How Long Does It Take To Charge An Electric Car With Solar Panels
The calculation to work out how long it takes to charge an electric car with solar panels depends upon the electric car itself and the voltage of the solar panels. For this example, we have taken the average car battery size which is 54kWh and the average domestic solar installation is around 4kW. A panel was this size will generate 3,400 kWh a year = 9 kWh / day.
At this calculation, it would take six 4kw solar panels to charge an electric car battery to full capacity in a day.
However, the average driver travels 37 miles per day, so it is unlikely you would need to ever charge all day or for the full day to reach maximum battery potential. 37 miles per day translates to about 12 kWh of electricity. Most solar panel systems include around 25 to 30 solar panels, meaning the actual charge time of a day would be significantly less.
The 368kw Limit Per Phase Relates To The Acoutput Of The Inverter Not The Capacity Of The Solar Panel System
The DNO has a limit on the amount of output you can connect to the grid without needing permission. Output and PV capacity are not the same or directly comparable. Its important to understand the difference to ensure you get the most productive system possible and avoid missing out on £000s in lost generation. We explain below.
Ensure that your system designer or salesman understands the difference to avoid ending up with a significantly underperforming system.
First, let us explain what the capacity of a solar panel system means
In the real world, especially in the UK, irradiance fluctuates significantly. Here in Hove, we can expect irradiance to fluctuate from 0W/m2 to 1200W/m2 .
What does this mean in practice?
In the example shown , we have a south-facing, unshaded 16-panel, 6.2kW system with a good quality 3.68kW inverter.
According to the weather station at Birmingham airport, the maximum irradiance the array will receive is 1006W/m2. Irradiance fluctuates significantly throughout the day/year.
Therefore, during the summer we can assume, on a clear day from 12-1 pm the array will produce 6.23kWh. .
The inverter can deliver 3.68kWh to the AC side.
2.55kWh is AC clipped – lost as heat via the inverter and/or module.
The simulation software calculates the yearly losses to AC clipping for us:
190 kWh is lost per year to AC clipping – worth £6.65 – £32.30 depending on whether or not you can use the energy.
Total output of 6.2kW array = 5908 kWh
AC clipping: 0 kWh
What To Consider Before Choosing Solar Panels
If you are thinking about having solar panels installed, youll need to consider whether your roof is suitable, including whether it is big enough and how much sunlight it gets.
Youll also need to think about what size solar panel system you need. Its important to ensure the size is big enough to cover your homes energy needs, but also that you dont end up with a large surplus.
You may also want to think about installing a solar battery or energy storage system which will store the electricity your solar panels generate. This will allow you to store electricity generated in the day to use at night, helping you to become more self-sufficient and reduce the amount of electricity you use from the Grid.
Although you dont usually need planning permission for the installation of solar PV panels, it is also wise to check with your local authority in case there are any restrictions for example, if you live in a listed building or a conservation area.
You should also inform your home insurance provider to ensure they will cover solar panels and find out whether your premiums need to be adjusted.
Finally, make sure you get several different quotes from companies to compare installation costs. It may be best to look for a certified installer on the Microgeneration Certification website.
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Rated Output Specifications And Solar Panels
Rated output for solar panels at different light intensities . The knee of the curves is where the most power is produced, and the voltage & current is optimized.
Open Circuit Voltage
Open circuit voltage is how many volts the solar panel outputs with no load on it. If you just measure with a voltmeter across the plus and minus leads, you will read Voc. Since the solar panel isnt connected to anything, there is no load on it, and it is producing no current.
This is a very important number, as it is the maximum voltage that the solar panel can produce under standard test conditions, so this is the number to use when determining how many solar panels you can wire in series going into your inverter or charge controller.
Voc will potentially be briefly produced in the morning when the sun first comes up and the panels are at their coolest, but the connected electronics havent woken up out of sleep mode yet.
Remember, fuses and breakers protect wires against over-current, not over-voltage. So, if you put too much voltage into most electronics, you will damage them.
Short Circuit Current
Short Circuit Current is how many amps the solar panels are producing when not connected to a load but when the plus and minus of the panels wires are directly connected to each other. If you just measure with an ammeter across the plus and minus leads, you will read Isc. This is the highest current the solar panels will produce under standard test conditions.
Maximum Power Point
What Is Included In My 4kw Solar Installation Kit
Our kits provide all the solar components you need from start to finish.
- Solar Panels – 10x 400W Tier-1 144-cell monocrystalline panels with 25 year warranties.
- Micro Inverters – 10x Enphase Micro Inverters.
- Racking and Attachments – Industry leading IronRidge racking mounts the solar panels to your roof.
