All About Solar Panels : Solar Panels Questions : Solar Panels FAQ

Solar energy and how to use it

How do solar panels work? Photovoltaics

What is solar energy in simple words?

Solar energy is the conversion of the sun’s energy into DC electricity that can be converted into the AC power used for domestic appliances. Solar energy is converted into electrical power by solar cells, also known as photovoltaic cells (PV).

What are 5 advantages of solar energy?

1. Solar energy is clean
2. Solar energy requires very little maintenance
3. Solar energy is environmentally friendly
4. Solar energy does not use fossil fuels
5. Solae energy is totally renewable

What is solar energy and its uses?

Solar energy is the use of solar PV cells to convert the sun’s energy into electricity. The energy is used commercially and domestically in homes. Domestic home solar systems convert DC power into the AC power need by the home’s appliances.

Video – All About Solar Panels – How Do Solar Panels Work? TED

What is the importance of solar energy?

Many people think that the most important aspect of solar energy is that it doesn’t use fossil fuels. This is massively important for the future of the planet, as resources of all kinds are fast running out.

Solar panels benefits

What are 3 advantages of solar power?

The 3 biggest advantages are:

1. Solar power does not use fossil fuels
2. Solar power is renewable
3. Solar power systems are guaranteed for 25 years

What are the 3 benefits of solar energy?

3 additional benefits of solar energy are:

1. Solar energy systems don’t need a lot of maintenance
2. Solar energy provides free electricity (after the payback period)
3. Solar power systems are fast to install and cheaper every year.

Types of solar panel

As far as solar cell types go, there are three main types:

1. monocrystalline
2. polycrystalline
3. thin film

Mono is the most efficient and thin film is the least efficient. Both mono and poly modules can be purchases in rigid or semi- flexible. Thin film is very flexible, but power output is poor.

Why solar energy is bad?

Solar energy is bad for the environment because of it’s potential for creating toxic waste. Solar panel recycling is not yet perfected and landfill disposal costs 3 times less than the best recycling process.

What are the 2 main disadvantages to solar energy?

The 2 main disadvantages of solar energy:

1. The cost of solar energy
2. Solar energy toxic waste products

What are the side effects of solar energy?

There are no side-effects of solar energy. There is no toxic by-products given off except when solar panels are at the end of their life and scrapped.

Recycling is preferred to landfill, but 100% solar panels recycling is expensive. There is no radiation given off by the solar energy process.

Is it bad to live near a solar farm?

It is not bad to live near a solar farm – 1 acre of solar panels or more make no noise or obvious pollution. There are no toxic by-products given off by the energy conversion process.

SOLAR PANELS FAQ

Solar panels information and facts

How long do solar panels last?

As a general rule solar panel manufacturer’s give warranties of between 25 to 30 years. The panels are guaranteed to produce up to 90% of their output when new after the warranty period.

Solar panels can go on generating power for up to 50 years, when the output levels off and stabilises at about 70% of the output when new.

Solar panels lose about 0.8% of their output power each year of use.

What is the biggest problem with solar energy?

Discover your solar saving potential

Enter your zip code

Calculate Now

Enter your full name

   Next

Enter your home address

Next

Most recent electricity bill, $

Additional Notes

Next

Phone number

Email

Submit

By clicking on "Submit" button you are agreeing to SolarEmpower's Terms of Use

Find out how much money you can save by going solar

100% free of charge

The biggest problem with solar energy is the potential for toxic waste leeching into the environment if the panels are not disposed of properly at the end of their life.

Do solar panels works at night?

No, solar panels cannot work at night. Output depends on a high level of irradiance, or sun’s energy, and they generate nothing in darkness.

The moon’s energy level is millions of times less than the sun.

Is solar power actually green?

Solar power is green in the sense that fossil fuels are not used to generate electrical power, so the Earth’s resources are not being depleted.

However, if old solar panels are disposed of in landfills, then heavy metals and other toxic elements can leech into the ground. This is definitely not green

How many solar panels are needed to run a house?

To run a house with energy consumption of 33kWh/day, 35 solar panels each rated at 300 watts would be needed if the average irradiance was 4.5 peak-sun-hours. The total calculated solar power rating needed will be 7333W. With solar PV system losses of 25% the actual total solar power required is 10566 watts.

