Solar Panel Phone Chargers: How They Work Best

We’ve all experienced it — just when you really need it, your smartphone dies without a charger or electric output in sight! Or, you’re out on a hike or camping trip snapping photos, when your phone battery dies and there’s no means to charge it.

One very simple, yet convenient solution to this problem is a solar phone charging unit. These devices harness the power of the sun to charge your phone when there is no external electricity source to plug into.

But do solar phone really chargers work? Are they even worth using?

Yes! Solar technology has improved dramatically over the last decade, and there are some fantastic solar panel chargers on the market.

In this article, we’ll be covering the following:

  • How solar phone chargers work
  • The benefits and drawbacks of solar phone chargers
  • Built-in battery solar chargers vs solar panel only phone chargers
  • Some of the best solar phone chargers available

If you spend a lot of time off-grid or are simply looking for backup power for your smartphone, read on below to find out more about these handy, convenient, and surprisingly capable devices!

Solar Panel Charging a Phone by the Pool
Solar Panel Charging a Phone by the Pool

Do solar panel phone chargers work?

While it’s true that solar chargers will most certainly get the job done and charge your phone when you need it, there are some drawbacks to these units too.

Firstly, they are powered by the sun and thus will only work in full, strong sunlight. Second, they are far lower in power output than standard electrical outlets and so depending on your phone, will typically take far longer to charge your mobile.

It’s also worth noting that some solar chargers work better than others, and when it comes to these little devices, you certainly get what you pay for.

Some solar phone chargers will charge a battery which then, in turn, charges your phone — even at night — while others charge your phone only directly from the panel.

As you’d expect, solar chargers with built-in battery units will cost a fair bit more but are certainly more reliable.

Is it good to use solar to charge phones?

You may be wondering whether it’s a good idea to use a solar charger for your phone, or whether there may be possible damage caused by using these units.

After all, mobile phones these days aren’t cheap and their batteries are already not very long-lasting as it is, so the last thing you want is to reduce their capacity further.

Again, the quality of the unit you use is paramount. Cheap solar chargers may not have well-controlled outputs, which can certainly damage your phone’s battery.

This means that the charging voltage will dip or peak depending on the sun, which can quickly damage your phone’s battery.

Solar panels on phone chargers are small — meaning they can only catch so much of the sun, and thus their output is also small.

A solar phone charger equipped with a battery pack can store power to use later, and thus kick out a higher wattage to charge your phone, quickly, and safely.

How do solar panel phone chargers work?

Solar panel phone chargers work by utilizing small solar panels to harness the power of the sun to charge either your phone’s battery directly, or a separate battery bank attached to the panel.

Most solar chargers can just charge more than just your phone — anything with a USB connection is usually fair game, although devices like laptops are too power-hungry.

In simple terms, a solar panel charger works the same way as any solar system, albeit on a far smaller scale, and so is only really suitable for mobile phones, Bluetooth speakers, or tablets.

Most solar chargers have a built-in Printed Circuit Board (PCB) which helps control the output current, indicate battery levels (if there’s a built-in battery), and charging status.

Some of these also have an additional micro USB, meaning you can charge the battery from a standard wall outlet or the sun, which is a useful addition.

Most of these units also have a voltage converter, boosting the output voltage to 5v— the standard charging current for most phones and tablets.

Do phone chargers use a lot of electricity?

The reason that solar panel phone chargers are possible, and that they work so well, is that phone chargers have such minimal electrical needs.

Most phone chargers use 2–6 watts of power while charging, and around 0.1 of a watt when left plugged in with no phone, and so do not use a significant amount of power overall.

For example, a new iPhone charger uses 5-watts to charge (although a generic charger can use up to 10 times more power) but even then, the amount of power consumed is minimal.

Phone chargers, even fast-chargers, use very minimal power, and so a solar panel charger is perfectly capable of charging a phone with ease.

Can a small solar panel charge a phone?

A solar panel cannot simply be plugged into your phone, no matter how small it is. The lack of voltage regulation will quickly damage your phone’s battery, as it’s not designed to handle such fluctuations in voltage.

As mentioned earlier, you need 5v to charge your phone, and any more can damage your battery.

That said, a 12v “cigarette” adaptor can be used to charge directly from a small panel, although it’s not very consistent and can potentially damage your phone.

A far safer, easier method is using a small panel attached to a battery bank and then charging your phone via the regulated current coming from the battery bank.

Of course, using a small, standard solar panel connected to a regulator and small battery, with a USB output or an inverter, would also work, but is certainly not as portable as a purpose-made solar phone charger.

How many watts does it take to charge a phone?

Most smartphones use between 2 and 6 watts while charging, with an overall average of 3 watts depending on the phone model.

This drops down to around 2-watts once your phone is charged, and 0.1-watts when nothing is plugged into the charger. The standard is typically around 0.5 Amps at 5v, which is around 2.5-watts.

An average iPhone can hold roughly 1,400mAh of power or around 5-watt hours. This means you could charge an iPhone from flat in two hours or less, using only 5 watts per charge.

How many watts is a fast charger?

Most smartphone companies offer “fast-charging” these days, which steps up the charging wattage to around 18-watts (iPhone), or around 12-watts as the standard.

