Solar Panels: A Prepper’s Buyer Guide for Emergencies

June 13, 2021
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In this blog, we’re going to take a look at solar panels.  Solar panels offer an infinitely renewable energy source that can provide power to critical devices if the grid were to go down.  This channel primarily focuses on emergency preparedness and we’ll look at solar panel choices from this perspective: what are the best panels if there was a disaster and you had to generate your power?  I’ve tried to boil down the options to the basics to help give you the essential information you need without getting overly technical, so you can decide which of these is best for you.  

All solar panels essentially work the same.  They capture the sun’s light energy and then transform that energy in their cells to create DC–or direct current.  That current is typically then routed to charge a battery or solar generator, which can power many of your household plug-in devices.

When it comes to solar panels, you do get what you pay for.  The cost goes up with efficiency, wattage, portability, hardiness, and the versatility of deployment.  You want the highest wattage in the broadest range of sun exposure scenarios, and you want to have the right panels for your situation and budget.  Some panels won’t work if even one section of their cells is covered or completely shaded.  Others will still output after being filled with bullet holes.  If you are looking at the possibility of heading out during a disaster, some of these options will work better than others. 

In this blog, I want to lead off by looking at newer solar panel technology — foldable panels and solar blankets.  After that, we’ll jump into the considerations when shopping for solar panels, and I’ll do a brief run-through of typical solar panels with the benefits and detractors of each.

Foldable Solar Panels

When it comes to solar and mobility or deployment anywhere, a foldable, spreadable, solar blanket can’t be beaten.  All that efficiency and versatility come with a heftier price tag though.  These are made for durability and portability, so it’s the best option if you are on the move—the lightest option and with the best power output to weight ratio.  The real bonus to the flexible solar version is that it will perform better in low light or partial shading.  They are wired in series, so if one of the sections of cells is covered, it will still collect energy.  These Off-Grid Trek solar blankets use Sunpower Gen 2 Solar cells with a 23.5% efficiency rating that also work extremely well in low light conditions.  A significant advantage to these is you can spread it over non-flat surfaces.  If a sharp rock dropped onto a section of the panels, the whole panel isn’t ruined.  So, they are super hardy. 

These 120W Powerfilm and 120W Solar Blanket, both, are under 8 pounds.  That is amazing when you consider that a 200-Watt monocrystalline panel that will produce roughly the same output in watts weighs in at around 25 pounds, over three times the weight.  Obviously, the ability to fold a solar blanket up and put it in your pack and go is a massive advantage to maintaining mobility after a disaster.  Your typical rigid 200-Watt monocrystalline or polycrystalline panels can be over five feet long and two feet wide.  That makes them difficult to bug out with when time is of the essence.  

The Solar Blanket and PowerFilm will work better in low-light situations compared to monocrystalline or polycrystalline solar panels, something we’ll cover momentarily.  The Solar Blanket is one-fourth of the size of the Power Film blanket.  It’s completely waterproof versus water-resistant, and it produces more electricity than the large Power Film and at a lower price point.  These are your best options for overcast days as they will still work when a rigid panel cell will not.

Both the PowerFilm and the OffGrid Trek Solar Blanket are solid choices.  They’re both lightweight, easily portable, and easily deployable in most terrain and situations.  These are built with rugged military usage in mind.  They’ll both sustain damage and keep working, though they’ll drop in their efficiency.  The Off-Grid Trek Solar Blanket represents the next generation for these products.  Compared to the PowerFilm, it has a smaller footprint, is waterproof versus water-resistant, and is about 2/3rd the price.  I’ll be doing a more in-depth video on Off-Grid Trek’s products in the coming months as their products check a lot of boxes for me when it comes to prepping: lightweight for mobility, durable, and efficient.  I’ll post a link in the description section below along with a coupon code if you want to check out their products.