Is solar power worth it in Ireland?

As a general rule solar power isn’t worth it in Ireland.

Solar panel output depends on the irradiation (peak-sun-hours) for any given location. The level of the sun’s energy in Ireland is very low at 1.868 peak sun-hours.

By comparison, some regions of the USA are approaching 6 to 7 peak-sun-hours.

Can a house run on solar power alone?

Yes, a house can easily run on solar power alone. This kind of solar power system is called an off-grid system and a substantial bank of batteries are required to power the home through the night.

Normally, the energy storage system for an off’grid solar power installation is sized to give autonomy for 2 to 3 days, just in case there is cloudy weather and solar output is low.

The cost of a suitably sized battery bank can equal 30% of the overall solar system cost.

How much does a 10kW battery cost?

A 48 volts 10 kWh battery is equivalent to:

Battery amp-hours (Ah) = kWh/voltage = 10000/48 = 208Ah

The Tesla 10kWh battery costs in the region of $3500.

SOLAR PANELS INFORMATION AND FACTS

Do solar panels melt snow?

Yes, even in winter solar panels get warm enough to melt snow, which slides of the surface which are normally mounted at an angle.

Solar panels get warm in operation, partly due to the solar cell conversion process and partly because the panel absorbs the sun’s heat.

Solar cells convert the sunlight into energy and not the sun’s heat. In fact, excess heat is the enemy of solar PV conversion.

Do solar panels work in rain?

Solar panels work in the rain and in any weather conditions that allow some sunlight to reach the surface of the panels.

The problem is that rains come from clouds, which shade the panels and dramatically reduce the output. In cloudy, rainy weather a solar panel array may only generate 10% of it’s potential power output.

Do solar panels work better in the cold?

As a general rule solar panels work better in the cold as long as the value of irradiance (sun’s energy) is the same.

Heat is the enemy of solar cell energy conversion, so reduced temperatures on a bright sunny winter day can generate very good power output. However, the sun’s angle is different in the winter so it may not result in more output.

Do solar panels work if covered in snow?

Solar panels do not work if completely covered, either with snow, dirt or anything else that blocks sunlight.

A light covering of snow on flat panels may allow some sunshine to pass through. Patchy snow on angles solar panels will tend to slide off as the panel warms up under the sun.

At what temperature do solar panels stop working?

Solar panels will put out less power as they get hotter, but don’t stop working.

The optimum temperature for solar cell energy conversion is 25 degrees C (77 F). For every degree over that level solar output reduces.

What are the negatives of solar energy?

The big negative of solar energy is the potential for spreading toxin waste if solar panels are not disposed of properly.

Solar panel end-of-life management should include a 100% recycling program to ensure that toxic chemical and heavy metals don’t leech into the ground from landfills.

Why is my electric bill so high with solar panels?

Your electricity bills may be too high because:

1. The solar panel system was not sized properly and may not be big enough for your needs.
2. You may have increased you home’s energy consumption by adding appliances.
3. The system Net Metering equipment should be checked to make sure credits are measured.

Are solar panels a ripoff?

A ripoff is a scam or a scheme run by unscrupulous people to take your money. It implies the sale of a product that is low quality, either in manufacture or it may not do what it’s supposed to do.

Solar panels are not a ripoff as hundreds of thousands of people have reduced or eliminated their electricity bills with home solar power system installations.

Poor solar panels can be a ripoff and it’s important to buy the best possible quality solar panels.

Are solar panels worth it 2021?

Solar panels are still worth it in 2021 – the Federal Solar Tax Credit program is still in force at 26%.

Is now a good time to buy solar panels?

There’s never been a better time to buy solar panels, for these reasons:

1. The price per installed watt is now under $3kW in many US states.
2. Solar prices are reducing every year (by a factor of 10 in the last decade!)
3. Solar panels are becoming more efficient
4. Electricity generated from fossil fuels will become more expensive with time
5. We must stop using fossil fuels – the planet is running out of them!

Do you still pay electricity bills with solar panels?

It depends on the size of your solar installation. The average US home energy consumption is around 1000kWh/month or 33kWh/day.

If your solar system is big enough to cover those needs then you will not pay any electricity bills.

