Can I use a 5V solar panel to charge a battery? | Solar panel wholesaler

Can I use a 5V solar panel to charge a battery?

Can I use a 5V solar panel to charge a battery?
Can I use a 5V solar panel to charge a battery?

The short answer is; Yes you can.

The long answer is that you have to create a solar penal charger first if you want to charge your phone. You can follow the below-mentioned steps to create a solar charger. First thing first, you need the following items before jumping to steps.

  • 2 3W 9V solar panels
  • 22 gauge stranded wire
  • 5V DC/DC buck converter
  • Wire strippers
  • Soldering iron
  • Safety glasses
  • Multimeter

Step 1: Wire the Solar Panels in Parallel

Cut a length of wire to connect the panels’ positive terminals. Give yourself some slack in the wire so it isn’t pulled taut when the panels are folded.

Note: Because my panels have two pairs of terminals on the back, before wiring I used a multimeter to check their voltages. It turned out the terminals that output 9 volts are the two “top” terminals — not the terminals with the “+” and “-” signs. Strange.

Strip and solder the wire from positive terminal to positive terminal. (I decided to orient my panels in opposite directions to lessen the stress on the wire when the panels are folded.)

Tip: Keep your solder joints as flush as possible with your solar panels. This helps later on when gluing them to the fabric.

Cut a length of wire to connect the panels’ negative terminals. Once again, give yourself some slack.

Strip and solder the wire from the negative terminal to the negative terminal.

Step 2: Solder the Leads to the Panels

Cut a length of wire for the panels’ positive lead. It will connect one of the panels’ positive terminals to the buck converter’s positive terminal. Make sure it can reach where you want to place the converter. Don’t forget some slack!

Strip and solder the positive lead to one of the panels’ positive terminals.

Cut a length of wire for the panels’ negative lead.

Strip and solder the negative lead to one of the panels’ negative terminals

Now let’s test the panels’ voltage and amperage outputs with a multimeter to make sure we wired everything correctly! Connect the meter’s positive probe to the positive lead and its negative probe to the negative lead.

What outputs should we expect?

Well, here are the specs for the panels I used:

  • 3W
  • 9V
  • 333mA

Wiring solar panels in parallel adds the current (amps) together while keeping the voltage (volts) the same.

Thus, for volts, you should see a number around 9V DC.

Almost 10V DC. Perfect!

For amps, you should see a number around 666mA (333mA * 2). But in real-world conditions, expect solar panels to output a little less than their stated current.

Tip: You’ll likely have to switch the red probe to your multimeter’s other port in order to measure this amount of current.

557mA. Check!

Step 3: Solder the Buck Converter to the Leads

Locate the positive and negative terminals on the buck converter.

Solder the positive lead to the converter’s positive terminal and the negative lead to its negative terminal.

Now you should have a working solar charger!

Time to check that it’s working.

First, make sure the buck converter is connected properly and working by shining some light on the panels. Its LED should light up.

The LED is on. Looks like it’s working.

Next, test your charger by placing it outside in direct sunlight and plugging into your phone or USB device. Your device should start charging.

My Kindle’s charging light turns on when I plug it in — my charger is working!

I tested my charger’s output with a USB meter to confirm that the charger was indeed outputting a decent current at 5V.

It’s outputting 460mA (about half an amp) at 5V. That’s about 2.5W, or half the rate of a standard 5W phone charger. (During real-world use it regularly got up to 3W.)

According to our solar charging calculator, it will take about 10.8 hours of direct sunlight to fully charge my iPhone XR.

Definitely not the fastest solar charger, but it’ll top off my battery in a pinch.

Optional: Shrinkwrap the buck converter using heat shrink tubing and a heat gun. I did this to for aesthetics and to protect the circuit board a bit. It covers up the converter’s LED, but that wasn’t a big deal to me.

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