These chargers can charge your phone up to four times faster than standard chargers.

For example, the above-mentioned iPhone could be fully charged — or close to it — in under an hour.

That being said, all phone manufacturers use slight variations of fast-charging technology.

To make these chargers charge your phone faster, most manufacturers either boost the amperage or vary the voltage — the latter being the most common method.

Fast chargers can bump up the amperage from the standard 1A charger up to 3A, or the voltage from 5v up to 12v and beyond.

Can a solar panel affect mobile phone reception?

Since solar panels do not produce electromagnetic radiation, they will not affect your phone’s reception.

That being said, an inverter does produce some electromagnetic radiation and may cause possible interference, especially if it’s not properly shielded, and so this can affect your reception.

The only way a solar panel could interfere with your cellular reception is if it’s physically obstructing the signal between your phone and a cell tower, but with the tiny size of solar panel phone chargers, this is highly unlikely, if not impossible.

How to use a solar panel phone charger?

Solar panel chargers are super simple to use, especially models with built-in lithium-ion battery packs.

These units typically have a USB output that you can simply plug your phone’s charger directly into.

The unit, naturally, needs to be placed into the direct sun to be charged before you can charge your phone, and the capacity of the battery will dictate how many charges you can get from it.

As mentioned earlier, some of these units can be plugged into a standard wall outlet to charge the internal battery too, which is certainly helpful.

Either way, charging your phone with a purpose-made solar unit is as easy as plugging in your cable to the USB output, and the unit’s PCB board does the rest for you.

How do you charge your phone with a solar panel?

There are typically three options charge your phone from a solar panel:

  • Using a purpose-built solar phone charger
  • Charging directly from the panel
  • Charging through an inverter

The easiest and most efficient way is to use an inverter, as this will give you the same charging current as a standard wall plug. Of course, these setups are expensive and not very portable.

The most portable method is using a purpose-built solar phone charger with or without a built-in battery bank, allowing you to charge your phone when there is no power outlet around.

The third, least consistent method is to charge your phone directly from a small solar panel using a 12v connector. This is subject to change in sun intensity, though, and so charge rates will fluctuate dramatically.

How to charge a phone directly from a solar panel?

Charging directly from a panel, without a battery bank, is a bit trickier and a whole lot less safe for your phone.

You’ll need a 12v cigarette lighter adaptor with a USB output, which you can then plug any charger into.

Of course, any fluctuation in weather conditions will dramatically affect your charge rate, and even a passing cloud may halt charging altogether.

Unfortunately, some phone chargers are not compatible with these 12v chargers as they do not deliver enough power, such as newer iPhone models.

Also, some phones will require a reset if the charging current stops, even after the current resumes, so you’ll need to disconnect your phone and reconnect again.

If there are a lot of clouds around, this can become tedious, to say the least.

If you are using a purpose-built solar phone charger, though, you simply place it in the sun, plug in your phone, and let the sun’s photons do the rest!

A military-grade solar phone charger

While the term “military-grade” sounds like something the US Marines would use, it simply refers to a unit’s toughness and how well it is made.

Military-grade solar phone chargers are typically shock-proof, water-proof, and sealed off from dust and dirt. In short, they are made to function under the harshest and extreme conditions.

These chargers are made not only to withstand dust, dirt, water, and shocks, but they can usually hold a high amount of power storage too.

Military-grade solar chargers are, of course, a lot more expensive, and if you are not taking your charger into tough conditions, it may not make sense to spend the extra money.

What is the best solar panel phone charger?

The best type of solar panel phone charger needs to be portable, durable, and ideally have a built-in battery bank. Without a battery bank, the energy from the sun is simply not constant enough to be reliable, but they are still useful.

There are a ton of great solar panel phone chargers on the market, some of them capable of charging a phone many times over and with varying features. Choosing the best one depends on what your needs are, though.

Do you need a rugged solar charger for hiking and camping trips? Are you looking for a portable, convenient battery pack for charging on the go?

Or do you simply want a solar charger for home use when the power is out? Solar chargers have a variety of features that will make one more suitable to your needs than another.

With all that said, our favorite solar panel phone charger is the Goal Zero Nomad 7 Plus. While the unit does not have a built-in battery bank, it is rugged, weather-proof, and uses some of the highest-efficiency solar cells on the market.

If you’re looking for a solar phone charger with a built-in battery bank, the BioLite 5+ is our favorite. It features a 2,200mAh integrated battery, which can be charged with the panel or via mains with the MicroUSB input.

Solar Phone Chargers

Solar panel phone chargers are certainly useful devices, and whether you’re an avid hiker or just want some backup juice to charge your smartphone, these units are certainly worth their cost.

Some solar phone chargers are only usable with direct sun, while others have a built-in battery pack to give you a boost when the sun’s down, and it’s up to you to decide which is best suited to your needs.

Depending on your individual needs, there are a variety of solar chargers to choose from, and when you’re caught with a flat phone battery and no electrical output insight, solar panel phone chargers can certainly be extremely useful.

If you’re out in the middle of nowhere, they can even be potentially lifesaving!

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