Do solar panels work during power outages?

No, solar panels do not work when there is a power outage, because there is a danger to any emergency repair personnel working on the grid.

Automatic switching detects a power outage and disconnects the solar array. It’s called ‘anti-islanding’ and is a safety feature of grid-tied solar power systems.

The only way to maintain power is to install home energy storage batteries, such as te Tesla Powerwall. These batteries are kept topped up on stand-bye in normal conditions and then change to feed the home when the power goes out.

How much does it cost to put solar panels on your roof?

How long does it take for solar panels to pay for themselves?

As a general rule, solar panels are worth it in your state due to a combination of the Federal Tax Rebate, Net Metering buy-back rates set by the utility companies, and State incentives, such as sales tax and home improvement tax exemptions. The average solar power payback time in the USA is just 8 years.

Do solar panels need a lot of maintenance?

No, solar panels do not need a lot of maintenance. A good surface cleaning is recommended twice a year and checks on the electrical connections once a year is all that is needed.

What is the lifespan of a solar panel?

Solar panel manufacturers give warranties of between 35 years and 30 years, specifying a minimum power output at that end-of-life.

However, solar panels will continue to generate power for up to 50 years, gradually reducing their output at the rate of 0.7 to 0.8% each year.

Do solar panels require cleaning?

It’s recommended to clean the surface of solar panels twice a year. The accumulation of dust and dirt can significantly reduce the power output of a solar array.

Do solar panels need servicing?

It is recommended that connections are checked once a year and also to make sure there is no damage from hail or other falling debris.

They should be cleaned once a year, but apart from that, no servicing is required.

How often should I get my solar panels cleaned?

Solar panels should be cleaned twice a year to remove dust and dirt.

What is the best thing to clean solar panels with?

Soapy water is simply good enough for cleaning solar panel surfaces. Basically, it’s glass so you can clean them in the same way that you would clean windows.

The only thing to be careful of is that moisture or corrosive cleaning fluid don’t leak into any junctions boxes or micro-inverters.

Can you walk on solar panels?

Yes, you can walk on solar panels. They will stand your weight, but it’s not a good idea.

If not properly supported on aluminium rails the panels may flex and crack the bus-bars that connect the solar cells together.

Also, heavy boots and shows will scratch the glass, reducing the amount of sunlight reaching the solar cells and reducing output.

Can you clean solar panels with Windex?

Solar panels are covered in toughened glass so you can clean them with Windex or any product normally used for glass windows.

Can you use a pressure washer to clean solar panels?

Pressure washers can be used to clean solar panels. the covers are made form toughened glass and the solar cells are sealed between layers of flexible plastic.

The only thing to watch is that you don’t force water under pressure into connectors or junction boxes.

Can you use vinegar to clean solar panels?

Many people use a vinegar/water solution to clean glass windows and it can be used on solar panels as well. The surface of fixed rigid solar panels is toughened glass.

SOLAR INVERTER FAQ

FAQ about solar inverters

Which is best solar inverter?

There are many good quality brands of inverter but it’s important to buy a pure sine wave inverter. The output AC power wave form is much smoother and doesn’t cause interference problems with consumer electronics or appliance motors.

How much does a solar inverter cost?

Inverter cost depends on the quality. A good quality pure sine wave inverter costs about $0.27 per rated watt.

Can we run AC on solar power?

Solar panels output DC (direct current) and home appliances can’t use this – they need AC (alternating current). Home solar power systems need one or more solar inverters to convert DC to AC.

Can I use normal battery in solar inverter?

Any battery can be used with a solar inverter as long as the input voltages are respected. Deep cycle batteries should be used, as auto batteries should not be discharge more than 20% or they become damaged.

Lead acid deep cycle batteries can be discharged to 80% and lithium iron phosphate even more, to 95% without damage.

Can I use solar panel and inverter without battery?

An inverter can be connected to a solar panel without a battery but it is likely to cause problems.

If a cloud passes over the panel or it becomes shaded, then the power output may not be sufficient to run an appliance. Batteries act as a kind of power reservoir, supplying the load when solar output is low or non-existent.

Renogy 1000 watt inverter information

Which is better solar inverter or regular inverter?

