Off-grid Solar System for your RV, Boat, Cabin, Home, etc. – All you need to know!

You need to consider several things before buying your first Solar Panel for your home, RV, or other off-grid application. An off-grid solar system usually consists of 4 major components.

  • Solar Panel – Solar Panels convert solar energy to electric current (DC).
  • Solar Charge Controller – To monitor and regulate the electric current (DC) between your solar panels and batteries.
  • Inverter – Converts electric current (DC) from the batteries to alternating current (AC) that can power your devices.
  • Deep Cycle Battery – Stores the direct current (DC) from the solar panels.

My first Solar Energy System

My first Solar panel was a 40Watt solar panel with a 7A solar charger included, and I’ll explain these later in this article.

I bought my 40 Watt solar panel because my family and I moved from Canada to Kuje, a small city in Nigeria where we lived for 3 or more years. The solar panels were on sale for 50% off, and I was sure the solar panels would be needed.

To make a long story short, power outages in Kuje were common. There consistent days where power was intermittent at best and we did not have a regular source of power.

That solar panel ended up being useful, but quite inadequate for the needs we had and still have. I have since upgraded to a 200Watt panel and I hope to expand even more in the future. Below are a few things I should have considered before buying my first solar panel system. (2020 Update – I have expanded to a 700-watt system).

What do you need Solar Power For?

Solar Panels today are more commonly installed to convert solar energy into electricity. This energy is then fed back into the power grid for distribution to get a rebate.

In off-grid situations, electricity generated from solar panels is used to charge batteries or power devices that use direct current (DC). If you are considering using your Solar Panels to feed power back into the grid, you may be better off consulting companies that specialize in these installations. They are not only experts at installing and optimizing your panel, but they will also inform you about all the government programs available in various states or provinces of your country.

Our focus for this site will be for those who are thinking of using Solar Energy for off-grid applications such as charging the batteries of your RV, boat, solar generator, water pumping machine, etc.  The most common solar panels for the home are 100 Watt Solar Panels.

What is the Power Rating of your device or the Rating of your Battery?

Before my first solar panel, I had never given much thought to the ratings of batteries. Now, the rating is the first thing I consider when looking to purchase a battery.

Batteries are rated by the amount of current they can deliver over one hour and the number of hours over which they can deliver one ampere of current.

Example: Theoretically, A 50AH battery can deliver one Ampere of current for 50 hours or 50Amperes of current for 1 hour.  This is pretty straightforward, but the problem with this rating is that most devices are rated in watts, including solar panels.

How then do you know how many watts of power a battery can deliver? You multiply the AH by the voltage to give you WattHour.

A 12 volt, 50AH battery can deliver 50 x 12 = 600WH.

This means that this battery can power a 600watt load for one hour, or a 60-watt device for 10 hours. This is the theoretical capacity of the battery.

In practice, however, this is not always the case due to variations in connection, temperature, and other variables. It is safer to use 80% of this capacity for planning. This means that our 12 volt 50AH battery can deliver 600 x 0.8 = 480 Watts of power for one hour.

Where do you find the Rating of your Battery?

The Rating of your battery can be found on the battery itself. Even small alkaline AA or AAA batteries have this rating. I had always wondered why the same set of AA batteries from different manufacturers had different costs. Then I discovered that the higher the AH, the more valuable the battery, and the higher the cost.

How Much Sunlight Do You Receive?

The amount of sunlight you receive will determine how long it takes your solar panels to charge your batteries. The amount of sunlight can vary by season, time of day, and where you are located geographically.

The map below illustrates the average number of hours received in different geographical regions of the western hemisphere. Most regions average 3-5 peak sun hours. This varies by season with many areas receiving more or less sun.

Map of Solar Irradiance

Do You Have Room to Place Your Solar Panels?

The amount of room you have for your solar panels will determine how efficient they are, and what type of panels you want to purchase. Solar panels are rated for direct sunlight. If you do not have access to direct sunlight, they will not function as efficiently as they should or are rated.

A 100 Watt panel may function at 50Watt level if it is only receiving 50% of the expected sunlight.

Cost is Definitely a Factor

If you don’t have much room for solar panels then you may end up spending more money on high-end monocrystalline panels to gain efficiency and output.

If you are going to need energy at night, you will need a good battery back-up system. Solar Panel systems are typically expandable, but make sure you plan out your system well, so your budget does not get away from you.

I ended up expanding my solar panel system three times, and even installed one in another building.

Solar Power Components

Solar panels do not usually stand-alone. To set up an off-grid solar power system you will need the following basic components. I will provide a non-technical explanation for each device below.

Deep Cycle Batteries

Many people use solar systems more at night than they do during the day since they are home. An off-grid system (that is, a system that is not connected to any other source of electricity from the city) will need a way to power your appliances at night when there is no sunlight.

You will need enough batteries to power your appliances and lighting points through the night. The more devices you have, the more battery power you need.

Power Inverter

A power inverter is used to convert direct current (DC), supplied by batteries, to alternating current (AC) used by most home appliances and devices. Without a power inverter, you cannot power your devices with only a bank of batteries.

There are two primary types of power inverters for personal use. The Pure Sine Wave Inverter and the Modified Sine Wave Inverter. The Pure Sine Wave Inverters produce electricity that is similar to power supplied by the electric company. Pure Sine Wave Inverters are more expensive than Modified Sine Wave Inverters.

The Modified Sine Wave Inverters produce a current which may not be appropriate for sensitive equipment. Most people purchase the Modified Sine Wave Inverters for lighting, powering basic power tools, and some basic home appliances.

Inverters come in different capacities and can range from 100 to 10,000 watts. This is a critical component in any DIY Solar System so make sure it is sized correctly for your system requirements. You can check out my posts on the different sizes below.

Solar Charge Controller

Charge Controllers regulate the current supplied by your solar panels to charge your batteries. The solar charge controller helps prevent your batteries from being overcharged and destroyed.

Battery Rack and Extra cables

Depending on the distance between your panels and your batteries, you may need extra cables. You may also need cables to connect your charge controller to your inverter.

You may also need extra cables to connect your batteries in a series or parallel. Cables appear to be a theme. As you layout your system during the planning phase, make sure you have enough cables for all of the components.

Conclusion

This article provides a high level overview of components you will need for your first solar power system. Building a good system can be very satisfying and provide peace of mind where power is needed.

If someone were to ask me what I think is most important, I would tell them planning and learning. Make sure you layout your system and determine what you will need before making purchases. Plan for the future growth of the system and educate, educate, educate.

There are TONS of resources available now. You can even find solar companies offering free classes, so take advantage of these.

DIY Solar Resources

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