Basics of Solar Panels

Monocrystalline vs. Polycrystalline

You’ll hear these terms a lot when it comes to rigid solar panels.  Monocrystalline solar panels have solar cells made from a single crystal of silicon, whereas polycrystalline solar panels have solar cells made from many silicon fragments melted together.  Polycrystalline solar panels, also referred to as “multi-crystalline,” or many-crystal silicon, generally have lower efficiencies than monocrystalline options, but their advantage is a lower price point.  Both are good choices for your home and other fixed permanent or semi-permanent locations.  This is going to be your most affordable option without sacrificing too much on output.  You can’t take these on a hike, but it’s going to be ideal to mount to a vehicle, RV, or structure.  In low light, you will see more significant decreases in output.  In partial shade, their performance suffers greatly.  While a parallel connection is possible these panels are most commonly designed to be wired in series, so if one of the cell sections is completely covered, the entire panel will cease to output energy.

Wattage

Solar panel wattage represents a solar panel’s theoretical power production under ideal sunlight and temperature conditions. Wattage is calculated by multiplying volts times amps where volts represent the amount of force of the electricity and amperes–amps–refers to the aggregate amount of energy used.  Even a 20-watt panel will charge a battery, but it will take significantly longer, maybe days, to charge a large battery.  A 20-watt solar panel might be suitable for charging small electronics and 12-volt batteries.  The basic math here is the panel’s wattage times the number of hours of sunlight times the number of panels.  That’s going to give you the total watts.  One thousand watts is 1 kilowatt.  The more wattage the panel produces, obviously, the more electricity you have to work with and the shorter amount of sunlight needed.  

For this reason, the higher the wattage of the panel, the greater the cost.  For wattage, you need to circle back to the question considering your energy needs.  Are you going to need to power a refrigerator or just charge up small devices?  Are you going to need power tools or simply provide light through the night?  The wattage, size of the system, and solar panels required all hinge upon these questions.

Efficiency

A 6-12% efficiency rating means that 6 to 12 percent of the sunlight that falls on it gets converted to energy.  20% efficiency means that 20% of the sunlight is captured and converted to electricity.  The average solar panel efficiency is between 10 to 12%.  The solar panel market is not regulated so solar companies advertise like auto manufacturers stating you will get up to a certain MPG that you never see unless you are driving downhill with a strong gust of wind at your back.  So when you see the “up to” symbol or between a certain range you know it is not actually a true efficiency rating.  Also, be aware that all solar panels will degrade in performance for every degree over 77 degrees Fahrenheit, 25 degrees Centigrade.  

Scalability

One panel that produces 100 watts connected to four similar panels will provide you an array producing 500 watts.  The ability to connect multiple panels into your system will give you more electricity to work with.  So with any component or panel, you want to make sure that you can scale it up, and you want to be aware of any limitations.  Some systems might be completely closed.  Some might allow you to connect up to a limited number of additional panels, but that’s it.

Deployment

The next consideration is how you expect to deploy the panels.  If you’re going to affix it atop a structure permanently, your rigid panels will give you the best performance and are the most resistant to annual weather.  They’ll hold up better.  If you expect to be mobile but have limited pack room, a foldable panel will allow you to pick it up and transport it in and out of a vehicle much more easily than non-foldable panels.  Plus these foldable panels have legs you can adjust to ensure you’re getting the best angle for maximum sun exposure.  At the ultimate end of deployability is the foldable or solar blankets.  These have a minimal footprint in your backpack and the options on the market can go up to 215 watts.  They will work even if several cell sections are damaged or covered.  The PowerFilm option is water-resistant and the Off-Grid Trek solar blanket is waterproof.  You can quite literally fold them up, go, and then redeploy them in a matter of seconds in almost any terrain.  All that versatility and efficiency do come at a price. They’ll be the most expensive of the bunch, as well.