There is very little difference between solar and regular inverters. They both do the same thing, which is convert DC power in AC for home appliances.

What does an inverter do?

An inverter chops up straight line DC voltage into pulses and then adjusts the height of each pulse so that the overall shape is like the sine wave associated with AC power from the utility grid.

The square pulses are then shaped so that the wave form is smoother. The more expensive inverters are called pure sine wave type and they have more smoothing electronics than the less expensive modified wave form inverters.

What is an inverter and why is it needed?

An inverter converts the DC power generated by solar panels and changed it into the AC power needed by home appliances.

It’s a very efficient way of converting and using the power output of home solar power systems.

Why is it called inverter?

The name comes from the way that the old rotary machines were used to convert AC power to DC. If the connections were reversed, these machines would then change DC to AC – the mode of operation was ‘inverted’.

How much does it cost to replace solar inverter?

Solar inverter cost for a medium-sized home solar system costs between $0.08 and $0.32 per kW. A good average price to work on for a good quality solar inverter is about $0.27.

An inverter for a home solar system rated at 5000 watts would cost between $1000 and $1500 ($1350 average.)

What’s the best solar inverter?

The best solar inverter is a pure-sine wave model. There are many good quality brands, such as Victron, Xantrx, Powerbright and Renogy.

Modified sine-wave inverters generally have less/lower quality electronics for wave-form shaping and can buzz. They also can interfere with household electronic devices and cause some motors to overheat.

How do solar panels work for your home?

Can you walk on a solar roof?

Yes, solar roof tiles are designed to  take the same weight as normal roof tiles, if not more.

What size solar panel do I need to run a TV?

A 50 inch LED TV consumes about 60 watts per hour, so a 100 watt solar panels in full sunlight should run it.

If the TV is going to run in the evening or at times when the sun doesn’t shine, then a 50Ah battery is recommended as well.

How many amps will a 100 watt solar panel produce?

Source: What size 12V solar panel do I need?

Solar power for homes

Do solar panels Increase Home Value?

According to Zillow the average value of a US home increases by about 4% after solar panels are installed.

Do solar panels make it harder to sell house?

No, solar panels make it easier to sell a house. Once a solar installation is paid for electricity is free, so a portion the future electricity savings are reflected in the house price.

As a general rule, a house price imncreases by about 4% after a solar installation.

How many amps does a 300W 12v solar panel produce?

The maximum amps of a 300 watt solar panel is called Imp (Current at Maximum Power) and is provided on the specification sheet by the manufacturer. An average current is 9.5 amps DC for a 300 watt solar panel with Voc 42 volts. The equivalent AC appliance current (USA) is about 3 amps.

Source: https://www.solarempower.com/blog/what-can-300-watt-solar-panel-run/

Solar energy facts

How many amps does a 350 watt solar panel produce?

A 350 watt solar panel with nominal supply voltage 0f 24V can produce about 9 amps of current.

The optimum current depends on the irradiance for any given location and also the internal resistance of the load.

MPPT controllers should be used as they are designed to match the panel Characteristic Resistance and track the Maximum Power Point.

How many amps will 400 watt solar panel produce?

The electrical specifications for a typical 400 watt solar panel might be:

• Max Power at STC: 400W
• Max System Voltage: 1000VDC
• Optimum Operating Voltage (Vmp): 72.9V
• Open Circuit Voltage (Voc): 85.3V
• Optimum Operating Current (Imp): 5.49A
• Short-Circuit Current (Isc): 5.74A

SOLAR BATTERIES FAQ

How many batteries do I need for a 2000 watt solar system?

A 2000 watt solar system with irradiance of the US average of 4 peak-sun-hours per day generates:

2000 watts x 4 peak.sun-hours = 8kWh

Using 12 volt batteries:

Battery amp-hours (Ah) = 8000 watt-hours / 12 volts = 666Ah

4 batteries rated at 200Ah would be required.

How many watts solar do I need to charge a 12V 200Ah battery?

As a general rule, a 200Ah lead-acid deep-cycle battery would need a 300 watt solar panel to fully recharge from 50% Depth of Discharge (DOD) assuming 4 peak-sun-hours per day. Charging would be complete in one day with a clear sky.

How many batteries do I need for a 300 watt solar panel?

