The Beginners Guide to Off-Grid Solar
When Chris and I began our journey into the world of resilience and off-grid living, one of the most significant issues we tackled was getting energy on our homestead. We had trials and our fair share of errors, but we managed to create a system that fits our needs. The hardest part in the process was not having a single resource that told us how to go from a solar panel to being able to turn on a light in our home. Sure, tons of resources explain what solar panels are and how to set them up, but a lot of these resources are not geared toward those living on the outskirts of the law.
Electrical codes are on the books to make a safe and healthy environment for inhabitants of a dwelling. The problem some off-grid folks face is not wanting an inspector or agent of the government anywhere near their property. This is where I step in. I am by no means an expert in electrical engineering — but I have had a fully functioning solar-powered house for almost three years. In saying all of that, I'd like to make the following disclaimer:
"I am not an expert in anything electrical. I am showing you how I set up my solar panels easily and safely. I would not recommend anyone follow any of these steps to set up their own off-grid solar array. It would be a shame if you did this, and the government had no idea that you could live off the sun's energy and not pay ridiculous amounts of money to energy conglomerates. Definitely don't follow any of the following steps."
But First, Some Housekeeping
If you are new to the world of electricity, it might be nice to understand some of the terms I will be using in this article. My goal is to make this as painless as possible.
Amp: Amp (A) is short for Ampere. Amps measure the amount of electrical charge flowing past a given point in one second. Simply put, amps measure how much of an electrical current is being drawn through power cables.
Volt: Volts (V), short for voltage, measures how strongly electricity is being pushed through a circuit—the amount of volts tells you the amount of pressure being exerted.
Watt: Watts (W) or wattage measures the amount of electrical power a device uses.
Simple math: W=AxV
The how-to diagram
I spent countless hours scouring the internet, searching for a complete diagram to show how to go from the panels to an outlet. I found some that were mostly good, but none of them gave me all the answers I was seeking. So, for myself and this guide, I created my own. I hope it helps you as you embark on this endeavor.
Step 1: Figuring out your energy consumption needs
The average energy consumption in the "typical" U.S. household is around 10,000kWh a year. That number is entirely ridiculous. If you are serious about taking your life off-grid, you're going to have to lower your energy consumption. Hint: you don't need to have all your lights on simultaneously or during the day at all. Let's say you and your family are energy drainers, and you have to use 10,000kWh a year — you'd be looking at needing 19 (300W) solar panels to run your household under the best conditions. That would run you approximately $6000 (not including tax and all that other shit). If you've got that kind of money, go for it!
Chris and I have 8-300W solar panels that produce 12,000W of power daily with an irradiance of 5 peak sun hours. The panels and battery bank that we have take care of all of our energy needs, and we are probably a little too conservative with the power. I don't like to have more than one light on in the house after the sun goes down (just ask my partner). You have to be careful because you don't want to run into a situation where you run out of power and your batteries deep cycle.
Step 2: Solar Panels
We first started with 3-100W solar panels that we got in a kit from Amazon. They were of decent quality, but they don't draw nearly the amount of power we need for a household. Early last year, we switched to our current system from Grape Solar. You can order sets through Home Depot, which was incredibly convenient for us. Another great company to check out is Renogy. Again, you have to find the panels with the correct wattage for your needs.
Another distinction that should be noted is between polycrystalline and monocrystalline solar panels. When it comes to efficiency, monocrystalline has a higher rating than polycrystalline mainly because it is made of one piece (i.e., mono). As a result, it can withstand higher heat for more extended periods. So do yourself a favor and go with the monocrystalline.
Step 3: Charge Controller
Where do you plug in your panels to produce usable electricity? A solar charge controller. The question is: what size charge controller do you need? Let me hit you with a little bit of math: take the number of panel watts (in our case 2400w) and divide that by the volts of your battery bank (ours is 120v right now, but we will talk about that later). You should then multiply this by 25% to allow for fluctuations from cold temperature and round up. You don't want too few amps for your system, leading to problems. The math looks like this:
2400/120 = 20 | 20x.25 = 5 | 20+5 = 25 amps — to give it a little wiggle room we would go with a 30 amp charge controller. The one that we currently have is the 30A MPPT charge control from EPEVER.
You'll also see PWM and MPPT thrown around when looking at charge controllers. PWM is pulse width modulation, and MPPT is maximum power point tracking. MPPT devices are 30% more efficient than PWM, but they are also more expensive.
Step 4: Batteries
There are so many different types of batteries you could look into when storing the power from your solar panels. The two major styles are lead-acid and lithium-ion.
Flooded Lead-Acid (FLA): These batteries are inexpensive but require a fair amount of maintenance. Each battery cell must be submerged in water, and the water level needs to be maintained regularly, or you will run into unfortunate circumstances.
Sealed Lead-Acid: Similar to the FLA, except for these batteries being a closed system, they are slightly more expensive. However, no maintenance of the water level needs to be performed. Additionally, these batteries handle temperature fluctuation better than FLA.
Lithium-Ion: These batteries are the best on the market. They have longer lifespans, better efficiency, and no maintenance. The only downside, from my perspective, is the cost. For example, this lithium-ion 100ah battery from Renogy is priced at $722.49 (at the time of this writing).
Choosing the correct battery for your system depends entirely on how much money you budget for the project, how much time you want to spend on maintenance, and your system's overall use. For our system, we use a sealed lead-acid 100AH battery from Renogy. We currently have 12 in our battery bank.
Step 5: Inverter
This part is vital because there is a specific part that is crucial to how I've built my system, and if you are going to follow this method, you need to have a similar function. The terminal block is a part of the converter on the front of the machine. It has a positive, neutral, and ground. So what I did was run those wires from the inverter into the circuit breaker.
The circuit breaker size is dependent on your system. You want to ensure you don't get too small or too large of an inverter. My system is 2400W. I could have gone with a 2500W inverter, but that would have been cutting it a little close. So instead, I have a 3000W inverter for our system.
Step 6: Circuit Breaker Box
Circuit breakers are a safety mechanism designed to "trip" when they detect the passing current exceeds their amperage. If they did not shut themselves off when confronted with a surge of electricity higher than their rating, they could disable your entire system. This would be a costly mistake, not to mention inherently dangerous.
When choosing your breaker box, you need to calculate the total amperage of your ENTIRE SYSTEM. Every appliance and lightbulb you intend to use must be considered in this equation.
Usually, most of the outlets and light switches in your house will be