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A Buyer’s Guide For Used Solar Panels

Is there a market for used solar panels? you ask. You would be surprised. The adage ‘one person’s trash is another man’s treasure’ holds true for used solar panels too.

There is a thriving market for them in America and many other parts of the world. The demand for used solar panels comes from resellers or exporters, from individual buyers looking for a cheaper second-hand deal, and from those who practise off-grid living. When times are hard, people favour used solar panels over brand new ones even more.

The problem with used solar panels is the risk of buying damaged goods. However, taking the right precautionary steps will help reduce this risk.

In this article, we explain why there is still value in used solar panels and what you should look out for when purchasing them.

What Is The Value Of Used Solar Panels?

Second-hand modules are sold according to cost per watt as this is the most standardised way of pricing them, similar to how the prices of new solar panels are compared. As of 2021, the price of a used solar panel can be as low as only $0.10 per watt. Even at $0.60 per watt, used solar panels are easily snapped up.

The low price does not mean that the photovoltaic (pv) panel is at the end of its lifespan. No doubt, the older the panel is, the lower its efficiency level will be and thus its cost. Most used solar panels for resale are aged between 1 and 9 years. These still operate at a high efficiency rate.

The value of used solar panels also lies in the materials used to make the solar cells. Photovoltaic cells contain elements such as silver and tellurium. These are rare and non-renewable resources which can be extracted from the used solar panels.

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A strong market exists for used solar panels outside of America. The demand goes as far as Africa, Asia and Europe. According to the International Renewable Energy Agency, there are already thriving online platforms in Europe for the resale of used panels. For example, www.secondsol.de and www.pvXchange.com.

Is Buying Used Solar Panels Worth It?

Let’s face it. A brand new solar power system is expensive. No doubt the latest photovoltaic technology can generate twice the power of used ones.

However, new models naturally come with a price tag at least double the cost of used ones. Even with the reducing cost of new solar panels each year, it still can’t beat that of used panels.

The efficiency rate of a used solar panel is definitely lower than a new one. The reduced efficiency is caused by impurities creeping into the crystals of the photovoltaic material. Some of the electrons generated are attracted to these impurities instead of flowing into the electrical circuit.

A solar panel loses between 0.5 and 0.8 percent efficiency per year. Sooner or later, the panel will become completely dysfunctional. However, even with a 0.5 percent efficiency loss per year, a solar panel is still operating at 86 percent after 30 years.

For the thrift-seeker, used solar panels are a lifesaver. Some people even buy enough used panels to cover their roofs. This makes sense when there is an existing solar system and you’re just switching out the panels on your own.

The cost of the panels constitutes a relatively small part of the entire solar system installation. According to NREL, solar companies are charging around $2.60 per watt to install rooftop solar systems. About 63 to 91 cents of that go to making and delivering the panels.

Some buyers get only one or two used solar panels to charge a battery for their RV, or to power the lights of a shed. Used solar panels are ideal for small projects where you might want to keep costs low. A large number of off-gridders also favour used solar panels because of the cost and because they want to reduce the environmental impact of discarded solar panels.

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Considerations When Buying Used Solar Panels

1. Does The Used Solar Panel Work?

Whenever possible, test it before buying. To do so, you will need good, clear skies and a volt/amp meter. If it passes the two tests below, it should work.

First, do a simple voltage test to see whether the panel produces the voltage listed on the original sticker of the product. If the sticker is gone, try to look up the information online. From there, you can compare its current efficiency rate against its new-state rate and decide whether you’re being offered a fair price.

The second test you can do is to gauge the panel performance in terms of DC amps. Configure your meter for DC then expose the panel to the sun for at least 5 minutes. You should get at least 80% of the LSC rating on the sticker.

2. Look For Damages Or Imperfections On The Used Solar Panel

A solar array exposed to all sorts of weather conditions might be damaged by rain, dust, small rocks and all sorts of debris. Check for cracks in the panel, signs of moisture underneath the cover and pv cell connections that are broken.

Even if the solar panel gives you a good reading, any visible damages will likely affect its longevity. Bear in mind that used solar panels don’t come with warranties.

Some damages are not visible, such as moisture build-up in the internal circuitry. This type of damage is more common with amorphous silicon panels.

If this problem exists, you will see fluctuations in the voltage output when you test the solar panel in the sun. These fluctuations may mean that the solar panel doesn’t work properly. 

Sometimes the used solar panel may not have any imperfections except looking brown. This often occurs with older solar panels that are made from plastic substrate. A brown panel can still be efficient.

Another common issue with used solar panels is burned out bypass diodes. However, this problem can be easily fixed and you can get a really good bargain for this type of ‘damaged’ goods.

Lastly, there is the problem of loose connection between pv cells in the panel. The connections can be fixed by soldering them.   

3. Can You Do The Installation Yourself?

This is important because it can be hard to find a solar installer for second-hand solar panels. Some solar installers are reluctant to do the job when they don’t know the source and efficiency of the equipment. If you don’t know how to DIY and you can’t find someone to help, you might be better off getting a new solar installation.

4. Check The Seller’s Credibility

To reduce the risk of a bad purchase, you should only buy from a seller with an established credibility as a repairer. Alternatively, the seller should be able to guarantee the product is on par with generally accepted safety parameters, such as the IEC 61730 international standard. The standard indicates that the product has been tested for general inspection, electrical shock hazard, fire hazard, mechanical stress and environmental stress. 

The seller would have already carried out quality control tests, measure amp and voltage performance. The results would be documented in writing. 

Some sellers can also verify whether the manufacturer’s warranty will transfer with the purchase.  If the manufacturer’s warranty no longer applies, some sellers can offer a third party warranty.

5. Is The Seller Reputable?

Reputable resellers often come with success records and recommendations that can be easily found online. They would have professional websites, Google business listings and social media profiles. 

Some have positive reviews from customers and tend to be members of trade associations and/or chambers of commerce. In America, they may also be rated by the Better Business Bureau.

Many resellers list products for sale on third party online marketplaces (such as eBay and Amazon), clearing houses or exchanges. You can further reduce risk by reviewing the screening parameters of these marketplaces. 

There are marketplaces and exchanges which are open to anyone, and do not offer any liability. There are also those that are exclusive to registered solar companies which meet member qualifications and come with business references.

To protect yourself, you should read all the Terms & Conditions before buying on an online marketplace. Look out for hidden transaction fees, which should be stated in the Terms & Conditions.

Lastly, if you are looking for a used solar panel as a replacement part, check with your insurance agent first. Some insurance companies may have connections to reputable repairers so that you can install the used solar panel safely and with the least financial consequence to you.

Conclusion

Used solar panels can be found in the secondary solar market and in online marketplaces. As photovoltaic technology improves, so will the demand for used solar panels. You just need to do the relevant homework before buying them. 

The tests and checklist in this article are relevant to individuals considering used solar panels for their home and resellers looking for a used solar panel stock. 

If you are purchasing for personal use, you should keep in mind that renewable energy tax credits are not extended to used solar panels.

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