How much Solar Power do I need to Charge a Phone?

How much Solar Power do I need to Charge a Phone? Quick Guide

4 Min Read

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With all the distractions around us, sometimes we need a break from our daily lives and head out into nature. It doesn’t matter if you’re hiking or camping under the stars; getting away will do wonders for your mental state.

What happens when you’re miles from civilization and your cell phone goes dead? You can’t call for help if you don’t have a way to charge your device! That’s where solar power comes in handy.

But how much solar power do I need to charge a phone?

In this blog post we’ll go over everything you need to know about harnessing energy from the sun so your phone never runs out of juice.

How much Solar Power do I need to Charge a Phone?

A smartphone uses 2 to 3 watts from its battery when in use. The battery holds a charge of 1,440 mAh, or about 5.45 watt hours. A solar panel will need to provide a minimum of 5 watts when charging. Ideally 10 to 15 watts of charging power is recommended.

A lower wattage means that you will need more time to charge your phone.

In order to fully charge the phone battery, the solar panel charger voltage must at least match the voltage of a fully charged phone battery. A fully charged phone battery is 4.15 V (540 watts).

As an example, let’s compare the voltage in a phone battery to the air pressure in a bike tire. If you want to fill the tire to 20 psi then you must have an air source that is at least 20 psi to move the air into the tire. It’s the same concept as applying voltage to charge a phone battery.

Types of Solar Chargers

There are two types of solar phone chargers; direct and battery bank.

Direct solar chargers send power directly from the sun’s rays to your device.

A battery bank solar charger collects energy in an external battery pack that can be charged by either sunlight or plugging into a wall outlet when needed.

How does a Solar Charger Work?

The solar panel converts sunlight into usable charging power for your phone. The speed at which this happens depends on the efficiency of how much light is received by nature. By using sunlight to make the electrons in solar cells flow in a circuit, this creates current and thus charges your phone battery.

The amount of solar exposure however is affected by many factors such as weather patterns. Portable solar photovoltaic systems require direct sunlight on every single cell before they can produce electricity.

So it’s important to keep this in mind when out in nature and needing to charge your phone.

How long does a Solar Charger take to Charge a Phone?

The time it takes for a solar device to charge your phone will depend on many factors.

Portable solar panels are designed to be small. The batteries that they are charging generally have a very large capacity. So charging them completely takes a significant amount of power.

As an estimate, a fully charged portable solar panel will recharge a phone with 5% battery life to full battery life in about two to three hours.

It’s nearly impossible to calculate exactly how long it will take for a solar-powered device to charge a phone. That is because of the environmental factors.

Keep in mind a portable solar charger is not designed with the idea of charging from zero. Instead they are designed to be a maintenance of charge. Maintenance charges always take much less time and energy.

Is Charging Phone with Solar Bad?

No, charging your phone with a solar charger will not damage your device. The two most important factors to be aware of are the voltage of the solar panel output and of the phone battery you’re connecting to.

When you use a solar charger to recharge your phone, it’s important that the device be used minimally. Try not to use any apps or checking social media for awhile when charging with one of these devices in order maximize its efficiency.

With that said, here are my four favorite solar phone chargers:


So, if you’ve been looking for a way to ensure that your phone never runs out of juice again when you find yourself in the middle of nowhere, a solar charger might just be the answer for you.

Hopefully this blog post has helped answer how much solar power do I need to charge a phone.



Brian has spent over 30 years as a general contractor, and in that time seen and faced many challenges. He brings all his knowledge of portable generators, battery powered tools, and outdoor equipment to every post he writes through real life experience. Learn more about us.

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