How to make a solar-powered phone charger from scrap!

No, this is not a joke — and it looks relatively straight-forward. (I could have posted this in another forum where it might have got a wider audience, but I figured it would be of more real use to the folks in here. )


Three-and-a-half minute video


Hopefully some might find this useful. And if anyone actually has a go perhaps they might even post their own video / photo.

Incidentally, I imagine similar set-ups could be created to power all manner of electronic equipment...

thats pretty neat, I would like to learn how to do that

reply to post by hapablab


You may not have to. (At the risk of killing the thread: it turns out ebay is selling solar chargers, and they're pretty cheap, too.)

Maybe the DIY method would still be good for true survival situations, though. I suppose the idea would be to stock up now on the few basic components that are required to make your own.

reply to post by pause4thought


Unless people have to abandon their areas, I would say solar panels would be fairly available...for awhile. I have scoped out several panels in my area that in the event they could be had relatively quickly. We have solar panels all over the place. Construction signs, road signs, schools etc.

reply to post by Skewed


"Scoped out" / "...they could be had relatively quickly..." Vivid euphemisms, I have to say(!)

Do you think making use of said panels is as easy as it looks in the video?

reply to post by pause4thought


Sure, if you understand it.
For small things there is not a whole lot to it.

It is all DC power unless you need to use an inverter.
I used to rip solar panels out of calculators all the time and replace the batteries with solar panels on some of my toy stompers(anyone remember those). Worked pretty good. Probably the simplest thing I have done along those lines.

reply to post by Skewed


Thanks. I was hoping someone with experience would come in. Maybe next time you do something like that you could post a clip showing how you go about it. There are probably plenty of folks who'd like to give it a go but lack the confidence. (I remember feeling very much that way when I first had to fix a PC...)

reply to post by pause4thought


My thought about survival is that knowledge and understanding how things work allow a person to "Macgyver" devices and items from scraps of debris..... that is why it is important to do more than just get supplies. Education will make the difference in the end

like getting water from wells; clean water supplies in a real emergency which are overlooked in normal conditions..

where could you get water?

or where and how can you get oil or fuel.....

I already have a solar charger for my cell that I can put in my backpack ; works great but cost a lot of money lol; but hey I'm a survivalist so I wanted it. It charges any USB powered electronics meaning my phone iPod and small gizmos will have power in the event of a blackout

reply to post by THE_PROFESSIONAL


Obviously some folks are already up to speed on this issue. But have you supplied your key contacts with the same equipment?

reply to post by pause4thought

At the risk of killing the thread: it turns out ebay is selling solar chargers, and they're pretty cheap, too.)

You right solar charger start from about 2$ on ebay

LINK TO SOLAR CHARGER EBAY

Of course you can buy the cells alone or a already made kit of different voltage suiting almost every need.

with the ultra low cost of solar cells i think its time to use solar energy for little common task... for starter.

Charging a cell phone with solar energy instead of the power grid save energy, considering millions of people have cell phone its ALOT of non-renewable ultra costly energy saved.

I know, you need sun...and like most of us i charge my cell phone during night....

Solar energy is not perfect but its a good start to try saving this planet.

If you think a little there a lot of simple things we can do with solar power.

This technology is not that hard, its barely trivial tech, so its pretty easy to understand for everyone with little knowledge of electricity and electronics.

Blueprints, how-to, ideas, build-it yourself, etc... for tons of solar powered projects are available for free on the internet.

Even better, most part you need can be scavenged from dead / no more needed / discarded electronics equipments.

I will make ( for the fun too) :

- Solar rechargeable battery charger

- Solar energy accumulator ( got some juice even at night )

- 12v general use energy block

Pretty sure its already exist but where the fun just buying it !


.

A couple of things to keep in mind...

Solar cells are not cheap (unless your company makes and sells them,of course). I managed to find a halfway decent deal on some cells about the size he is using, surplus, a while back and they were still about $3 per.

The current output from a small cell is tiny. Panels use multiple cells arranged in parallel in order to increase the current, and in series to increase the voltage. This means if you want four times the cell voltage and four times the cell current, you need 16 cells.

If you plan on continuing to use your phone indefinitely, do not use this procedure. It will charge a battery, yes, but it can also easily overcharge a battery, shortening its life span considerably. Commercial battery chargers contain circuitry to detect when a battery is charged and shut off all but the tiniest trickle of current to prevent this. Lithium-ion and NiMH cells are particularly sensitive to overcharging.

I noticed he mentioned the parts list, but never mentioned how to hook them up:

Each solar cell will have a positive and a negative side. You hook these up in an array, arranging them in series to obtain the desired voltage, and each series then in parallel to get the required current. Voltage on a single cell is usually about 0.5V, while current is roughly proportional to the area of the cell. So if you cut a cell that is rated for 10 mA current in half, expect to get about 5 mA current.

When you cut solar cells, be careful not to cut the main leads! Cut across the secondary leads.

Connect the positive lead from the solar cells to the positive lead of the capacitor, and the negative lead of the solar cells to the negative lead of the capacitor. Capacitors have a lead marked; if you are not sure about the solar cells, connect them to a voltage meter. When the voltage reading is positive, the black lead is negative.

