Low Wattage Solar Panels (How To Choose)

When it comes to solar panels, many people may mistakenly believe that bigger is better, and this is not the case – as it is with most other things in life. While you can get larger wattage solar panels, the lower wattage ones often make more sense from an investment and ROI perspective.

Solar panels come in various wattages, from as little as 3W to 500W, and most residential PV installations average between 290W and 320W. Lower wattage mobile or portable panels are used for smaller devices like mobile phone chargers, laptops, and wifi routers.

Let’s look at the benefits of using lower wattage panels in different applications :

  • Why lower wattage panels for your home could save you big money
  • What is solar panel efficiency
  • What do you use low wattage solar panels for
  • What’s the best wattage for a solar panel

Let’s dive into this now so you can better understand more about low-wattage solar panels and the benefits they can offer.

Engineer Holding A Low Wattage Solar Panel - Sol Voltaics: Solar Panel Information
Engineer Holding A Low Wattage Solar Panel

Why Use Lower Wattage Solar Panels For Your Home?

Opting for the lower wattage panels for your residential installation can save as much as 50% on the generation costs of your system.

When considering what size solar panels to install for your home, you also need to consider the generation cost. This is the cost per watt incurred, and you work it out by taking the dollar price for the panel and dividing it by the wattage to get the cost/watt.

Cost Per Watt

So, for example, a 320W solar panel priced at $200 would equate to $0,625 per watt, which is the generation cost you need to look at. This price does not include the installation, mounting, or connection costs.

If your solar array has ten panels and each panel is 320W at $0,63 per watt, that will cost $2016- 3200W @$0.63/W.

If you take a bigger wattage panel of around 400W at approximately $420, the cost per watt there is $1,05!

If you extrapolate that to the same generation capacity of 3200W, that would be eight panels, which will increase the generation cost to $3360, which is 67% more expensive for the same power.

That’s a fair whack of cash overspent, and that money saved can be used for other components and installation.

Picking The Best Wattage Panel For Your Home

As you’ll see when we look at panel efficiency, and as we’ve seen from the cost per watt, the bigger wattage panels are not always the best option, so you need to have that discussion with your installer or supplier when the energy requirement assessment is done.

The wattage and quantity of the panels you require will depend on the size of the system and the roof space available to determine the size of the panels required. It will also depend on the existing roofing structure and whether it can take the weight of the array.

So smaller wattage panels which are generally lighter, may work to distribute the weight of the array evenly and put less strain on the roof than larger, heavier panels would.

Another factor to consider when looking at low-wattage panels is their efficiency. Using panels that aren’t efficient will mean more panels and more money, with less generation capacity- and this applies equally to high and low wattage panels.

Why Is Solar Panel Efficiency Important?

The capacity and ability of solar panels to generate electricity are relative to how efficient they are at generating power using the available solar energy.

Modern-day solar panels have an efficiency of between 15% and 22%, improving all the time as technology develops. So whether you have eight 400W panels at $1.05 /W or ten 250W panels at $0.63/W rated at 22%,  you still get the same efficiency and generation, just at a lower price.

The highest efficiency of any panel is just under 23%, so most solar panels will be in the 20%-22% efficiency range.

Small Solar Panel In A Garden
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Where Are Low Wattage Solar Panels Used?

Low-wattage solar panels can have as little as 3W power generation, and these are typically used to trickle charge batteries that power small low voltage devices.

These panels are much smaller than those found on a residential PV array roof and are usually portable and easy to pack and store in vehicles, campers, and RVs. They can have their stand or simply be laid out on a table or roof of a car or trailer to generate electricity.

They don’t require an inverter, and low wattage panels like a 3W-10W are often used as trickle chargers for 12V batteries powering electric fences, vehicle batteries, or electric gates.

Even 10W panels are used for this purpose as they simply don’t generate enough current to power devices, even a mobile phone. Still, they are pretty efficient as trickle charges to maintain larger batteries’ voltage and current levels.

As the panel gets bigger, they can be used to provide power rather than acting as a trickle charger. A 20W solar panel can power small devices such as cellphones, LED lights, security cameras, and mini-pumps.

From 50W upwards, low wattage panels can charge batteries faster and power smaller devices such as DC TVs, laptops, LED lighting, and even small DC pumps found in camp showers.

You can even build an array of low-wattage panels connected to a charge controller and a battery to provide a source of AC power when outdoors, on a boat, or even at your home.

What Is The Best Wattage For A Solar Panel?

This is going to depend on the application. For home or residential systems, solar panels are usually rated at between 290W and 320W, but you can get panels of 500W or more if necessary.

Larger wattage panels that are efficient can reduce the number of panels needs and are helpful where roof space is limited, and power generation capacity needs to be met. So, for example, when a home needs 3kW of power but only has enough space for six panels, 6 x 500W panels can be used.

Where space is not restricted, the maximum number of panels at optimum cost per watt can be used, and for mobile applications like camping, the wattage would again depend on the power requirements.

When it comes to low-wattage solar panels, the applications are vast and offer the user various wattage and efficiency options to best match their desired power results.

Resources

https://www.cleanenergyreviews.info/blog/most-efficient-solar-panels

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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