How To Maximize Solar Panel Efficiency

Let's say you bought a solar panel. The electric bill's going down and you're happy with the results.

But does that mean you always maximize the savings from your solar panel?

Not really. And in our opinion, it’s best if solar investors learn how to maximize solar panel efficiency so you can earn your money back quicker and increase those savings. 

"Why?"

Well, it’s no secret that solar panels or Photovoltaic (PV) systems are expensive. That’s why not everyone can immediately decide to invest in them.

But despite the initial investment, plenty of compelling reports indicate that you will get your money back in 3-12 years, depending on where you live.

With solar panels averaging a lifespan of 20-25 years, this means that you are guaranteed to get 100% of your money back—with interest.. It's just a matter of when.. There are also plenty of online tools available that can help you determine the solar potential in your area.

Month Solar Radiation
  (kw/m²/day)
AC Energy
  (kWh)
January 3.70  362
February 4.11  367
March 5.66  540
April 6.79  628
May 7.04  667
June 7.40  664
July 7.03  651
August 6.48  598
September 6.22  548
October 5.13  482
November 3.98  370
December 3.20  318
Annual 5.56  6,195

However, one thing you should know about cost analyses  is that professional organizations assume your solar panel system is optimized to produce maximum power.

Not maximizing the rated PV capacity could lead to delays in your payback period and overspending for a suboptimal PV.

This is why we think solar panel owners should learn how to maximize solar panel efficiency.

What is Solar Panel Efficiency

Before we share our insights on how to maximize solar panel efficiency, we must first ask ourselves “What exactly is that?”.

According to IEEE, Solar Panel efficiency is

"The ratio of available electric power output to total incident radiant power intercepted by the area of a panel composed of solar cells."

A lot of you might be thinking:

"Huh?Too nerdy, didn’t read. How am I supposed understand that?"

Don't worry, we agree with you.

In simple terms, solar panel efficiency is the ability of a PV panel to convert potential solar power (the irradiance coming from the sun) to electric power.

So, for example, if a 200W PV panel has a 22% efficiency, it means that during peak power production, the 200W of electric power is only 22% of the available solar power from the sun.

Another way to describe solar panel efficiency is through practical operating and installation techniques.

Most people take this for granted, resulting in poor panel power output. And most of the time, manufacturers get blamed for well-made solar panels with poor placement and installation.

Best Ways to Maximize Solar Panel Efficiency

So what are the best ways to maximize solar panel efficiency?

Let's break it down into two (2) sections:

First you have to pick a quality solar panel with features that increase efficiency. More on this in the following section. After which, we will share with you the best solar operating practices to further optimize their efficiency.

With that, let’s look at some of the recent PV cell innovations that contribute to high solar panel efficiency.

Know Solar Panel Features and Quality

Type of Cell: Pick C-Si

There are various solar cell technologies today competing in the green energy market.

Right now, crystalline-silicon (C-Si) solar cells dominate the market mainly due to their low $/watt and substantial efficiency.

However, solar developers consider other cell technologies, such as Cadmium Telluride (CdTE) and Copper-Indium-Diselenide (CIS), depending on the application and suitable environmental parameters.

Bottomline, C-Si is currently the best choice for residential PV systems. However, solar developers are exploring other module types that may outperform C-Si in specific applications and environmental conditions. You can expect these PV modules to compete with C-Si someday when they fully mature.

PV Cells: Polycrystalline vs. Monocrystalline using PERC Technology

Okay, now we know C-Si is the best choice for you. But, as you browse through e-commerce sites, you will most likely encounter the two most popular cell types out there: Polycrystalline and Mono-Crystalline.

"So, which one should I pick?"

It depends on your budget and specific needs. Let's go through each type and then make a conclusion at the end of this section.

solar panel material - Growatt
Mono-crystalline

Mono-crystalline panels are well-known to have higher efficiencies, leading to small space usage and portability compared to others—the efficiency of mono-crystalline ranges from 17% to 22%.

This is the most popular cell type manufacturers use for on-the-go solar panels for camping or outdoor adventure.

Mono-crystalline is also known to last longer than the other C-Si types, but all these benefits come at a hefty cost

Polycrystalline

We said at the beginning that PV systems are expensive. Therefore, it is no surprise that PV inverters will develop a variant  focusing on affordability.

This is where polycrystalline truly shines. It has a lower efficiency ranging between 15% to 17%, but this technology is cost-effective and more sustainable to produce. It is best for residential solar rooftop systems or RVs.

Bonus: Choose PERC Cell Technology

PERC stands for Passivated Emitter and Rear Cell technology. It is a mature cell architecture that boosts solar panel efficiency by increasing solar radiation absorbed by the cell.

There is no reason for companies to use this technology without moving the price much since PERC cells don't add massive delays or expenses to manufacturing.

Bottom line, if you want to maximize solar panel efficiency, buy mono-crystalline panels that have PERC cell technology.

PV Cells: Full-Size vs. Half-Cut

Another innovation you should consider in maximizing solar panel efficiency is half-cut or half-size split cells.

Half-cut cells are precisely that: PV cells that are cut in half.

Top manufacturers recently pivoted towards split cell technology rather than full-sized square cells for increased PV panel efficiency.

How To Maximize Solar Panel Efficiency -Growatt

Adopting the split cell configuration for PV panels lowers resistive losses through busbars since  each split cell now operates at half the current.

Recall the power loss formula:

P(loss)=Current² * Resistance

Lower resistive losses also mean less heat dissipation which helps mitigate hot spots on the panel.

Lastly, embracing the split cell configuration leads to twice the busbar count, resulting in more busbars in operation despite shading or cloud cover.