A voltage regulator (that's an LM7805, btw) has three terminals. You'll need to identify them by the accompanying documentation if possible, but normally the middle lead is the ground. One of the others is input; the other is output. If you're using trial and error, be careful not to leave it hooked up backward too long. Those regulators are pretty hardy in comparison, but still can burn out.

Connect the ground to the negative solar panel/capacitor leads, the input terminal to the solar panel/capacitor positive leads, and the output terminal to the USB (or whatever you are using for an output jack). You just built a power supply.

The regulators come in many different voltages, with the most common being 5V, 12V, and 15V (LM7805, LM7812, and LM7815 respectively). You will need a couple volts difference between the input and the output terminal voltages... depending on the exact chip used, some regulators will not even turn on until the minimum voltage level is reached, while others will just act like a small resistor until regulation is needed.

Cost: you can find a capacitor (I would recommend 470/500 uF minimum, and at least one and a half times the maximum voltage you might ever encounter) in electronic equipment, or buy one at the local Radio Shack for under $5... less than a dollar mail order, but then you have shipping charges. The regulator, about $2 at Radio Shack, 50 cents mail order. All of the cost is in the solar cells.

One more thing: if you plan on doing this, get a soldering iron, not a soldering gun! Bigger does not mean better when it comes to soldering! 25-35 watts is more than enough (I could do all that with my 12-watt precision iron). Also make sure you use rosin flux solder; acid flux will destroy your parts.

TheRedneck

reply to post by TheRedneck


Thank you very much great post, save me some research time on the net.

If you plan on continuing to use your phone indefinitely, do not use this procedure. It will charge a battery, yes, but it can also easily overcharge a battery, shortening its life span considerably. Commercial battery chargers contain circuitry to detect when a battery is charged and shut off all but the tiniest trickle of current to prevent this

So i will include the circuitry in my solar charger to prevent the problem. i can take the one inside the commercial charger but i will make one from scratch to add fun.

BUT

Cell phone can be charged by a PC via the USB port. Is there a control chip / usb specs that prevent overcharging of cell phone or any devices on a computer chipset ?

The usb cord for connecting the phone to the pc content no circuitry, its plain wire. USB to MicroUSB

So is the phone maker Cie let us damage our battery purposely ?

Searching to see if the controller is now included in the smart phone OS directly.

.

reply to post by B3lz3buth

Make sure you don't exceed the maximum input voltage on that circuitry; other than that, it will probably work.

If you go the build from scratch route, the biggest problem you will likely have is the physical size of some of the chips used to regulate charge. I'd invest in a good pair of tweezers and a powerful magnifier.

That said, STMicro makes a nice simple little charge regulator chip, the STC4054. It's still pretty small, being in a SOT23-5 package, but it's much larger than some of the other ones available. At least a micro-tip on a small iron will reach the leads... and at least it has leads instead of bumps to solder to.

No idea on a source. Mouser Electronics shows it as non-stocked, 16 week lead time.

TheRedneck

reply to post by B3lz3buth

USB is a tightly regulated 5V supply. That's a good point; if it is designed to take USB charge, the charge regulation would be built into the device.

That LM7805 should work just fine for a USB supply.

TheRedneck

reply to post by TheRedneck

I'd invest in a good pair of tweezers and a powerful magnifier.

Oh yes, tiny, tiny little pieces... at least i don't have shaky hands...

STC4054 and LM7805 are perfect for the jobs thanks.

.

reply to post by pause4thought


Yea they don't have any of this equipment; I also keep a power inverter in my vehicle and I encourage people to do the same in the event of an outage. I made a thread on my survival kit here:

www.abovetopsecret.com...

reply to post by THE_PROFESSIONAL


I was just thinking 'there's not much point having a mobile that works in all scenarios if those you want to contact can't charge their phone'.

Incidentally Samsung's Solid Immerse might be of interest to some.

...the mobile operates up to 1 meter underwater and can stay submersed for up to 30 minutes.

I hear there are also some that have dual simcards.

Beyond that it's clear from what some posters have said that solar power has the potential to keep quite a range of equipment functioning. (I'm intending to look into the possibilities for myself over the next few days.)

As for imitating your kit list — all I can say is 'I hope Santa's generous this year.'

reply to post by pause4thought


You can also take an old box fan and an alternator from a car and with some rework you can have you a small windmill as well.

reply to post by pause4thought

Almost anything that operates on small batteries can be powered by solar. Modern electronics uses such small currents that solar power can supply them, at least for short periodic use.

One thing to consider, however, is that these devices do not operate completely independently. Last April, my area had some pretty severe tornado damage, and while cell phones did work, many of the cell towers were down or overloaded. I managed to get some calls in (in large part to my ability to revive some 'dead' inverters and charge them from my car), but calling out was almost impossible. Not only were the towers too busy to take another connection most of the time, but signal strength was very spotty. It takes more signal to call out than to receive a call.

Know the technology, use the technology, but never completely depend on the technology for survival.

TheRedneck