Pure Solar USB Charger

This DIY is super easy and fast (bonus: it's also environmentally friendly!)

Things you'll need:

• Solar panel (I used a 3V / 250mA one)
• An Eclipse mint tin (or whatever you like)
• Some wires
• Drill
• 2.5mm male jack
• 2.5mm female plug
• DC to DC Boosting Circuit with USB
• 1N4148 Diode
• Electrical tape
• Hot-glue
• Soldering iron
• Solder

If your solar panel is more than 5V then you need a step-down circuit. If not, a step-up one (to 5V) is fine.

Step 1: The Solar Panel

I’m using the same solar panel from my Solar USB Charger project, so it’s already wired with a 2.5mm male jack. You can wire the panel directly to the circuit, but I prefer having a DC connector because I can use it to charge my phone, my phone charger AND my rechargeable batteries.

If you have not done so:

Solder the positive wire to the longer leg of the 2.5mm male jack and the negative wire on the other.

Step 2: More Soldering

Place the plug with the empty side facing down. The left tab is negative and the middle one is positive.

Solder the negative side of the circuit to the left tab, and the 1N4148 diode to the middle tab. Remember that the black side of the diode should be facing away from the tab. Hook it up to the positive side of the circuit with a wire.

Step 3: Drilling

Drill a hole at the bottom of the tin.

Step 4: Insulating

Insulate the tin with some electrical tape

Step 5: Hot-gluing

Hot-glue the soldered parts to the tin. There’s already an opening in the front so I don’t need to drill a hole for the USB port.

Step 6: Done!

Comments

[Ken wei]

you could use an altoids tin for the case

[ShioriToshiko]

That's what I did.

[NeroliKo]

Yes but I don't have one

[dougstrickland]

Its times like this that I wish Instructables had a comment Like button. So many people forget that at the heart of hacking and making is beginning with the things you have on hand...

[Ken wei]

I use 2 1.2v 3000 mah rechargeable batteries and solder it to the solar panel. Then I solder the solar panel and the batteries to the charging circuit.It works as well.

[kingc4]

Hi i'm a newbie to electronics. i'm thinking about making this project as a Christmas gift for some relatives. would it be possible to skip the 2.5 mm jacks and solder directly to the dc to dc boster?

[NeroliKo]

Yes it's theoretically possible to skip the 2.5mm jack. However, you'd have to find a container that is big enough to fit the solar panel.

[kingc4]

Thanks for the response. By the way great tutorial! I am thinking about using a Altoids container with a solar panel mounted on the outside. Also based on your response to raihanpl the way i understand it to charge a phone you need to match the ma and voltage. based on my research (a quick google search) i found that to charge a iPhone you need 1000 Ma 5v. this means i need a 1000 Ma 5v solar panel is that correct?

Btw i'm still fairly new to building electronics so excuse my newbieness

[NeroliKo]

The reason why you need a boosting circuit is because you need to boost the output voltage from, let say, 3V to 5V. Therefore, you don't need to have a 5V solar panel. The same apply to the current.

And don't worry about being a newbie. I've only started making things 3 months ago so I'm still a beginner.

[raihanpl]

it can charge tablet or other big device ? and your boost is 600 MA?

[NeroliKo]

From my memory the usb booster I use outputs a 600mA current so it can't even charge my iPhone. Naturally, charging tablet or bigger devices should be impossible. However, if you're able to find a boosting circuit that outputs the current needed for your device, it's theoretically possible to charge it. Just note that you might need a more powerful solar panel.

[eliasrm87]

¡Very good tutorial! But, I suggest to use a schottky diode for better efficiency. This diode type can be found on some old
PC power supply...

[NeroliKo]

Thank you for the recommendation!

[DeanG2]

I looked at your other project as well as this one. In that project you used eneloop batteries as storage cells. They were wired in parallel, meaning that their voltage is not added together, but their current is. So if they put out just under 1.5 volts, the four of them in parallel still put out just under 1.5 volts. A lot of the boost circuits that have USB output are designed to boost an input of around 3 volts to an output of 5 volts. If the boost circuit in that project falls into that category the 1.5 volt supply may not be enough to achieve the 5 volts output needed to supply your iPhone. You might be able to correct this by making two pairs of batteries whose positives and negatives are connected, then connecting the positive side of one pair to the negative of the other. The remaining positive and negative would be connected to your solar cell and boost circuit the way the connections are made at present. This should give you enough voltage. I don't know the current requirements for the iPhone, but I've seen some light chargers work. Hope this helps!

[NeroliKo]

Thank you for reminding me about this! However, my booster module can boost an input of 0.9V-5V to 5V, so I guess wiring them in parallel (which gives me 1.2V) is not the problem(?)

[DeanG2]

That's right --if it's like the ones I just read about input voltage should not be the problem. Current out versus the current requirement of the phone?

[NeroliKo]

I think the problem is with the current output. It's less than the requirement of the phone.

[AngelaE2]

Where did you get the portable rechargable fan?! I need one of those!

[NeroliKo]

I got one from a local store in Hong Kong. But I bet you can find it on eBay or Amazon - it's called "Palm-leaf portable fan"

[AngelaE2]

Thank you I will check!