Tuesday, March 21, 2023

What Kind Of Solar System Do I Need

How Many Watts Do You Currently Use

How To Size Your Off Grid Battery Bank Capacity For Solar – Math Warning!

Look at your electricity bill for average usage. Look for Kilowatt Hours Used or something similar, and then note the length of time represented . If your bill doesnt show kilowatt hours used, look for beginning and ending meter readings and subtract the previous reading from the most recent one.

You want daily and hourly usage for our calculations, so if your bill doesnt show a daily average, just divide the monthly or annual average by 30 or 365 days, respectively, and then divide again by 24 to determine your hourly average electricity usage. Your answer will be in kW.

A small home in a temperate climate might use something like 200 kWh per month, and a larger home in the south where air conditioners account for the largest portion of home energy usage might use 2,000 kWh or more. The average U.S. home uses about 900 kWh per month. So thats 30 kWh per day or 1.25 kWh per hour.

Your average daily energy usage is your target daily average to calculate your solar needs. Thats the number of kilowatt-hours you need your solar system to produce if you want to cover most if not all of your electricity needs.

Its important to note that solar panels dont operate at maximum efficiency 24 hours a day. . Weather conditions, for example, can temporarily reduce your systems efficiency. Therefore, experts recommend adding a 25 percent cushion to your target daily average to ensure you can generate all the clean energy you need.

Solar Panel Output Per Square Metre

The most popular domestic solar panel system is 4 kW. This has 16 panels, with each one:

  • around 1.6 square metres in size
  • rated to produce roughly 265 watts of power

To work out the output per square metre, use this formula:

Number of panels x Capacity of solar panel system

Capacity ÷ Total size of system


  • 16 panels of 265 W each:
  • 16 x 265 = a capacity of 4,240 kW
  • Total size of the system
  • 4,240 ÷ 6 = 165 W per m2

Determine Your Budget For Solar

How much solar you need is determined more by your budget than any other factor. 190 Watt Solar panels each have a cost associated with their purchase and installation. If you have a large budget , you can most likely skip this step. If you have a smaller budget, then this may be the overall limiting factor of your RV Solar system.

Sample RV solar kit cost as of January 2020

  • 190 Watt Solar Panel Kit with 30 Amp PWM Charge Controller ranges from $600 to $700
  • 190 Watt Solar Panel Kit with MPPT-40 Amp ranges from $950 to $1050
  • Each additional 190 Watt solar panel expansion kit ranges from $440 to $540 dollars each

How much solar can I get on my RV for around $700?

Currently, the most efficient panels on the market are around 190 watts. These panels will give you the greatest bang for your buck while minimizing the number of panels needing to be mounted. A 190 watt solar kit with wires and charge controller from a quality brand will run you less than $700.00 if you use a PWM controller.

What is the best solar panel to use?

The best solar panel today is the 190-watt solar panel. It produces about 9.6 amps and very efficient. A high-quality 190-watt panel will produce about 9.2 amps on a 70-degree sunny day with an average altitude in the southern U.S.

Can I add more solar as funds become available?

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How To Fuse Your Solar System

Technical Representative

When hooking up your Renogy system,the best way to add protection is by using fuses or circuit breakers. Fuses andcircuit breakers are used to protect the wiring from getting too hot and alsoprotect all devices connected in the system from catching fire or gettingdamaged if a short circuit occurs. They are not necessary for the system to runproperly, but we always recommend using fuses or circuit breakers for safetypurposes. There are three different locations that we recommend installingfuses or breakers: first, between the charge controller and battery bank,second, between the charge controller and solar panels, and third would be betweenthe battery bank and inverter.

Todetermine the fuse size needed between the charge controller and battery bank yousimply match the amperage rating on the charge controller. For instance, if youhave one of our 40Amp charge controllers, we would recommend using an 40Ampfuse.

Thelast fuse that we recommend in the system would be if you are using aninverter. This fuse would be between your inverter and the battery bank. Thefuse size is usually stated in the manual and most inverters already have builtin fuses/breakers. The rule of thumb that we use here would be ContinuousWatts / Battery Voltage times 1.25, for example a typical 1000W 12V inverterdraws up around 83 continuous amps and we would add the 25% safety factor whichcomes out to 105 Amps, so we would recommend a 150A fuse.

Your Current Energy Consumption

Woodhugger Engineering web logs: You Do The Math

Many solar customers desire a system that generates equal to or close to the amount of energy theyre consuming each month. To get a feel for your current energy consumption, look at your watt usage over the last 12 months. Depending on your situation, you may need more or less solar panels to potentially reduce your bill.

