This is my take on a already well documented little project. Very simple to make and a good introduction to electronics and solar powered stuff. Works just fine too. You need to generate 5-6V to charge a phone.
You will need:
Solar panels. I used 2 panels. (3V I think )
5V voltage regulator
USB female jack/connector
Insulated wire
Soldering Iron
Epoxy or hot glue
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Gather together all your stuff. You need to make sure you know which side is top and which side is the bottom of the USB plug and the voltage regulator so that you solder the correct pins.
The regulator keeps the power output to 5v.
The regulator keeps the power output to 5v.
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Maybe LG like the evil Apple empire and the phone needs a data connection in order 'to know' its connected and will then beging charging??
will a 0.5watt panel work?
I just got five 3.3 Watt 6 Volt Solar Panels for 20 bucks. Granted there not small and light like the ones listed but there great for starting and testing a DIY project before spending a lot on these nice little ones.
I mean this is nice if you want to leave your phone or the charger in a sunny position and only use the phone for like 10 or 15 minutes a day - great.
But the sheer lack of "current" in milliamperes is it's fundamental limitation.
I use a similar set up with a 10W 12V solar panel, to keep 3 big car batteries charged up or protected against self discharge, as they only get about 3 watts into each individual battery for about 4 or 5 hours a day.
But if the batteries were used to supply any real power to anything - it's going to take MONTHS to charge them up, that being the rate of self discharge and the amount of power needed to be put back into them.
But as a float charger - it's a good set up.
Same goes for this - mainly OK for low use products or low power use products.
So while the charge bars show "charging" that is the device is hooked up to a higher voltage supply than the voltage level of the internal battery, it may not actually be showing that the battery is really charging relative to the amount of current being drawn and the amount of current going into the battery.
This is an effect I noted with inverters running from 12V batteries, in that they stop drawing power when the battery voltages drop to 10 or 10.5V, but by adding a small charger to the battery, it raises the voltage of the cells while putting in hardly any power, and the voltage sensor in the inverter reads the batteries as being fully charged.
So you can keep drawing heaps of power from a partially discharged 12V battery, by the super imposition of a voltage over the batteries real voltage.
Not recommended to do this - but this is what you may be getting on the charging bars, reading in that the battery is charging when the device is pulling more power from the battery than the charger is putting in.
It may be a case of simply slowing the discharge a little more than anything.
Again - not volts, but milliamps - how much does the device draw when fully active, in stand by or when off - vs. the amount of current actually being put into it.
5.25 v input
5v output
1amp
I built the charger but I don't think I am getting enough voltage. I am using two 3 volt cells and I put them under a bright spiral CFL bulb and it can hardly light a very bright LED. My phone and other devices are not being charged. Any tips?
I am going to try putting it under the sun tomorrow.
How did it go in the bright sun?
Okay, I'll stick to incandescent bulbs. I am using a USB hub with a bright blue LED as my load. On a sunny day, the LED was much brighter than indoors, but not as full as when the hub is plugged into a USB port. Even in the sun my phone isn't getting charged. I am currently using two 3 volts cells but I own four. Do you think it would work if I used three or maybe all four cells? (My only worry is that the regulator will not be able to handle 9-12 volts and it might get fried.)
Neat i'ble! I love solar gadgets!
I don't think the reverse flow will damage the phone's battery...just drain it. (?) But to be on the safe side, a diode connected to the positive from the panels could be a safe bet. Isn't there a bit of a voltage drop tho? I'm working this stuff out as I go.
Cheers for the comments!
I'm from Uruguay .. If you know that maximum solar cell gives 5 volts. not ever require anything.
I put my cell 5 volts directly with a 1N4007 diode or similar just for safety.
I saw that the solar cell without the diode calienta.Lo another bear in mind that we have 5 volts but the amps?. Minimo 100 or 150 milliamps need to show that the loading, the majority of small cells are only 80 milliamps, my advice is cell buy 8 or 12 volts and 150 milliamps or 200 or put 2 ceeldas of 5 volts and then put 5 volts regulator LM7805. Greetings ..
Je Kan
You could try http://www.solarbotics.com/
I lived in Tokyo for a few years, Tokyu Hands dont carry solar cells? (It is the greatest shop on earth after all!)