Saturday, February 17, 2024

What Size Off Grid Solar System Do I Need

Avoid Solar Panel Shading At All Costs

Off Grid Solar – What size system do I need?

Secondarily, solar panel suffer greatly when they are even partially shaded by trees, building, and any obstructions that might be present. You might think that having your panels only 10% shaded we just reduce the power output by 10%. Yet in most cases it will reduce the total power output by at least 1/3. And depending on how your panels are wired, it could reduce the total array output by 1/3, not just the one panel. So, unless your home is completely free from shading, especially in the winter, it is frequently cheaper overall to put your panels a little distance away from the house where they will receive full sun all your long.

Where Do I Get A Quote

You can start looking for quotes from solar contractors by reaching out to your local library or utility company, who may have lists of companies you can contact. You might be surprised at how many different types of people are in the industry! Theres also an app that lets you compare prices from multiple installations in your area.

How To Size An Off Grid Solar Pv System For The Home

What is currently happening in our world

With the planet continuing to warm up and the increased pressure on humanity to ditch fossil fuels and embrace other forms of energy that dont harm the planet, renewable energy has seen a steady rise in its popularity and usage.

Amongst the renewable energy sources of wind, solar and geothermal, Solar is increasingly becoming dominant. The main component of any solar energy installation are Solar PV panels. Although still relatively inefficient, the rise of Solar PV panels has been astronomical.

Solar PV installation in the rooftop of houses are increasingly becoming popular as we race to reduce our carbon footprint and keep the planet safer.

Basic Things to know Before you Start Your Solar PV Sizing Project in the Home

To successfully implement an off grid solar PV installation in the roof top of your house, there are some basic things you need to be aware of before you embark on this journey:

1.What is your load requirement?

2.Do you want to power all your loads when off grid ? Or

3.Do you want to power some loads and leave some on grid?

4.What is your budget for this project?

5.Can your budget finance a project where all your loads requirements can be taken off grid and powered by the Solar PV installation?

6.What is the average level of sunlight insolation in your location where the project is being planned?

Basic components of a Solar PV Installation in the Home

1.Solar PV panels

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Monocrystalline Thin Film Or Polycrystalline Solar Panels

Between monocrystalline and polycrystalline there isnt a lot of difference except that a polycrystalline panel is slightly larger. Regardless of size, a panel will output to its rating. However, the choice between monocrystalline/polycrystalline and thin film is a little more complex, explained in further detail here. Energy Matters generally recommends monocrystalline or polycrystalline for off grid and remote power applications. Pick up more tips on choosing solar panels.

Take The Stress Out Of Off Grid

How many solar panels do I need to power my home ...

Make the most of Commodores latest innovation, our updated Off Grid Calculator. This webpage has been designed to make life easier for you. We understand how difficult it is to choose the right solar system and also how difficult it is to calculate Off Grid. So, we thought why not turn the complicated equations, and worrying decisions associated with going Off Grid into a positive experience, where you simply tick the boxes applicable to you!As the video above displays, all you have to do is:Select which products you use around the houseHow long you will use them for per dayBy you doing this, our off grid calculator can quickly calculate the:Potential Load KWAverage KWh Per DayWhich systems will be suitable to your power usageThe Winter average daily effective solar section is set at 3 hours per day. This is a conservative estimate based off the average number of effective solar PV input hours in Winter. Our research confirms that the national average annually is between 4 to 5 hours per day. This means 1kW of solar panels will produce between 4kWh to 5kWh per average day. In Winter our research indicates 3 hours of effective solar PV input to be the national average, and 6 hours of effective solar PV input to be the Summer average for Australia. Follow this link below to find the average for your area on a map.PV Performance Map AustraliaWith our tool, you can adjust the amount of effective solar hours to suit your location.

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Wiring Up For Off Grid Solar

With the panels up, now comes time for wiring of the system. This step doesnt need to be complex. Going off grid, with a boondocking RV, country cabin, or permaculture homestead, means that your electrical system can be much simpler than gird tie systems.

Going off grid means you have the option to install an all DC system, which can be quite simple and efficient. But even whole home replacement AC systems are possible for the DIYer.

However, if you intend to use your solar system and connect it to a home that is already connected to grid power, you are likely to be legally required to hire a licensed electrician to wire in your system, and you will need additional hardware from your utilities company to make your own energy system work with line power.

We talk about wiring your system in part 3 of this series.

Determining How Much Energy Solar Panels Produce

As you might have guessed, the amount of power that your solar panel produces depends on how much sun they gets. That means during the shorter days of winter you will get less power. Also, cloudy days will give you much less power than sunny days.

Again, the best way to know how much power your solar panels will produce is to measure it. Buy one solar panel and measure how much energy you can produce throughout the year. Not every year is the same, so you will need to oversize your system just a little bit in order to account for usually dark or cloudy years.