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How Many Kwh Can Your Solar Panels Produce The Complexities Of Production Ratios

The amount of power your solar energy system can produce depends on how much sunlight exposure your roof receives, which in turn creates your production ratio. The amount of sunlight you get in a year depends on both where you are in the country, and what time of year it is. For instance, California has more sunny days annually than New England. But in either location, youll be able to produce enough power to cover your energy needs and say goodbye to your utility billsif you live in an area that gets less peak sunlight hours, youll just need to have a larger solar array system installed at your home. Thus, production ratios differ according to geographic location and a lower production ratio means youll need more solar panels to get the amount of energy production you need.

Choosing The Right Solar Panels

There are plenty of solar panels on the market to choose from, but only a handful of them will provide a long, efficient experience. If youre trying to decide between premium and cheap solar panels dont miss covering the topic.

We recommend installing solar panels that fall into the top two tiers of quality from manufacturers that have Australian support for customers.

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Focus On Quality Rather Than Quantity

Though all solar panels convert the suns energy to electricity that your home can use, theyre not all made to the same high standards. You get what you pay for and lower quality panels will typically cost you less up-front, but youll end up having to replace them more often.

More expensive panels are typically higher quality and will last for decades without getting damaged by the elements.

Its always best to invest in fewer high-quality panels than it is to buy more low-grade panels. Many panels come with a warranty which will cover the cost in the event the panels need to be replaced.

Check For Neighborhood Restrictions

How Much Solar Power Do I Need? How to Calculate Your Needs

If you live in an area without a homeowners association, youre likely able to install panels anywhere on your property without issue. However, if you live in a neighborhood with an active HOA, youll need to find out if there are any restrictions in place.

Unfortunately, HOAs can dictate whether you can install panels on your property. If theyre not and you choose to install them anyway, the HOA can fine you and ask that you remove the panels for good.

Unfortunately, HOAs can sometimes dictate the location of solar systems when it comes to the front yard or front portion of a roof. However, unless you live in a condo or the HOA technically owns the land and the roof itself, they cant completely bar an install. Many times a condo contractor can work with you to make sure their aesthetic restrictions are accommodated.

Save yourself the trouble and learn about any restrictions before scheduling a consultation with an installation expert. This will save you time and money down the road.

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How Do I Calculate A Solar Panels Output

Because every solar panel system is different, its hard to say exactly how much electricity yours would generate. This useful calculator by the Centre for Alternative Technology can give you a rough idea, as well as the amount of money you could expect to save.

There are also a few general benchmarks you can use to estimate your systems potential output.

What Are Your Savings Expectations

Do you want to offset your electricity costs, neutralise them or aim to earn a credit from your power company every quarter?

Your savings expectations directly impact the number of panels you should install on your home, as well as other factors such as location and installation conditions. Since solar panels thrive on sunlight, locations with more daylight hours will require less panels to achieve the same result than areas that receive less daylight hours, such as Hobart.

Other influential factors impacting on energy production include solar panel shading, orientation , changing seasons and weather conditions. Your solar power retailer may add a small buffer on top of your average daily production to offset these factors.

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How Many Solar Panels Do You Need For Common Household Items

If you are considering solar energy for your home, you may also be asking how many panels are needed to power specific appliances. However, it is important to understand how solar generation works:

  • Solar systems deliver most of their energy production in the hours around noon
  • During the early morning and late in the afternoon, solar generation is much lower. This is because there is less sunlight reaching the panels
  • Households have the highest energy consumption in the evening and early morning

Since solar panels depend on sunlight, you cannot control their electricity production. Powering home appliances directly with panels is impractical and potentially dangerous, unless you use a solar battery to store energy. If you connect home appliances directly to the panels and inverter, a dark cloud passing over your home will shut off the power. At night, you would have to switch to the local power supply anyway.

The most practical solution is synchronizing solar systems with the local power supply, which lets them operate as a single power source. When solar generation cannot power your home appliances by itself, the rest of the energy comes from the grid. If your panels have surplus production, you can send it to grid to get a credit on the next electricity bill.


This table considers the most power-hungry appliances found in homes. Most small appliances and electronic devices have a very low consumption, which does not even match the production of one panel.

More About Home Batteries

Solar System Builder Game

To figure out what type and how many batteries you need, you must first understand some details about home batteries themselves. There are 3 main factors that will influence the solar panel owners decision about a home battery:

CapacityThe capacity is the total amount of electricity that the battery can store. This is measured in kilowatt hours and represents how big the battery is. For example, Tesla Powerwall 2 has a 13.2 kWh capacity. Check this video to know more about kilowatt hours.

