Do Solar Panels Produce Volts? (Calculations + Examples)

Solar panels produce volts when exposed to the sun. But, that is only part of the equation. Panels also produce amps. In most cases, panels are rated in watts. Watts are the result of the number of volts multiplied by the number of amps.

Solar panels are rated by the work they can do measured in watts. Watts is a calculated value based on the volts and amps the panel produces. The calculations for evaluating the power ratings of a panel are quite easy.

  • Volts.
  • Amps.
  • Watts.

Once you know the simple equations you can easily figure out the power qualities of any panel.

Solar Panel Close Up
Solar Panel Close Up

solar Panel Power Calculations (Watts)

There is one basic equation employed in calculating the power factors of any electrical device, including solar panels. Based on what you know about the panel, the equation can be manipulated to calculate other values.

The base equation is:
V x I = P

  • P = Power = Watts
  • V = Volts
  • I = Inductance = Amps = Current

Example 1

  • Volts of panel = 12.
  • Current of panel in Amps = 5.0
  • 12 Volts x 5 Amps = 60 watts.

Often the packaging of a panel will indicate the power rating and the volt rating. By modifying the equation you can calculate the current in amps.

The revised equation is :
P / V = I

Example 2

  • Watt rating of panel = 100.
  • Volt rating of panel = 24.
  • 100 watts / 24 volts = 4.16 amps.

By remembering this simple power equation, and doing a little math, you will be able to calculate the power values of any panel. These values come in handy when you need to determine if a panel will provide sufficient power for your project.

Volts

Solar panels produce Direct Current (DC) voltage. They can be built to provide nearly any DC voltage. The voltage of the panel is impacted by cell size, cell construction, number of cells, panel size, and panel wiring.

The result is panels from 0.5 volts to near 50 volts. Each volt range has a use. Not all voltages are appropriate for all applications.

How Many Volts Per Solar Panel – Volt Ranges

  • Micro or Mini = 0.5 – 5.0 volts.
  • Small = 6.0 – 12.0 volts.
  • Medium = 12.0 – 24 volts.
  • Large = Over 24.0 volts.

These ranges are not official designations. They are general terms for panels at various power levels.

What Voltage is the Right For Solar Panels?

Every electrical device requires a specific voltage to operate. Some devices are more particular than others. Electronic devices tend to need a specific voltage to operate properly.

Mechanical items, like motors, are usually more tolerant of voltage variations. It is advisable to stick as close to the voltage specified by the device manufacturer.

Too great a voltage variation can damage or destroy a sensitive device.

Voltage Variations Can Cause:

  • Failure to operate.
  • Poor operation.
  • Overheat of device.
  • Damage to the device.

Micro and Mini Solar Panels

These panels are usually designed as substitutes for alkaline batteries. Therefore, they tend to produce voltages in multiples of 1.5 volts.

The size of these panels ranges from a few square inches to 30 or 40 square inches. Amp ratings are usually in the milliamp ranges.

They are generally used for small electronic devices. The panels themselves do not have frames but are framed by the device they power. Power ratings do not usually exceed 2 watts.

Micro/Mini panels are used in devices like:

  • Calculators.
  • Small portable radios.
  • AAA, AA, C, D sized battery chargers.
  • Small toys.
  • Garden lights.

Small Panels

Panels in this group are used to drive larger electronic devices and small motorized devices. These panels are usually no larger than One Square Foot in size. Amp ratings are still quite small, usually not exceeding one amp.

These panels may come independently framed or framed within the device they power. Power ratings are around 5 watts.

Small panels are used for items like:

  • Larger radios or Bluetooth Speakers.
  • A small pond or fountain pumps.
  • Car battery tenders.
  • Security lights.

Medium Panels

Panels in this range are what we envision as domestic solar applications. They are up to 3 feet by 5 feet in size. Frames are aluminum.

Panels are generally mounted on roofs or pole-mounted arrays. Current ratings on these panels can approach ten amps. Power ratings rise as high as 250 watts.

Medium panels commonly supply power to:

  • Grid-tie homes.
  • Off-grid cabins and home.
  • Well, pumps.
  • Utility and outbuildings.

Large Panels

With the introduction of Maximum Power Point Tracking (MPPT) charge controllers, off-grid solar arrays were able to implement higher panel voltages.

Instead of the array being limited by the battery bank, the MPPT controller would step the higher voltage down to match the battery bank and increase current.

Large panels are now put out in excess of 30 volts and 300 watts of power. The size of these panels is nearly 4 feet by 6 feet.

Large panels can be used for:

  • Larger grid-tie systems.
  • Large off-grid homes.
  • Industrial arrays.

Different Voltage Ratings on a Panel

Every solar panel has three-volt ratings. The nominal voltage is the circuit voltage the panel is designed for. The Volts at Maximum Power (Vmp) is the voltage the panel will produce under ideal conditions.