So when buying solar panels, look for ones with half-cut PV cells to maximize efficiency.

Standard Busbars vs. Multi-Busbars

Busbars are the thin silver-colored wires you see running through your PV cells. Busbars have two main functions:

  1. They serve as the main highway for the current produced along smaller silver metallic wires known as fingers.
  2. They interconnect the front of a PV cell to the back side of another adjacent PV cell to form the whole PV panel circuit.

Typically, each PV cell would have 4 to 5 busbars. As manufacturers turn toward 9-busbar technology, expect PV cells to accommodate more current, leading to higher efficiency.

Also, more busbars mean more alternative pathways for current to pass through in case some of your PV cells experience microcracks, leading to higher panel reliability and resiliency.

Note: Microcracks occur when a panel experiences impact or heavy loads.

In summary, busbars serve as roads for electric current produced and interconnection between PV cells. Typical PV panels have 4 to 5 flat-wire busbars, but going with 9 round-wire busbars will give you more reliability and maximize solar panel efficiency.

Conclusion

Now you know the key features to maximize solar panel efficiency. If you had to pick one today, go with a 9-busbar, Half-cut, or Third-cut PERC Monocrystalline PV Panel.

If it is a solar panel for outdoor activities, look for portable solar panels that are lightweight and foldable.

Know the Best Solar Installation Practices

Solar installation practices sometimes fall under the radar when it comes to maximizing solar panel efficiency.

By this time, you are probably opening another tab to look for your high-efficiency panel. That's fine, but that is only half the battle.

Read on and learn how to maximize solar panel efficiency while avoiding overspending.

Planning your PV system

An underutilized solar panel is just as good as an inefficient one. That's why you need to determine what you want to power first.

Power

Say, for example, you are looking for a PV panel to power only a laptop and a cellphone. Planning to buy a solar panelshould look like this.

Table: Sample Case Study for Sizing a Solar Panel System

Item

Power Rating

Laptop

75W

Cellphone

15W

Total

90W

Based on the sample list, you are looking for a 110-120 watt panel. Buying a 90-100W for us is insufficient since it is highly likely that weather conditions will not produce maximum power everyday.

Pro tip: when planning to buy a panel, it is a good practice to determine your power load and include a buffer for less sunny days.

Energy

Now the next thing you should determine is how long and when can a solar panel power your electronics. For beginners, you should know that solar panels produce peak power production around noon (10 am to 3 pm) while operating at lower power during early mornings and late afternoons.  

How To Maximize Solar Panel Efficiency -Growatt

This means you can only power your electronics as planned for a specific period. People often face this advanced problem when diving deeper into solar panel systems.

Not having solar when you need it is unproductive.

So is there a solution available if you want to store your solar energy for on-demand use? Absolutely.

Energy Storage for Later Use

By now, we know that solar panels producing peak power are inefficient if not fully used. Not only that, you are at the mercy of when peak power production occurs.

This is a common issue most first-timers face when getting into solar panels.

How To Maximize Solar Panel Efficiency -Growatt

Energy storage systems (ESS) or Portable Power Stations (PPS) solve this problem.

"Huh? ESS? PPS? This is getting complicated!"

Relax. It's just a fancy term for a battery. We all know batteries are the "OG" of on-demand electricity. The most common ones are the 1.5V AA batteries we use for our remotes and the 12V lead acid batteries for vehicles.

However, ESS technology has grown leaps and bounds throughout the past decade in light of the commercial maturity of lithium-ion cells.

People who want to store electricity for later use purchase ESS or PPS attached to their solar panels.

However, the problem is that ESS could get expensive. For example, a 1.28kWh ESS can cost around $300-$500, while a 1.1kWh PPS falls between $900-$1100.

That is why it is essential to know how much energy you need.

How do we do that? It's simple. Know how long you intend to operate your appliances, then follow the energy formula:

Energy(Wh) = Power(W) * time use(h)

With this, we can expand the table we made earlier into something like this:

Table: Planning Your Power and Energy Requirements

Item

Power

Time Use

Energy

Laptop

75W

6 hours

450Wh

Cellphone

15W

3 hours

45Wh

Total

90W

 

495Wh

 

Given the results, we can conclude that you need at least a 100-watt solar panel and a 500Wh ESS.

By now, we have demonstrated that maximizing solar panel efficiency also depends on the following:

  1. What appliances will you use;
  2. When will you use them; and
  3. How long  

Set Expectations Based on Your Location and the Season

One of the major factors for solar panel output is where you live and its weather conditions.

This is why solar panels near the equator like South Africa, Southwest North America, and Australia produce more solar energy than ones at higher latitudes (e.g., U.K., Canada, Northeastern NA).

If you want to check how much solar energy is available in your area, feel free to use this solar map.

On top of that, weather conditions also impact efficiency but do not diminish solar production. That is why solar panels can still use indirect sunlight to produce electricity on cloudy days.

However, harsher weather like snow during the winter can fully cover solar, which can lead to no energy production. That is why snow removal equipment and maintenance plans are good if you experience snow in your area.

Tilt and Orientation

Solar panel tilt and orientation are primary factors for maximizing solar panel efficiency. Solar panels produce maximum power when placed perpendicular to the sun, but we cannot always move our solar panels to achieve this setup unless we buy a solar tracker.

Therefore, we recommend placing your solar roof panels facing true south with a tilt angle of 25 to 45 degrees for optimal electricity production.

Final Thoughts

There you have it! The best tips and advice to maximize solar panel efficiency. We know that some of these can be overwhelming, so we recommend getting help from experts and professionals when investing in a solar system.

Hiring experts for consultation while armed withthis knowledge will help you have peace of mind, a highly-efficient solar system, and more savings!