Best Solar Panel for Cloudy Days (Generate Maximum Power)

In this article, you will learn about the best solar panel for cloudy days including the key features to increase performance. 

There’s no denying that solar panels perform best in direct sunlight. You can’t control the weather so we all encounter cloudy conditions. Just because it’s overcast doesn’t mean you don’t need to generate electricity. 

If you’re planning to install solar panels on a vehicle or building, you’ll need to charge batteries and run appliances wherever the weather. Even if it’s a cloudy day, you can still take advantage of solar energy but performance will vary dramatically depending on your equipment. 

The big thing is to use efficient panels and keep them very clean. I can still run completely from solar power and batteries even on a cloudy day in winter” explains Andrew from Dinky Coffee, a solar power coffee van.

Below we will discuss what sets apart the great solar panels from the bad and the top product available.


What to Look for in a Solar Panel for Cloudy Days?

You probably already know a little about solar panels, so let’s avoid the generalist information. There are three key things to take into account when looking for a solar system that performs best in cloudy conditions.

High-Efficiency Monocrystalline Cells

You need to use a solar panel with the highest conversion efficiency. This is the amount of sunlight the cells convert into electricity. Currently, the highest level of efficiency available is between 20% – 24%. This is achieved using monocrystalline solar cells. 

monocrystalline solar cells
Dark black monocrystalline cells

Choose a solar panel with monocrystalline cells with a conversion efficiency above 20%. Avoid other options like polycrystalline or thin-film solar panels which have low efficiency. 


By-Pass Diodes

With cloud cover, you can also run into another issue of hot-spotting or partial shading. This is when one part of the panel is in direct sunlight and another part is shaded by cloud cover. 

By-pass diodes are wired into the PV module and provide an alternate current during partial shading. It stops the high current in a cell exposed to direct sunlight from overheating a shaded cell with a lower current. 

All modern solar panels should have by-pass diodes included as standard.


Power Output

If you’re expecting regular cloud cover then it is a good idea to upsize your system. Even with an efficient solar panel, you might only generate 30% output on a cloudy day compared to a sunny day. This means you’ll need a bigger array to make up for this lower power output. You might consider doubling or tripling the wattage of your solar panel to make up for these losses. For example, if you want to generate 100 watts on a cloudy day, you’ll need at least 300 watt solar panel systems. 


Best Solar Panel for Cloudy Days

Now you understand what features to look for, we can go through the best solar panels for cloudy conditions. All of the options below feature monocrystalline solar cells for maximum efficiency. 

Newpowa 100 Watts Monocrystalline Solar Panel

Kicking things off is this 100 watt option from Newpowa.

It’s perfect for what we are looking for with new monocrystalline cells packed into an aluminum frame and covered with tempered glass. This gives you a two fold benefit of enjoying excellent efficiency and incredible durability. 

You could happily use this on an RV or boat for decades without a problem. In fact, it comes with a 25-year power output guarantee. Thanks to cell efficiency the size of the panel is reduced compared to competitors. This is awesome as it allows you to fit more of these panels into a smaller space. That’s very helpful to increase your power output on a cloudy day.

Pros:

Cons:

  • Not a complete kit (need to add charge controller)
  • Doesn’t work well with solar generators

WEIZE 200 Watt Solar Panel Starter Kit

If you want a complete kit that comes with everything you need to hook up to your deep cycle battery then check this out.

This system generates 200 watts output and has everything we’re looking for. Once again the high-efficiency cells are protected by anti-corrosive aluminum and reinforced glass. That keeps everything running smoothly even when driving down a bumpy road.

Included in the kit is a charge controller with cables and connectors to connect everything up. Adding to this you get z-bracket mounts and predrilled holes. This all means you can install and hook everything up really easily. 

The only drawback is that it is a PWM controller. For maximum efficiency in the cloud, you could switch this out for an MPPT option in the long run.

Pros:

  • Complete kit
  • Includes charge controller
  • High efficiency
  • Easy to install
  • Durable

Cons:

  • No MPPT controller
  • Will need to replace controller in the long run

Renogy 100 Watt Monocrystalline Portable Solar Panel

For a portable solar panel to use on cloudy days then this is a nice solution.

It’s built by Renogy who makes all manner of off-grid power solutions. Many portable solar panels fall down when it comes to performance as they sacrifice this to shed weight.

Here you still get high quality panels built using monocrystalline cells. Its design makes it easy to pull out and set up. Then you can hook it up to your batteries via the built in solar charge controller.