However, you may just want to get a rough estimate of how much solar power your panels were produce. Luckily the US government has produced solar power availability data for the entire United States.

The map above shows on average how much power your solar panels will produce per day. The number depends on the color of your area it ranges from about two to eight. This number can be multiplied by the power rating of your solar panels to determine how much power they would produce. So if you live in an area labeled as three on the map and you bought a 1 kW Solar panel array then you would get 3 kWh of energy produced per day on average.

This assumes that you have full access to the sun so long as it is up. If location of your solar panels is partially shaded, especially during mid day, then you will get less power than the map shows.

Recommended Reading: How Much Solar To Run Rv Ac

Questions Related To What Is Off Grid Solar System:

How many solar panels do I need for 5000 watts?

There are two ways of looking at this. You would need 17 solar panels rated at 300 watts, 25 solar panels rated at 200 watts and 50 panels rated at 100 watts to build a 5000 watt solar power system.

However, this would only give you the solar system rated power, not the actual output in watts.

Due to PV system losses of about 23%, the number of solar panels required should be multipled by 1.44 when sizing solar panels. In this case you would need 24 solar panels rated at 300 watts.

What can a 5000 watt solar system run?

A 5000 watt solar system with an average irradiance of 4 peak-sun-hours will generate 20kWh per day.

The average energy consumption for an American home is about 30kWh/day, so a 5000 watt solar system wouldnt be enough to run all the appliances.

That said, such a system could run a lot, including washing machines, microwave, smaller kitchen appliances and TVs. Just dont include AC or heating.

How many solar panels do I need for a 2kW system?

Using 200 watt solar panels you would need just 10 to get the overall 2kW system rating.

A 2kW solar system would generate 8kWh per day when irradiated at the average 4 peak-sun-hours per day.

What can a 2kW solar system run?

A 2kW solar system can run a fridge, a freezer, general small kitchen appliances and a TV.

A 2Kw solar system isnt big enough to power any kind of heating or AC unit.

Can solar panels run 24 7?

How many solar panels do I need for 2500W?

What About A Battery

How to Size My Off-Grid Solar System & How Much Does it Cost?

A storage battery will capture the unused solar power generated during the day, for use at night and on low-sunlight days. Installations that include batteries are increasingly popular. See our case study of the first Australian home to install a Tesla PowerWall battery.

But for most homes, we think a battery doesn’t make economic sense yet. Batteries are still relatively expensive and the payback time will often be longer than the warranty period of the battery. However, it’s likely that battery technology and prices, together with future changes in how the electricity market works, will make batteries a good option for most homes within the next few years.

And remember: for most grid-connected systems, having a battery doesn’t necessarily protect you in the event of a blackout. You may still lose all power to your home, despite having solar panels producing power and a charged battery ready and waiting. This is because grid-connected systems have what’s known as “anti-islanding protection”. During a blackout, the grid and any engineers working on the lines must be protected from “islands” of electricity generation pumping power unexpectedly into the lines.

For most solar PV systems, the simplest way to provide anti-islanding protection is to shut down entirely. So, when it senses a grid blackout, your solar PV system shuts down and you have no household power at all.

Also Check: What Is The California Solar Initiative

How Much Does An Off

The prices of off-grid systems range from about $50 to tens of thousands of dollars. Thats because off-grid solar has such a huge variety of applications.

If we talk specifically about off-grid solar kits that can power an entire home, then prices range from $12,000 to $50,000.

You can get an idea of pricing from the table below it shows popular off-grid kits for different end-use requirements:


Can I Go Off

When it comes to creating and supplying your own electricity, there is possibly no greener technology more accessible and efficient than solar panels.

For the most part, going off-grid with solar panels is 100% possible. However, it is just one piece to the puzzle.

In order to maintain a healthy prolonged off the grid lifestyle, you will need some place to store all that solar energy generated by your solar panels.

And just like solar panels are the most accessible and efficient for electricity production, solar batteries/solar power stations, are the absolute best technology out there to store your off-grid solar energy.

So in essence, you can go off-grid with solar panels and some sort of storage system.

Read Also: Does It Make Sense To Go Solar

Choosing The Right Size Off Grid Solar System

You will need to size your solar system so that it can produce enough power to cover your winter and summer needs, which often means most of the year you will be producing more power than you can use.

Additionally, we need to account for the fact that solar systems are not 100% efficient. The process of transferring power from the panels to the charge controller, the charge controller converting it and storing in the batteries, and then the power coming out of the batteries and being potentially transformed into AC, all have some power loss associated with them.

While it is possible to go through each of your components and determine how efficient they are and thus calculate the perfect number of solar panels for your particular system, I generally just go with a 70% efficiency figure for typical after power systems.

To calculate how many kW of solar panels you need, including any inefficiencies in the system, just divide your energy needs by 0.7, or whatever figure you come up with for total system efficiency.