The average energy output of a 300 watt solar panel is:

4 peak-sun-hours x 300 watts = 1200 watt-hours

So this is the maximum charging energy available each day.

Assuming you’ll be charging a 12 volt battery, then charging amp-hour capacity supplied from the panel:

1200 watt-hours/12volts = 100Ah

Assuming this amount would also be discharged overnight, then the following battery capacity would be required for a 300 watt solar panel setup:

• Lead-acid deep-cycle battery @50% DoD= 200Ah
• LiFeP04 battery @80% DoD = 125Ah

How many solar panels does it take to charge a 12 volt battery?

A 12 volt 50Ah auto battery discharged to 20% will take 2 hours to recharge using a 100 watt solar panel. (MPPT controller recommended.)

A 12 volt 100Ah deep-cycle lead-acid battery discharged to the recommended 50% will take 10 hours to charge using a 100 watt solar panel. (200 watts solar and MPPT controller recommended.)

A 12 volt 100Ah LiFeP04 battery discharged to the recommended 80% will take 16 hours to charge using a 100 watt solar panel. (300 watts solar and MPPT controller recommended.)

How long does it take to charge a 12 volt battery with a 100 watt solar panel?

See previous question.

Can a solar panel overcharge a battery?

Even a small solar panel can overcharge a battery if left directly connected . Always use an MPPT charge controller, unless the solar panel is less than 2 watts.

Can I connect solar panel directly to battery?

As a general rule, never connect a solar panel directly to a battery. It can overcharge and damage the battery internally.

Always connect through a solar charge controller, either PWM or MPPT type. The only exception is if the solar panel is so small that it’s maximum output equals the float charge value of the battery.

Some commercial battery maintainers are designed to operate directly connected and can be left connected.

Will a 20 watt solar panel charge a battery?

A 12 volt 20 watt solar panel will charge a battery at a slow rate, but shouldn’t be directly connected. Use a solar charge controller at all times.

Can you charge a lithium battery with a solar panel?

You can charge all types of lithium battery with a solar panel as long as you use a solar charge controller. Most charge controllers have settings for different types of batteries, such as AGM, GEL, LiFeP04 and li-ion.

Can a 20v solar panel charge a 12V battery?

A solar panel with nominal working voltage of 20V can charge a solar panel but it is essential to use a charge controller.

An MPPT solar controller will track the Maximum Power Point of the panel, set the charge voltage of the battery and convert the extra voltage into more charging current.

How many watts can a 40 amp MPPT charge controller handle?

The watts that a 40 amp MPPT controller can handle depends on the output voltage. Some have a variable setting and automatically adjustson connection:

• 40 amp MPPT controller with 12 volt battery = 12 x 40 = 480 watts
• 40 amp MPPT controller with 24 volt battery = 24 x 40 = 960 watt

Solar panel installation

How solar energy can be stored?

Solar energy can be stored in a variety of ways, such as heat or even mechanical flywheels, but by far the most common is to used deep-cycle batteries.

This is the basis of home off-grid solar power systems. Batteries can either be lead-acid (deep-cycle type) or lithium technology, which are inherently deep-cycle.

Lead acid deep-cycle batteries can be discharge to 80% (50% recommended for long life) while lithium iron phosphate to 95% (80% recommended.)

How Long Can solar power be stored?

All types of batteries have a natural rate of discharge when not in use. For Lead-acid batteries this is about 5% of the total capacity per month.

Is storing solar energy expensive?

Off-grid solar power systems use lead-acid or lithium batteries to store the solar energy for use at night or during periods when the panels are shaded due to poor weather.

The average cost of an off-grid home solar power installation is about $15000 and energy storage batteries may account for 25% to 30% of this cost.

Are solar battery storage worth it?

Solar battery storage is worth it from several points of view:

1. Solar battery storage enables a home to go off-grid, which means no electricity bills
2. Solar battery storage kicks in when there is a power outage, so you’ll have power for some days
3. A grid-tie system will use solar battery energy storage at night instead of the power grid

Can a battery power a house?

Yes, a battery or rather, a bank of batteries can power a house. This is exactly how an off-grid home solar power system operates.

During the day the solar panels power the house and also charge a solar energy storage battery bank which typically has a capacity of hundreds of Ah.