This value is essentially the maximum working voltage of the panel. The third voltage value of a panel is the Volts at Open Circuit (Voc). This value is the amount of voltage the panel can produce under ideal conditions with no load.

To estimate different voltages:

  • Nominal is circuit voltage = 12, 24, 48 volts
  • Vmp voltage is Nominal + 45% of nominal.
  • Voc voltage estimate is Nominal + 80% of nominal.

Current = Amps

The force known as current is expressed as amps. The amps produced by a solar panel are a function of the material used, the area of the panel, and the way the cells within the panel are wired.

Individual solar cells produce approximately 200 milliamps per square inch. Panel current can be increased by wiring cells in parallel rather than in series.

Amp Factors

  • Cell materials.
  • Cell size.
  • Number of cells.
  • Cell connection pattern.

Amp production by solar panels ranges from a few milliamps in the micro and mini panel category to 10 amps from the large panels.

A device will only draw the current it requires. When choosing a panel, be sure the current produced is sufficient to operate the device.

Using a panel that produces a lot more current than required is a waste of space and money.

Volts – Amps – Watts

Volts, amps, and watts are all factors we must consider when choosing a solar panel. Based on the requirements of your application, more volts may be more important than the current produced. In other cases, watts are all that matters.

Be sure you understand the power requirements of your situation before you choose a panel. A mistake can cost you time and money you would rather not spend.

Sources

General Solar Panel FAQ

What Problems Do Solar Panels Solve?

In environmental terms, solar panels can potentially solve a handful of problems, including;
1. Air pollution
2. Water pollution
3. Greenhouse gases
4. Reduction in fossil fuel use

For individuals, solar energy allows you to become completely self-sufficient when it comes to your electricity needs and can save you a lot of money in the long run.

What Are 3 Important Uses Of Solar Panels?

The three most important uses of solar panels are;
1. Solar electricity. This can be used to power almost any appliance in your home, including TVs, computers, and fridges.
2. Lighting. In addition to the use of low-power, LED lightbulbs, solar panels can provide an efficient, low-cost, and environmentally friendly way to provide lighting to homes. 
3. Portable solar. In our modern, always-connected lives, our phones, tablets, and computers are almost always with us, and all run on batteries. Portable PV chargers can help keep our batteries topped up no matter where we are, as long as there is some sun to charge them.

Do solar panels give you free electricity?

Once the cost of the array is paid in full, the energy it produces is free. There are ongoing maintenance costs, too, such as annual panel cleaning, etc. 

How much will my electric bill be with solar panels?

Suppose your solar array includes a solar battery backup system, and it is large enough to fully cover your energy usage per day. In that case, your monthly electric bill will be next to zero dollars, even with a grid-tied system. 

If your solar array does not include a solar battery backup system, then at night, your house or business will use grid electricity. That cost will vary but expect to pay from 1/3-2/3 of your average electric bill, and that cost will fluctuate seasonally. 

Do you save money with solar panels?

The simple answer is, Yes, you save money with solar panels. There is an initial upfront cost, but since solar panels are warrantied for 25 years, you will save money over time. You will also begin to see monthly savings in energy bills, but there are other ways that solar panels pay you back. Those include:
1. Adding value to your home or commercial building 
2. Monthly decreases in energy costs
3. The ability to add more energy appliances without increased monthly costs
4. The potential for tax credits for going solar

Can solar panels power a house 24-7?

Most definitely! Solar panels can certainly power a house 24-7, with the addition of a high-quality inverter and a suitable battery bank, of course. To power, a house under normal usage will require a massive solar array, though, and there will be a very expensive initial financial outlay.

Do I need to tell my energy supplier I have solar panels?

This depends on where you live, but in most cases, it’s not necessary to inform your energy supplier that you have solar panels. That said, you may be producing excess power with your solar system, in which case you may be able to sell that excess power back to energy companies.

In this case, you’ll naturally need to be in contact with them. 

What Are Solar Cells Known as and Why?

Solar cells are also called photovoltaic (PV) cells. They are called so because the term ‘photovoltaic’ literally means light i.e. photo and electricity i.e. voltaic.

These cells generate electricity through the photovoltaic effect. This effect basically causes the generation of free electrons from the semiconducting silicon material of the solar panel when sunlight hits its surface.

What Type of Solar Panels Are Most Efficient and Why?

There are currently three types of solar panels available in the market that are:
1. Monocrystalline
2. Polycrystalline
3. Thin-filmed

Among these, monocrystalline solar panels are known to be the most efficient among all others.

Does heat enter your home through the roof?

Absolutely. Heat enters your home through your roof, and on a hot day your attic can get up to 150 degrees Fahrenheit or more. Through conduction, heat from the sun warms your roof which then warms your attic and the rest of your home.

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