area with a lower solar radiation capacity but still want the benefits of using renewable energy.
Connect with others living off the grid. You’ll find plenty of company when you make the move to an off-grid system. In many ways, it’s a lifestyle with far-reaching effects that extend to other eco-friendly activities like gardening, composting, and recycling. Networking with others in your mindset will give you a chance to share tips and advice about using solar and increasing its efficiency.
Final Thoughts About Setting Up an Off-Grid Solar System
Going off the grid is an excellent way to take control of your energy needs that puts you in charge. You control your costs by managing the installation and the components of the system. The essential thing to remember is that your household must be smart about its electricity usage to make the most of your investment. After all, that’s likely one reason you’ve made the decision to go solar, anyway.
The best way to get the most out of your off-grid solar system is to do your homework upfront before you buy it. Determine the energy needs of your household with the appropriate margin for error to make sure you’re getting something big enough that is in line with your expectations of how it will perform. Careful planning will ensure many happy years of renewable energy.