At night-time, or on cloudy days, the battery takes over and powers the house. The bank of batteries may be lead-acid deep-cycle or lithium iron phosphate.

Are battery backups worth it?

During the recent Texas power outages many homes were without power. Battery backups are worth it because they can power a home during power outages, which is very convenient.

How long can a solar battery power a house?

How long a solar battery can power a house depends on its capacity and the energy consumption of the home.

Average US energy consumption is 33kWh/day, a battery of similar capacity would be need to power a home for a day.

A 33kWh in Ah is determined by the voltage, typically 48 volts.

33000 watt-hours/48 volts = 687Ah

How long can a Tesla powerwall power a house?

Tesla Powerwall 2 has a capacity of 14kWh, so it’s a simple calculation to work out how long it could power a home with an average energy consumption of 33kWh/day.

Time to supply 33kWh home = 24 hours x 14/33 = 10 hours

You would need 3 Tesla Powerwalls to power this home for 24 hours.

Can a Tesla powerwall power a home?

See previous question.

Can you go off grid with Tesla powerwall 2?

You can now go off-grid with Tesla powerwall 2. The number of batteries required depends on the home’s energy consumption and the number of hours autonomy required i.e. overnight or a couple of days.

How long will Tesla powerwall 2 last?

Powerwall 2 is guaranteed for 10 years with unlimited charge/discharge cycles, which is pretty impressive. With limited discharge levels (80%) Powerwall 2 will last much longer than that but the caapacity may diminish as the years pass.

ELECTRIC CAR FAQ

What if your Tesla runs out of power?

A Tesla EV running out of power is much rarer than you might think. Warning signals are given as you approach 10% battery capacity and some functions may shut down to conserve power.

If you continue to drive until the battery is empty, the Tesla will go through a safety shut-down procedure and slowly come to a halt.

A Tesla cannot be towed, it has to be taken away on a truck or trailer.

Can you jumpstart a Tesla?

No, you can’t jump-start a Tesla. It either needs to be taken on a truck to a charging station or partially charge to drive it to a station.

What to do if EV runs out of power?

Don’t try to tow an EV if it runs out of power. It may become damaged.

It should be loaded on a truck and taken to a charging station. Some emergency roadside services are now carrying charging packs to get a stranded EV moving again.

Should I charge my Tesla every night?

How regularly you charge your Tesla depends entirely on your daily mileage. The average US commute is just over 30 miles, so twice a week should be sufficient.

It doesn’t hurt to top it up every night

Does Tesla increase electric bill?

You can expect to pay between $15 to $60 extra per month to charge your Tesla.

The exact amount depends on your daily mileage, how you drive, if you use the AC or heater and how much you electricity costs.

Do electric cars charge while driving?

No, electric do not cars charge while driving. EVs are designed to charge from an AC source and it isn’t possible to charge them direct from solar panels, for example.

It sounds a great idea to have a car covered in solar panels so it can drive forever, but it doesn’t work like that at the moment.

Do electric cars lose charge when parked?

All batteries lose charge if left standing for any amount of time. Lead acid bateries lose about 5% a month, while lithium-based EV batteries will lose about 4% each month left standing.

What is the lifespan of an electric car?

Like most mechanical and electrical machines the answer is heavily afected by the way it is driven and maintained.

Modern electric motors are good for between 8 to 10 years, while the battery pack would need changing eveyr 5 to 7 years.

The rest of the car could go on for 20 years.

How long is a fast charge for an electric car?

While the slowest charge (Level 1) can take many hours to recharge an EV, the fastest chargers can now recharge the battery up to 80% full in 20 to 30 minutes.

How long would it take to charge an electric car with a solar panel?

As a general rule, 10 solar panels rated at 300 watts each will be required to charge a Tesla electric vehicle if the daily mileage was around 30 miles, which is the average commute distance in the USA. The energy needed is about 6kWh, representing about 6.5% of A Tesla S 85kWh battery.

The car would be charged in 5 hours.

Source: How many solar panels to charge a Tesla?

How much does it cost to fully charge an electric car?

At an average electricity cost of $0.13 per kWh it would cost about $9 to charge the average EV from empty to full (66kWh battery).