- System Monitoring – Free with every kit purchase! View and analyze your solar energy production in real-time.
- System Design and Financial Analysis – We’ll custom engineer this system for your roof and calculate the payback on your solar investment.
- Not Included – Wire, conduit, fittings, breakers, AC/DC Disconnects , junction boxes and a sub panel . All these items can be purchased at any electrical supply shop, Home Depot or Lowes, and will typically cost $300 to $500. Our technical support representative will provide a shopping list once your plans are complete.Plans, interconnection, and any other services are not included in this kit, but available for an additional fee.
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What Can You Power With A Single Solar Panel
In the example above, the solar panel is producing 1.5 kWh per day, which ends up being about 45 kWh per month. Thats enough energy to power some small appliances without too much issue, but if you want to cover the energy used by your propertys climate control systems or large cooking appliances, youll need more solar panels. Check out our article on how many solar panels you need for your home to better understand how much solar energy your unique property needs.
Sizing Up The Solar System
Once we understand the output curve of a solar system, we can then try to size up a solar system so that you use most of the solar power over the course of the day to maximise the benefit of the system.
Most households will use more power than the solar system generates early in the morning and later in the afternoon, and a lot less than what the solar system outputs during the middle of the day. We expect most households will be able to use up to around 70% of the solar power in the home as it is produced, although many households do a lot better than this.
Having installed thousands of smart solar systems with online monitoring, we now have a very clear picture of how households tend to use electricity:
- The baseload: fridges, freezers, lights, fish tanks and anything else left running most of the time
- Daily usage: pool pumps, air conditioning, appliances such as the dishwasher, washing machine etc.
- Peaks: the toaster, hairdryer, heat lamps in the bathroom, a big air conditioner turning on
Typically when sizing up a solar system, we try to cover all of the baseload, plus as much of your daily usage as is practical/affordable.
The big spikes in power usage wont be covered by the solar system as it just isnt worth it. As an example, doubling the size of your solar system to cover a 10-minute spike of power usage from the bathroom heat lamps doesnt make financial sense.
The other factor to all of this is managing when you use your power.
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Forget Single Solar Panelshow Much Energy Will Your Whole System Produce
Knowing how much energy a single solar panel produces is all well and good, but more importantly, how much solar power can your roof generate? Lets do the math below:
Take our example above, where youre getting an average of five hours of direct sunlight per day and using solar panels rated at 290 W. Lets say you install 30 of those premium solar panels on your roofthat nets you a 8,700 watt, or 8.7 kW solar panel system, near the average system size purchased on the EnergySage Marketplace. Multiply the five direct sunlight hours we estimated above by 8.7 kW, and we get approximately 43.5 kWh of electricity produced per day. And for one final conversion, if we multiply 43.5 by 365 days in a year, we get approximately 15,800 kWh of electricity produced in a full calendar year from a rooftop array of 30 premium, 290 W solar panels. Considering the average electricity use per year in the U.S. is around 10,600 kWh, thats probably more than enough to power your home on solar.
This estimate is likely on the high end for most solar shoppers, and likely because of our estimate for the amount of sunlight the system will get . To learn more about average sun hours, check out our blog here, where we take a look at average sunlight per year by location.
How Much Does A Solar Power System Produce
One of the biggest misconceptions people have when sizing up a solar system is to think that a solar power system produces its size, for example, a 5kW solar system will produce 5kW of power at any one time.
The reality is a 5kW system will output a bit less than that, with peak output on a good day being somewhere between 4kW and 4.7kW during the middle of the day, and a less in the morning and afternoon:
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What Determines The Amount Of Electricity Produced
There are actually four main factors that will determine how much electricity your solar panels will be able to produce for your home. These are as follows:
The size. This is the most important factor out of the four, as the larger the system is, the more electricity it will produce. If you are looking at a typical installation, it is a 3.5kw system, and this tends to be around 12 panels. Alternatively, the 1kw domestic system is likely to only be two panels.
Direction. This is the next most important factor. The direction in which your roof faces and its angles are more important than you might think. For optimum performance levels and efficiency, your panels should be facing south at an angle of 35 degrees.
The area of your roof that has the solar panels installed should not be in the shade during the day. Allowing the panels to be in the sunlight all day will increase the amount of electricity that you are able to produce.
Seasons. The time of year can also have an impact on efficiency and energy production. During the summertime, there are longer hours of daylight, so you will be able to produce a lot more power. However, it is also important to remember that solar panels actually work by capturing light as opposed to heat, so it will produce energy throughout the year.
How Much Power Output Does Your Home Need
This all depends on two things: how much electricity you use, and how much of your home you want your solar panels to power.