The kickstand gives you the perfect angle to absorb sunlight. This is handy on overcast days as you can increase efficiency and take full advantage of any direct sunlight that peaks through. You can even reposition it through the day to increase total output as much as possible. It gives you the flexibility to use solar power how and when you want, whatever the conditions.

Pros:

  • High efficiency
  • Kickstand angle
  • Easy to use
  • Includes charge controller

Cons:

  • PWM not MPPT controller
  • Heavy
  • Confusing instructions

Goal Zero Nomad 200 Watt Portable Solar Panel

The Goal Zero makes the list for its outstanding quality and huge power output.

With its whopping 200W capacity it will help you extract more energy when conditions aren’t so favorable. Then when the sun is at full strength you’ll go into supercharger mode. 

It’s designed to be used directly with the GZ portable power stations. If you add one of these ‘Yeti’ power banks you’ll have an awesome off-grid electricity setup. Plus, with the power station you won’t have to worry too much about cloud cover. You could also find adaptors to use the solar panel with other solutions too. 

Kickstand legs allow you to easily produce a nice tilt angle for increased efficiency from the monocrystalline cells.

Pros:

  • Very efficient all year round
  • 200W capacity
  • Works with Yeti power station
  • Tilt angle stand
  • Easy to use

Cons:

  • Need adaptor to use with other batteries/power stations
  • Expensive as made in USA

BougeRV 120W Lighter Portable Solar Panel

This BougeRV portable solar panel is a great candidate for your attention as it packs a unique blend of high efficiency and lightweight design.

The cutting edge design uses busbar solar cells which are smaller and thinner while still retaining a 23.5% conversion efficiency. This means you get a powerful panel at a reduced size and weight. Ideal if you want a portable solar panel for cloudy days that doesn’t weigh a ton.

It’s rated to 120 watts to give you a boost over common 100 watt briefcase solar panels. Again, this helps when the sunlight is erratic. Adding to this, it’s got everything you need including decent waterproofing in case there’s rain clouds about. A kickstand makes the setup super easy while a protective case allows for safe transportation. 

The only downside is that you’ll need to add your own charge controller and adapters. The BougeRV shop supplies all of these items to fit with the product.

Pros:

  • Lightweight
  • Smaller busbar cells
  • 23.5% efficiency
  • Easy to use and transport

Cons:

  • No charge controller
  • Limited degree angle on stand

520W Solar Wind Kit System with 120W Monocrystalline Solar Panel

Have you thought about incorporating wind energy into your electricity supply? This could make a huge difference when the sun is blocked out by clouds.

You can now get complete solar wind kits that give you a double energy source. This kit gives you a high-efficiency monocrystalline solar panel to generate upto 120 watts. On top of that, there’s an awesome 400 watt wind turbine. So when adverse weather is around you still get the benefit.

The hybrid charge controller is MPPT which further increases your battery charging efficiency from both sources. To top everything off there’s a 1000W power inverter thrown in too!

This is something to consider if you struggle for consistent sunshine.

Pros:

  • Complete kit
  • High efficiency solar panel
  • Wind turbine
  • MPPT controller
  • Unique solution

Cons:

  • Expensive
  • Wind turbine not good for moving vehicles
  • Low quality inverter (it is pure sine though)

Will a Solar Panel Work in Cloudy Conditions?

Yes, a solar panel will still work in cloudy conditions. This is because light will still reach the cells. Although direct sunlight is always best this does not make up all of the energy source that a solar panel can work from.

Photons of light will still pass through clouds and bounce off objects and the atmosphere to reach your solar. This type of indirect sunlight is known as diffuse light. Around 30% of a solar panel’s electricity production can come from diffuse light. 

This means a solar panel generates electricty on a cloudy day but power output will be dramatically reduced. You will need a highly efficient monocrystalline panel to try and counteract this problem. Even with the best options could still see energy production drop by 70%.


Solar Panel for Cloudy Days Summary

I hope this article helps you find the best solar panel for cloudy days. 

By now you should understand that efficiency is everything to make sure you get every ounce of electricity when conditions are overcast. In addition, you should seriously consider upsizing your solar array by 2 or 3 times if you expect regular cloud cover.

Unfortunately, nothing will match up to the energy supplied by direct sunlight but you can still see decent results in ‘less sunny’ areas. For example, you don’t only find solar panels in the desert or states like Texas or California. There’s many ‘cloudy’ areas of the world that enjoy the amazing benefits of solar power.