Light

Will you be able to get direct, unobstructed sunlight, or do you live in an area where overcast days are the norm?  If sunlight is a rarity in your area, you will want to get panels wired in series which increase voltage and operate best in low-light conditions.  Panels connected in parallel increase amps which work best in bright light conditions.  Your out-of-the-box rigid, aluminum-framed panel will not perform at peak on cloudy days, but with the help of some parallel branch adapters, you can be up and running.  In a series-connected array, even the passing shade of a tree as the sun transits the sky can zero out your energy production by dropping the efficiency too low to be of consequence.

Storage

Finally, you need to consider what you will do with all that free energy you’re pulling out of the sky.  If you don’t have a battery or solar generator system, all your energy needs to be used in real-time, or it’s simply wasted.  I have done several reviews on solar generators, so I’ll let you take a look at those videos to find out more.  I’ll post a link to the playlist in the description section below.  These solar generator systems typically range from a few hundred to thousands of dollars.  This, too, is going to depend on what you think your energy needs will be.  Their prices will vary by multiple factors including their allowed input, kilowatt-hour storage, continuous output, and weight as well.  Many people find it easier and more affordable to buy a whole kit that fits their needs, which is a good strategy for beginners. 

Rigid Solar Panel Considerations

Here’s a quick rundown of the rigid solar panels I’ve collected for us to look at here today.  I don’t want to delve too deep into the science, but I do want to highlight the practical aspects for emergency preparedness of each covering what you should look for when shopping these options.

The Solar Storm Rigid Polycrystalline 100-Watt Solar Panel is a good choice for getting the most power per dollar. It is a rigid panel and is very affordable at a price point of just over 100 dollars. The polycrystalline PV cells are encased in tempered glass and framed in aluminum.  It has limited portability for mobile applications but it would be your best choice for permanent exterior mounting.  I’ve used these panels in the past where I won’t move them much and know they can handle the elements.

The Ascent 100-Watt Solar Panel is a happy compromise between the rigid and flexible solar panels because it folds in half like a suitcase.  That makes it much more portable than the other two and less susceptible to damage.  It’s an excellent mobile choice, but not as suitable for permanently fixed use. This panel includes a rugged kickstand that allows you to adjust the angle to optimize charging.

I’ve also received other solar panels over the years reviewing these and a few worth mentioning are the Jackery and EcoFlow solar panel options.

The Jackery SolarSaga 100W Solar Panel takes portability seriously and has an even more rugged design.  It also weighs just 9 pounds, so it is lightweight, foldable, and with an easy-carry handle.  It has a built-in kickstand to help you adjust the angle for maximum sun exposure.  While this panel is fine for charging smaller devices, its connection type definitely limits its capabilities. 

The EcoFlow 110W Solar Panel is built to be scalable and portable.  You can chain several panels together to generate power more efficiently.  It’s foldable and waterproof.  You simply need to unzip it, unfold it, angle it towards the sun, and plug it into the battery system.  The built-in kickstand allows you to angle it from 0 to 180 degrees. 

Conclusion

I live in the southwest of the United States in sunny Southern California, so all these panels will work for me on any of the many sunny days here.  Rigid solar panels all share one major drawback over solar blankets: they all require very direct sunlight.  That’s not always possible.  If you are frequently in overcast situations, though, these solar panels either won’t work at all or will barely work.  Here is where the foldable sort of solar blanket instantly increases your options.  The PowerFilm and the Off-Grid Trek will both work on cloudy days.  Their energy production will drop, of course, but paying a little more to have the security of reliable power may be worth it to many in the long term.  I’ll do a future blog going into more technical details about series versus parallel, voltage, amps, and low lighting conditions.  This blog is meant to be more of an introduction or primer blog if you’re currently shopping solar panel options for emergency preparedness.

Hopefully, understanding the fundamentals of solar panels and systems and understanding your true post-disaster or off-road and camping power needs will be enough to let you determine a solar system that is right for you.  While I think the ultimate from a survival perspective is the foldable blanket type, specifically the OffGrid Trek solar blankets, they do come at a cost.  Assess your needs and go from there.  Having a solar solution or two in your prepping inventory is a game-changer.

What do you think?  What’s your power solution? 

As always, please stay safe out there.

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