Power RatingThe power rating for a solar battery is the amount of electricity that can be delivered at once. This is measured in kilowatts and directly impacts that quantity of electricity that can be drawn from the battery. So, if you want a battery that can power many of your household appliances and devices at once, you will need a high power rating. Depth of Discharge The DoD is simply the amount of charge that was used by a battery. For example, if the battery has a 30% charge left, then the DoD is 70%. The reason why the DoD is important is that due to the chemical composition of some home batteries, you must ensure the DoD never gets to 100%. This means that for most home batteries, you will need the capacity to be slightly larger than the maximum amount actually needed.

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How Much Solar Power Do You Need

So you want to set your rig up for Solar but you are not sure what size of set up you need? This blog is designed to give you the tools needed to be able to work out exactly what are you are drawing from your rig’s batteries and what type of solar set up you need. Knowledge is key when setting up your rig for solar so the more information you have on each and every one of those home comforts devices you plan to take away with you the better. If anyone has a question pop it in the comment section below. I will try my best to answer everyone.

How to work out Watts, Amps and Volts

A larger solar panel will collect more energy in less time, but just how big does the solar panel need to be?

The power consumption of appliances is usually given in Watts. To calculate the energy you will use over time, just multiply the power consumption by the hours of use. For example:

10 watt device used over 3 hours equals 10 x 3 = 30 Watt

How to convert Amps to Watts

The energy in Watts is equal to the electric charge in Amps times the voltage in volts:

Watts = Amps × Volts


If your device doesnt have the Watts labelled on it, then it should at least have the input Volts i.e. 240V and the Amps AC it draws such as 240V 1.5A. You can then use the equation Watts Volts x Amps so 240v x 1.5amps = 360 Watts.

How to convert Watts to Amps

The electric charge in Amps is equal to the energy in Watts divided by the voltage in volts :

Amps = Watts / Volts


Do I need a battery?

Energy Usage And Load Profile

As we want to size the solar system to generate the most energy to cover your own energy needs, with minimal exported energy, it is necessary to know how the building uses energy. This is also called an energy usage load profile. But in absence of this data, we can assume a flat load profile. If a building has a flat load profile, then solar can only cover 30% of a building’s usage.

For example, if a building has a flat consumption of 20 kW and one installs a 24 kW solar system. Assume the system generates at 80% of its rated power due to losses and less than optimal solar radiation. Then the following load and generation profile will be created.

This will give the following total figures per day.

Total energy used per day 480 kWh

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Can I Store The Electricity My Panels Generate

Batteries for storing solar energy are now available in the UK. However, the technology is still fairly new and so these products can be quite expensivealthough, as with solar panels, the cost is gradually coming down.

When you register your solar panels with the Governments Feed-in Tariff , you receive payments for electricity you produce but dont use yourself. But because this payment is capped at 50%, its still in your interest to use as much of your electricity as possibleincluding storing it in a battery and using it as night.

Any battery you install must be compatible with your solar panels and have the correct voltage. Your solar panel installer will be able to tell you what kind of battery is best for you.

Types Of Solar Panels

Off Grid Solar Power – How to Calculate Your Needs

The three types of solar panels. Each of these types of solar cells is made in a unique way and has a different aesthetic appearance.

  • Mono crystalline
  • Each module is rated by its DC output power under standard test conditions and hence the on field output power might vary. Power typically ranges from 100 to 365 Watts . The efficiency of a module determines the area of a module given the same rated output an 8% efficient 230 W module will have twice the area of a 16% efficient 230 W module. Some commercially available solar modules exceed 24% efficiency. Currently, the best achieved sunlight conversion rate is around 21.5% in new commercial products typically lower than the efficiencies of their cells in isolation. The most efficient mass-produced solar modules have power density values of up to 175 W/m2 .

    Scientists from Spectrolab, a subsidiary of Boeing, have reported development of multi-junction solar cells with an efficiency of more than 40%, a new world record for solar photovoltaic cells. The Spectrolab scientists also predict that concentrator solar cells could achieve efficiencies of more than 45% or even 50% in the future, with theoretical efficiencies being about 58% in cells with more than three junctions.

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    Planning A Home Solar Electric System

  • Energy Saver
  • Planning a Home Solar Electric System
  • There are a number of steps to follow when planning to power your home with solar energy. After choosing which option is best for you to use solar , follow the steps afterward that apply to you. Your solar energy installer and local utility company can provide more information on the exact steps you will need to take to power your home with solar energy.

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