Better Than a Solar Generator (for small electronics)

Sometimes people write me to ask my opinion on solar generators. That is, which one should they purchase. My response is usually that I’m not a fan of solar generators and that they should consider other options. I say this for three primary reasons:

• Sometimes people don’t realize they actually need to purchase panels to go with the generator they choose (unless it’s a bundled item) which adds to the upfront cost.
• They’re not the most efficient option when it comes to money spent versus watts you receive in return.
• Solar generators offer a false sense of security because people seem to believe they can simply purchase one and they’re instantly good; maybe they assume it’s like the typical generators we’re familiar with–just pour sunlight into the gas tank and you’re back in business.

The first problem is relatively easy to fix. Just search for solar generators with panels included or, at least, factor in the cost of panels.

The second problem is the biggest concern to me. You see, I prefer DIY approaches because you can (1) get things setup the way you want and (2) save money. But I get that not everyone wants to spend the time or effort putting together a better, cheaper DIY setup. And, let me be clear, a useful DIY solar setup isn’t cheap either. I’ve spent thousands on mine and even then it’s not going to power everything I want it to.

So let’s think about what we really want to power. Most of us want to power a refrigerator or maybe a freezer. Most refrigerators that I’ve seen require between 100-400 watts during normal use and 400-1000 watts of power or more during startup or during their duty cycles. These numbers depend on several factors, with efficiency and size being the primary drivers. Mini refrigerators, thankfully, tend to draw less than 100 watts of power during normal operation, but there’s a catch–mini fridges tend to run more often. Chest freezers typically use less power than refrigerators, though size does affect power consumption, too.

To really know for sure, you need to investigate your appliances. Find the stickers that’s plastered somewhere on the inside and read the numbers. If necessary, look up your model online. As an example, our upstairs refrigerator (manufactured in 2010) may use up to 5.3 amps or 636 watts (5.3 amp x 120 volts) of power. Our newer refrigerator (manufactured in 2023) may use up to 3.0 amps or 360 watts (3.0 amps x 120 volts). Granted, the downstairs fridge is somewhat smaller in size, but not by much.

These are important numbers to know because, if you intend on purchasing a solar generator to run a refrigerator, as in this example, then you need to understand whether it can actually do so.

With that in mind, let’s look at some options. Let’s say we have a 250 watt, relatively small and/or efficient refrigerator. This same refrigerator may use up to five times that amount of power on startup–possibly over 1000 watts–and relatively higher power draw during its duty cycle (when it uses more power to run the compressor) which, from what I understand, is about a third of the time.

Can your solar generator even power the refrigerator?

When I type “solar generator” into Amazon, I get many results for solar generators (basically just larger power banks, often without panels) at around 300 watts for something between $150-200. That would be enough to keep the fridge going, but they often state that max power output is 600 watts. This, sadly, probably wouldn’t allow my larger refrigerator to even start. Ugh.

But let’s say I did get it started or used our smaller downstairs refrigerator. How long could it run? Well, because you must factor in efficiency, losses, and other problems, we can only assume you’ll get roughly 80% power output, which means you’ll get less than an hour of runtime. That’s not a lot. Let’s hope the sun is out all day…and half the night.

Using the same math as above, a 1000-watt solar generator could keep the same refrigerator going for 3.2 hours before needing recharged. That’s not bad assuming the sun is out and that the refrigerator likely won’t need to run the entire time. But it could need to run the entire time if the power has been out for several hours…or it’s hot indoors….or you keep opening the door. You get it.

This is why I much prefer to get a quality power inverter, something between 1500-2000, watts and connect it to a vehicle to power larger appliances. I could, for instance, run the vehicle for an hour to cool down the refrigerator and repeat the process as necessary. Unsurprisingly, this idea also works at night. Store enough gasoline and you’ll be good for days or weeks without worry.

Clearly, refrigerators aren’t the only concern. Some people may want to power a window air conditioner or their entire entertainment center. These items will need even more power, and that’s where traditional generators OR larger solar (or wind) systems come into play. That’s a topic for another day.

There are a whole host of other useful items that you may want to power besides large appliances. I mentioned a few of them in my post about building a DIY Faraday cage the other day. These items usually draw relatively little power, and include radios, rechargeable flashlights, and small fans. It might also include the ability to recharge batteries, tablets, and smartphones.

Whether I like it or not, I’m beginning to amass a number of electronics that need to be recharged (as opposed to using disposable batteries), which has me changing my plans for a lengthier grid-down scenario.

So, what have I come up with?

Make your own solar generator! It’s simple. Really.

