How to Make a Solar USB Phone Charger

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Solar power is no longer just for homes and campers. Nowadays portable solar chargers make it easy to recharge mobile devices on the go. No electricity? No problem, just get out in the sun, plug in your phone and watch the battery level go up. But what if you wanted to make a solar USB phone charger?

The idea of creating your own solar phone charger sounds intimidating, but the basic steps are really simple. Once you have created a DIY phone charger, you can use this to charge other devices like tablets. the basic steps are:

  1. Strip a USB cable to expose the black (negative) and red (positive) wires.
  2. Solder the diode’s negative side to the red wire.
  3. Cover the diode with heat shrink wrap.
  4. Add more heat shrink wrap on the wires.
  5. After soldering the wiring to the panel, apply shrink wrap.

There are 3 types of solar mobile chargers you can make. Let’s take a closer look at all three and how straightforward the process is.

Method 1: Make a Pure Solar USB Charger

This charger works with most GPS units, mobile phones and tablets.

Required Materials

  • USB charging cable
  • Soldering iron
  • Portable solar panel (preferably wired)
  • 1/4 inch heat shrink tubing
  • Wire stripper
  • 1N914 blocking diode


  1. Use the wire cutter to snip the ends of the USB cables. Remove the insulation so the white or black (negative) and red (positive) are visible.
  2. Get your solar panels. Solder the black part of the diode (the negative side) onto the red wire. It should not face the solar panel. This is necessary to keep the solar cells from using up power. Solder some more to the diode’s opposing end. A few inches will be sufficient.
  3. Although not mandatory, it is a good idea to solder in a voltage regulator (5 watts) onto the unit. Modern mobile phones can handle 6V, but it you have an older model the regulator is necessary.
  4. Use the heat shrink wrap to set the diode onto the wiring. Apply more heat shrink onto the USB wires.
  5. Lastly, solder the wiring onto the solar panels. If necessary, use heat to shrink the wrap.

While this solar charger works fine with most mobile devices, you might encounter trouble with iPhones as they demand consistent 5V to turn on the battery charge. For an iPhone, a solar battery USB charger is a better option.

Method 2: Make a Solar Battery USB Charger

Solar battery USB chargers are compatible with iPhones, tablets, mobile phones, lithium ion batteries and GPS devices. The difference between this charger and the one earlier is you wil be using a battery.

Required Materials

  • A portable solar panel
  • Battery holder (AAA or AA)
  • 1N914 blocking diode
  • 1/8 inch wire
  • 1/4 in. heat shrink tubing
  • Case for charger storage
  • USB charging circuit
  • Super glue
  • Wire stripper
  • Soldering iron


  1. Solder the negative side (black) of the diode onto to the solar panel’s red wiring. It should be facing away from the solar panel.
  2. Put heat shrink tubing on.
  3. Solder some fresh wiring onto the diode’s positive side. Not a lot, just a few inches is fine.
  4. Twist the battery holder’s negative wire (black) onto the solar panel’s black wiring. You should end up with parallel wires. The battery holder wiring and the panel should also have a connection newly opened. Repeat these steps for the red wire.
  5. Get a USB charging circuit and find the + and – signs. Get the solar battery / panel wiring you just made and solder them onto the circuit’s + and – points. Do this slowly.
  6. Glue everything inside a case. Sturdy tape will also do.
  7. You’re done. All that’s left is to test the charger. Get some charged batteries, set them in the charger case and plug in your smartphone. If the charger isn’t working, there might be a problem with the soldering points. If it is charging, get some dead batteries and watch the charger restore them.

Tip: install a second solar panel and place a diode between the two. This will allow you to charge larger, more powerful devices and much faster too. By hooking up the black and red cables between the battery case and the panel, you’ll get a nice charging light.

Method 3: Make a Lithium Solar Battery Charger

As you might have guessed, this is for recharging lithium ion batteries. Most mobile phones today use lithium battery, a testament to its quality and dependability.

Required Materials

  • Super glue
  • Wire stripper
  • Soldering iron
  • Storage case for the charger
  • Battery holder (AAA or AA)
  • 1N914 blocking diode
  • Portable solar panel


  1. Just like the previous method, start by soldering the diode’s negative side (black) onto the solar panel’s red wire (positive).
  2. Apply the heat shrink on the battery holder wires.
  3. Solder the battery’s negative wire on the solar panel black wire. For the red wire, Solder it onto the diode.
  4. Put the system in a case or small tin box. Glue or tape everything.
  5. Test the charger.

Pure Solar Battery Charger vs. Battery Solar Charger

Direct or pure solar USB chargers are very light and easy to make. Just strip a USB cable, stick to a solar panel and it’s good to go. The solar panel does the work of converting the sun’s energy.

The drawback is direct USB solar chargers do not generate a lot of power. They are also insufficient for devices that need a lot of amp power. Lastly, direct solar chargers depend entirely on the sun. If it’s cloudy or the sun’s intensity wanes off, so does the energy flow.

Battery based USB solar changers are not as portable, but they’re more practical. You can charge the panel during the day and at night plug in your phone.

Frequently Asked Questions

How Long Does it Take for a Solar Charger to Charge a Phone?

A few hours at least. Battery based USB chargers are faster, but even then expect to wait hours to get a full charge. it also depends on how much you used up your phone. The weather condition also plays a factor.

An iPhone comes with 3.7 volt battery (100 mA). With a 6.5 watt solar array (433 mA/hour) it will take 3 1/2 hours to charge the iPhone (0 battery to 100%). This assumes that the sun is at its peak for the entire 3 1/2 hours, however.

You can make things easier by not waiting for your phone to drop to 0% before charging. It also helps if you keep your solar charger charged up during the day so you can power up your phone at night. More powerful solar chargers are becoming available with shorter charge times though. You can also try these tips to make phone charging faster.

How Can I Charge My Solar Battery without the Sun?

Artificial light sources like LED will charge the battery. However it is going to be a lot slower and isn’t practical. You are better off with the sun.

Do Solar Chargers Need Direct Sunlight?

Direct sunlight is not needed for solar chargers to work, but you will get the best results if the charger is directly exposed to the sun. In some cases it may not be possible to place the charger directly under sunlight, but as much as possible try to.

Will Solar Charge on Cloudy Days?

The charger will still charge, but it will be at a lower level and take longer. That’s why it is best to charge during daytime so you get the best results and faster too.

Why Isn’t My Solar Charger Working?

The most common reasons are:

  • Check the wire soldering for damage.
  • The solar panels are dirty.
  • The phone is damaged.
  • There is no sun.

Do Solar Phone Chargers Really Work?

Assuming you followed the instructions above, yes, they do work. As pointed out, an iPhone is better suited for a battery based solar charger than the direct type. but for Android and other types of phones, any of the methods above will do.

What Solar Panels Do I Choose?

Any type of portable solar panel will do. Just make sure it has the power needed to charge your phone (and whatever other device you want to charge). Even the cheap ones will do as long as they’re not damaged.


Learning how to create a solar phone charger DIY style is not that difficult as we have shown. The fact that the costs have gone down, and keep going down is another plus. Sure you can buy a charger easy, but knowing how to make one means you can customize the features to suit your specific needs.