Look Up Your Peak Sun Hours


Average peak sun hours vary greatly depending on your location and local climate. Youll want to determine how may peak hours of sunlight youll get so you can make the most of the solar power:

  • Look up your peak sun hours, through a sun hours chart to determine the number of hours per day the sun produces peak sunlight.
  • Find the nearest city to you and write down the daily average of peak sun hours.
  • Recommended Reading: How Much To Go Solar

    Choosing The Right Place For Your Panels Is Essential

    Next, we take care to find and plan for the right site. Often, the top of the house is not the most efficient place for an off grid solar array. Choosing the right spot to prevent excessive shading and to ensure proper access and passive cooling for your solar panel can more than double the efficiency of your solar panels over their lifetime.

    What Does It Mean To Go Off

    Off-grid living is a characteristic of housing and lifestyle.

    The term off the grid can be associated with people that decide to disconnect their homes from the national electrical grid.

    Today, going off grid is still considered the ultimate path to living rough, but it does not have to be all that serious though.

    Off-grid living can also mean people create and utilize their own utilities, like gas, water and electricity generated from solar systems .

    In general, self-sustainable off grid homes tend to be popular in locations that are more isolated from common governmental utilities like electricity.

    However, isolated homes are not the only ones that make use of solar panels to generate their own electricity.

    Off-grid living also attracts environmentally conscious, forward thinking individuals who want to reduce their ecological footprint while saving on monthly utility costs.

    • In summary, taking your home off-grid means you are able to create/supply energy, drinkable water, grow food and manage waste/wastewater for yourself.

    Also Check: How Much Power Does A 350 Watt Solar Panel Produce

    Should You Buy A Solar Battery

    If you want your solar PV system to pretty much cover all of your energy needs, youll also require a solar battery.

    If you dont use solar-generated electricity immediately after it is created, then it will go back into the grid. Homeowners with solar panels need to be in their house during the daytime in order to use their solar energy, or else it will go to waste.

    However, with a solar battery, you can store up all the solar energy that doesnt get used. Then, once youre back home in the evenings and the sun has gone down, you can still power all your appliances with solar energy. Whats more, electricity from the grid is even more expensive in the evenings when demand is higher, so youre dodging the priciest time for grid power.

    You can find out more in our complete guide to solar batteries, which includes information about typical costs, pros and cons, and the best models on the market. Naturally, its the biggest batteries that are most capable of taking you entirely off-grid, such as the Tesla Powerwall 2.0 or the Sonnen Batterie eco .

    Figure Out How Many Solar Panels You Need

    How to Size your Solar Power System

    Now that weve determined battery capacity, we can size the charging system. Normally we use solar panels, but a combination of wind and solar might make sense for areas with good wind resource, or for systems requiring more autonomy. The charging system needs to produce enough to fully replace the energy drawn out of the battery while accounting for all efficiency losses.

    In our example, based on 2.5 peak sun hours and 240 Wh per day energy requirement:

    240 Wh / 2.5 hours = 96 Watts PV array size

    However, we need to account for real-world losses caused by inefficiencies, module soiling, aging, and voltage drop, which are generally estimated to be around 15%:

    96 array watts / .85 = 112.94 W minimum size for the PV array

    Note that this is the minimum size for the PV array. A larger array will make the system more reliable, especially if no other backup source of energy, such as a generator, is available.

    These calculations also assume that the solar array will receive unobstructed direct sunlight from 8 AM to 4 PM during all seasons. If all or part of the solar array is shaded during the day, an adjustment to the PV array size needs to be made.

    The maximum charge current for lead acid batteries is typically around 20 amps per 100 Ah and somewhere between this range is ideal .

    Here are standard configurations of PV arrays with battery banks. The battery capacity calculated in the previous step can be compared against this table to find a suitably sized system:

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    Understanding Your Electricity Usage

    You can’t correctly size your solar PV system unless you know how much electricity your home uses now . The easiest way to figure this out is to look at past electricity bills, which should tell you how much power you’ve used in the previous month or quarter. From this you can figure out the average daily usage. This is even easier if you have a smart meter installed you should be able to see your daily usage either on the bill or by checking your account online.

    Your power consumption is measured and billed in kilowatt-hours .

    A typical Australian home uses 1520kWh per day. But households can vary considerably in their electricity consumption, depending on the number of people living there, the area they live in, whether they use gas for cooking or hot water, and many other factors. For example, a single-person home will typically use about 812kWh per day on average, while a household of five people with a pool could use 3040kWh per day.

    Time of day and seasonal usage

    It’s important to consider when you use electricity. Is your home generally empty during weekdays, with everyone at work or school, so that your main power consumption comes in the evening? If so, your solar panels might not be used most effectively, as it’s better to use the generated power during the day than export it to the grid.

    Also consider whether some days are more power-hungry that others the weekend for instance, when everyone is at home. And do you use more power in summer or in winter ?

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