One of the most fun and useful projects on instructables is to create your very own solar USB/ iPhone charger. They're not overly difficult to make, nor are the parts overly expensive or hard to find. For the most part they do a rather good job of charging up small gadgets. Mostly.
The big flaw in the DIY solar charger world are the batteries. Nearly all the designs on instructables (including all of my designs) use standard NiMh rechargeable batteries. They're cheap, easy to find, and very safe to use. The problem is that their capacity and voltage are both low, and the gadgets we keep wanting to charge are getting bigger and better batteries.
For instance an iPhone 4 has a 2,000mAh battery inside of it. Now that isn't too tough to charge up decently with a well made solar charger using 2 or 4 AA batteries. On the other hand an iPad 2 has a 6,000mAh battery pack on it. Not so easy to charge up.
The solution for these problems is to ditch NiMh batteries and turn to Lithium batteries.
In this guide I will show you how to make your very own Lithium battery charger. One that is cheap to make, easy to build, and most importantly safe to use.
(Oh and help me win the Instructables Green Tech Contest by voting for this project! An iPad would be great for my classroom! Even better, I'll build a massive Lithium powered charger to run the iPad. It'll be 100% green in my classroom.)
The big flaw in the DIY solar charger world are the batteries. Nearly all the designs on instructables (including all of my designs) use standard NiMh rechargeable batteries. They're cheap, easy to find, and very safe to use. The problem is that their capacity and voltage are both low, and the gadgets we keep wanting to charge are getting bigger and better batteries.
For instance an iPhone 4 has a 2,000mAh battery inside of it. Now that isn't too tough to charge up decently with a well made solar charger using 2 or 4 AA batteries. On the other hand an iPad 2 has a 6,000mAh battery pack on it. Not so easy to charge up.
The solution for these problems is to ditch NiMh batteries and turn to Lithium batteries.
In this guide I will show you how to make your very own Lithium battery charger. One that is cheap to make, easy to build, and most importantly safe to use.
(Oh and help me win the Instructables Green Tech Contest by voting for this project! An iPad would be great for my classroom! Even better, I'll build a massive Lithium powered charger to run the iPad. It'll be 100% green in my classroom.)
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Signing UpStep 1: What you need
Electronics Parts:
5V (or greater) Solar Cell
3.7V Lithium Ion Battery
Lithium Battery Charge Controller
DC-DC USB Boosting Circuit
2.5mm Female Panel Mount Plug
2.5mm Male Jack with Wire
1N4001 Diode
Wire
Building Supplies:
Electrical Tape
Shrink Tubing
Double Sided Foam Tape
Solder
Altoids Tin (Or other enclosure)
Tools:
Soldering Ion
Hot Glue Gun
Drill
Dremel (Not necessary but good to have)
Wire Cutters
Wire Strippers
Helping Hand
Safety Goggles
This guide will show you how to make a Solar powered version of this charger. You can also easily ditch the Solar section completely and rely on USB to charge up the Lithium battery.
While many of the parts for this project can easily be found at most online electronics store, a few items like the "DC to DC Boosting Circuit" and the "Lithium Charge Controller Board" are more difficult to find. As this guide continues I'll provide you with several options on where to get most of the parts as well as a detailed rundown of what each one does. Then you can make an informed decision as to which one best meets your individual project needs.
As a disclaimer I will say that I do sell both finished versions of this charger, parts to make this charger, and complete kits on my website BrownDogGadgets.com. You don't need to get these parts from me, and I'll be showing you several other places to buy the parts at in case what I have doesn't meet your needs.
5V (or greater) Solar Cell
3.7V Lithium Ion Battery
Lithium Battery Charge Controller
DC-DC USB Boosting Circuit
2.5mm Female Panel Mount Plug
2.5mm Male Jack with Wire
1N4001 Diode
Wire
Building Supplies:
Electrical Tape
Shrink Tubing
Double Sided Foam Tape
Solder
Altoids Tin (Or other enclosure)
Tools:
Soldering Ion
Hot Glue Gun
Drill
Dremel (Not necessary but good to have)
Wire Cutters
Wire Strippers
Helping Hand
Safety Goggles
This guide will show you how to make a Solar powered version of this charger. You can also easily ditch the Solar section completely and rely on USB to charge up the Lithium battery.
While many of the parts for this project can easily be found at most online electronics store, a few items like the "DC to DC Boosting Circuit" and the "Lithium Charge Controller Board" are more difficult to find. As this guide continues I'll provide you with several options on where to get most of the parts as well as a detailed rundown of what each one does. Then you can make an informed decision as to which one best meets your individual project needs.
As a disclaimer I will say that I do sell both finished versions of this charger, parts to make this charger, and complete kits on my website BrownDogGadgets.com. You don't need to get these parts from me, and I'll be showing you several other places to buy the parts at in case what I have doesn't meet your needs.
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I made my charger very similar to this, Im using a 4000ma 14.8wh LIPO
I am using 2 6v 250ma and one 5.5v 320ma solar cells. Can i wire these in parallel to get an ending amperage of 820ma? I know the voltages don't exactly match up, but its close.
my real issue is that my charging circuit wont add power to my phone (android rezound) . I have tried turning it off when i charge and letting it sit for a long time. The charge light on the charge controller and my phone light up acknowledging that it is charging but when i check my phone's battery is lower than when i started. I am using a 1n4001 diode on both the solar input and the usb output to prevent back charging. am i doing this wrong?
i have been charging the lipo from micro usb
ill attach photos for help.
Or is that approach simply too naive? :)
also what size is the lithium battery..well what would be the most appropriate size?
The problem could be that your gadget is using up more power than what is being put into it. If you're using GPS, listening to music, and have the screen on full brightness you're using up a lot of power really quickly.
Your'e just sucking power away before it even hits the battery.
please reply to me
my s3 battery is 3.8v 2100 mAh
I had everything wired correctly, so I tested it out and it said my phone was fully charged when it really wasn't.
I checked the voltage again and it had dropped to something like 1.7v. I tried a new battery and the same thing happened- fine at first but once it's used, the voltage dropped.
What could have caused this? Thanks.
Jake
The big reason for a battery is so you can store up a charge for later. Mostly because people tend to charge at night, not during the day.
Also because solar is very inconsistent. The power levels fluctuate throughout the day, or even minute to minute. Having a battery in the mix just really helps smooth things out.
(The believe iPad 3 has a 12,000mAh battery inside. Seriously. It's huge.)
I am just starting with electronics but just to confirm , if I use a 6600 mAh li battery or even a regular battery and solar charger, won't I be able to charge it completely in the day due to the constant solar power ???
Would that be possible?