If your household has a particularly high energy usage, or you want to solely rely on solar panels to power your home, wed recommend getting solar panels with a high output around 300 watts or more.
However, if you dont use much electricity day-to-day, or only want solar panels to subsidise some of your homes energy usage, you can choose solar panels with a lower output around 225 to 275 watts.
Most homes will install several solar panels, known as a solar panel system. A typical 3-4 bedroom house will require a 3-4kWp solar panel system, typically composed of 12-16 solar panels.
The output of a solar panel system can be calculated by multiplying the wattage of each solar panel by the total number of solar panels. For example, a home in Reading with four 250-watt solar panels would have a 1 kilowatt solar system .
Most domestic properties have between a 1kW and 4kW solar panel system, depending on how much power they need and the size of their roof. The table below shows you how much electricity different sized solar systems normally generate over a year, as well as how many solar panels theyre typically made up of:
|Solar panel system size|
|28 sq. metres||3,400 kWh|
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How Much Energy Does A Solar Panel Produce
Generally speaking, a 3kw or 4kw solar panel array will be able to produce enough energy to power a home containing a family of four or five people. A 2kw or 3kw array, on the other hand, will be able to supply enough energy to power a smaller home. A 4kw system will, on average, generate around 3,400kwh of electricity per year. When we break that down, we can see that it is enough to provide:
- 4,857 hours of the washing machine
- 97,143 hours of the fridge
- 1,880 hours of boiling the kettle
- 1,417 hours of the oven
Of course, every solar panel array is different, and so it can be tricky to determine exactly how much energy yours will generate. So here are some of the basic facts for the average, domestically used, solar panel system.
- Domestic systems tend to range from 1 kilowatt to 5kW in size.
- A 1kw system can produce around 850kw per year, a 2kw system 1,700lw per year, and a 5kw system 4,500kw per year.
- The Energy Saving Trust estimates that a typical three-bedroom home in the UK will use just over 3,000kw per year. So, a 4kw or 5kw system would cover this.
- However, the Feed-in Tariff pays the highest rates for systems smaller than 4kW.
State Solar Panel Rebates & Deductions
Individual states and cities offer their own policies, incentives and credits, as well. Some utility companies will even offer 10 to 20% rebates on your installation. With these incentives, combined with the ITC, you may be able to save as much as 50%.
- Washington: Utility companies offer rebates up to $2,000
- Massachusetts: Utility companies which offer rebates of $0.50/watt and up to $625/kW.
- New York State: Tax credit of 25% for PV systems.
- Florida: Permanent sales tax exemption for solar energy products. Also several utility companies offering $500 rebates on solar water heating systems, which cost an average of just over $3,500.
Leave Solar Panel Installation to the Pros
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Im On A Green Tariff So Can I Use As Much Electricity As I Like
Its important to bear in mind that signing up to such a tariff does not mean you can leave all your lights on because its all zero carbon! If you use more electricity through your green tariff it means that less renewable electricity is left for those that are not on green tariffs. This means that more fossil fuel will be burned to meet their share of energy use.
Also, every means of generating electricity has some environmental impact, including the energy and materials that go into manufacture and installation. Energy saving measures are vital, because its them much easier to meet our electricity needs with energy sources such as wind farms, and wave & tidal power. Our Zero Carbon Britain project has a lot more details about how we can meet all our energy needs using only renewable energy.
It sounds great in principle to heat your house using a heat pump, and get the electricity needed using solar photovoltaic panels.
However, the UK climate makes this impractical. Very little solar energy is available at the time of the year when your heat demand is greatest. A fairly large 4kW solar PV roof will produce around 15kWh of electricity per day in May or June, but only 3 or 4 kWh on a typical day in December or January. A heat pump may need about twice as much electricity as this, plus youll have several other electricity demands to meet.
How Do I Improve The Output Of My Solar Panels
There are 4 key factors that will determine just how much electricity you can create with solar panels for your property:
- The size of the system is the most important factor of all. The typical domestic installation is a 3.5kW system, which is normally around 12 panels. A smaller 1kW domestic system is likely to be only 2 panels.
- The direction that your roof faces and the angle of the roof comes next. For optimum performance, your panels will need to be on a 35-degree angle, facing south.
- Having a roof that is not in the shade will increase the amount of electricity you are able to produce. Take a look at the handy table above, which shows you what output volume can be expected from a domestic solar installation.
- The time of year will also have an impact. During longer daylight hours in the summer you will be able to produce proportionally more power. That said, its important to remember solar panels work from light not heat so will still produce energy all year round.
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