Just purchase yourself a good, relatively large folding solar panel and you’re set (assuming it has the appropriate circuitry to charge devices at their required volts and amps; most seem to.) As an example, I purchased this 40-watt folding solar panel for $80 to use for this very purpose. You could probably get away with the 20-watt version for about half that price, but most devices will take longer to charge.

But not necessarily that much longer. For example, I also recently purchased this much smaller 6-watt panel and used it charge one of the rechargeable flashlights I like to use just the other day. It worked just fine. Then I tried my phone and it wasn’t so good. More power is more better for power-hungry devices.

That said, you can’t just plug any solar panel into any device without a problem. All small electronics expect certain voltages and amperages, so ensure whatever you’re purchasing won’t overdo the device’s maximum ratings. Again, research the numbers. And, like I said above, you’ll want to ensure that the folding solar panel has the circuitry to adjust volts and amps. From what I can tell, most of the “folding” versions do because people are expected to take them camping or hiking. But it can’t hurt to be sure.

Power banks to the rescue?

The third problem is something that everyone with a solar panel runs into: times when the sun isn’t shining, or it’s raining, or the solar panel fell over because you had it propped up without any bracing and the wind knocked it over. Or whatever.

This can be mitigated by purchasing one or more portable power banks with 20,000+ mAh ratings or even larger. I used to only dabble in power banks that are 10,000 mAh or less because they’re cheap and not very heavy, which means they’re great for bug out bags or even EDC. This time, however, I purchased three 26,000 mAh power banks as well as two 40,000 mAh power banks for this very purpose–to charge small electronics during a grid down scenario.

Even by purchasing a solar panel and a single power bank for about $100, I’ve effectively created my own solar generator for less money than what I could get online. And by adding more power banks I can increase capacity (depending on how much charge I can get out of the folding solar panel) and add redundancy. In fact, if I manage things right, I can keep the solar panels constantly producing power to either recharge devices (flashlights, phones) or a power bank for times when the sun isn’t shining.

But do these small power banks really compete with a solar generator?

I can say that there is probably two downsides: power banks won’t include an AC plug; however, converting DC to AC back to DC (solar -> inverter -> device) isn’t efficient, either. I won’t complain about that problem. The other big issue is that a 26,000 or 40,000 mAh power bank (let’s assume their numbers are accurate, though probably not) will take A LONG TIME (measured in days) to recharge via a solar panel.

Let’s do a bit more math. That same 300-watt solar generator at 5-volts (a common voltage for many small electronics) will generate 60,000 mAh at most. If we use the 80% rule, it’s more like 48,000 mAh. This is starting to get close to the larger power banks I mentioned above. Granted, these power banks aren’t going to be 100% efficient, either. So, let’s say we purchase two of the smaller 26,000 mAh power banks for $50 at the time of this writing. That get’s us fairly close to the power generated by most 300-watt solar generators. Add in the 40-watt panels and we’re at about $130.

Okay, so it’s not a huge savings over most generators in the 300-watt range, but it’s still a good deal and you can certainly go for lesser expensive options. If I went with the 20-watt panel for $40 and a single 26,000 mAh power bank for $25, then I’m at $65 total and still capable of charging most small electronics. Truth be told, I could just skip the power bank and be able to charge most devices, though there is that pesky problem of what to do when the sun isn’t shining. Hence, the power bank.

Now, what about mimicking the larger, 1000-watt solar generators?

That’s a bit tougher to do, if I’m being honest. An 1000-watt solar generator will easily cost $500 or more, not including the solar panels, which will cost you an additional few hundred dollars. For comparison purposes, 1000-watts of power at 5-volts translates into 200,000 mAh. Thus, we’d need to buy several of the aforementioned power banks at a cost of about $200 total.

And we’d need to up our solar panel game substantially. The problem is that you can’t just purchase a 100-watt or larger solar panel and get them to charge a power bank, all of which have some sort of USB connection as their power input. I’ve looked for options and it’s not obvious what to do. Again, the only solution might be to quadruple the number of solar panels to compensate. Doing so would cost $320 at the time of this writing. Total cost would be $520 for similar power generation.

But, I don’t see any real purpose in all of this unless you have so many small electronics to charge and use, such as for a very large family or all your neighbors, that you need to charge a dozen devices or more at a time. This might be overkill, though redundancy is a prepping tenet. Granted, there’s also something to be said for NOT having an AC plug to power larger draw appliances, a laptop, or other AC-powered necessities, such as a CPAP machine. But, again, this is about keeping small electronics going for long periods of time.

What do you think? Am I on to something or completely full of it? Is there a better option? I’d be happy to hear your thoughts.