how to make a solar ipod iphone charger aka might
TRANSCRIPT
http://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/
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How to make a solar iPod/iPhone charger -aka MightyMintyBoostby Honus on May 2, 2009
Table of Contents
License: Attribution Non-commercial Share Alike (by-nc-sa) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
Intro: How to make a solar iPod/iPhone charger -aka MightyMintyBoost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
step 1: Tools and materials . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
step 2: Build the Minty Boost kit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
step 3: Add the battery and charger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
step 4: Add the solar cell . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
step 5: FAQ and additional info . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Related Instructables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
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http://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/
License: Attribution Non-commercial Share Alike (by-nc-sa)
Intro: How to make a solar iPod/iPhone charger -aka MightyMintyBoostI wanted a charger for my iPodTouch and the MintyBoost was definitely my first choice. I wanted to take it a bit further and make it not only rechargeable but also solarpowered. The other issue is that the iPhone and iPodTouch have large batteries in them and will deplete the two AA batteries in the MintyBoost rather quickly so I wantedto increase the battery power as well. What I really wanted was a MightyMintyBoost!
Apple has sold over 30 million iPodTouch/iPhone units- imagine charging all of them via solar power.... If every iPhone/iPodTouch sold was fully charged every day(averaging the battery capacity) via solar power instead of fossil fuel power we would save approximately 50.644gWh of energy, roughly equivalent to 75,965,625 lbs. ofCO2 in the atmosphere per year. Granted that's a best case scenario (assuming you can get enough sunlight per day and approximately 1.5 lbs. CO2 produced per kWhused.) Of course, that doesn't even figure in all the other iPods, cell phones, PDAs, microcontrollers (I use it to power my Arduino projects) and other USB devices thatcan be powered by this charger- one little solar cell charger may not seem like it can make a difference but add all those millions of devices together and that's a lot ofenergy!
There are some really nice features about this charger:
It's solar powered!It's small.Large battery capacity- 3.7v @2000mAhOn board charger charges via solar, USB or wall wart. Accepts input power from 3.7v to 7v.Remove the solar cell after charging and you have a nice compact USB power supply.Unplug the solar cell and use the Velcro to secure the MightyMintyBoost inside a backpack or messenger bag- now plug in a larger solar cell attached to your bag foreven faster charging. Using a slightly larger solar cell (6v/250mAh) you can generate enough power to fully charge an iPhone in about 5.5 hours and an iPod Touch in 4hours.
Building this is really easy and straightforward- it only took me around an hour so follow along and build one for yourself!
Safety note and general disclaimer: Be careful cutting the Altoids tin as it can have some really sharp edges- file them smooth if necessary. Assemble this at your ownrisk- while it is really easy to build, if you mess something up there is the potential to damage the electronic device you are trying to charge. Be careful in your assemblyand soldering work and follow good safety practices. Only use a type of battery charger specifically designed for the type of battery you are using. Please read throughthe entire Instructable before asking questions- if there are are any questions just ask and I'll help out as best as I can!
Image Notes1. iPodTouch- it's charging!
Image Notes1. Charging on solar power!
http://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/
Image Notes1. Arduino w/Adafruit Wave shield powered over USB
step 1: Tools and materialsHere's what you'll need to build your own MightyMintyBoost:
Tools:Soldering ironScissorsWire cuttersPliers (or muiltitool)MultimeterMetal shearsClear packing tape
Materials:MintyBoost kitLithium Polymer battery charger3.7v 2000mAh Lithium Polymer batteryJST connector/wireSmall solar cell2" x 3" adhesive backed VelcroSmall double sided adhesive squaresAltoids tin
7/10/10 UPDATE: Adafruit now also sells all the parts you need to make this a bit more mighty. Have a look here!http://www.adafruit.com/blog/2010/07/09/how-to-make-a-solar-mintyboost-a-solar-power-charger-for-your-gadgets/
Some notes:
The single cell Lithium Polymer charger can accept input power that ranges from 3.7 to 7v maximum. When the cell reaches full charge the charger will automaticallyswitch to trickle charging. When charging using the mini USB port, the charging current is limited to 100mA. When charging using the barrel plug jack, the chargingcurrent is limited to 280mA.
The solar cell maxes out at approximately 5v @ 100mA in bright sunlight. If you need faster charging simply use a larger solar cell- a 6v cell @ 250mA would work verywell and they are easily obtainable and inexpensive. I used the size of solar cell that I did because I wanted it to be super compact.
I could not find out from the manufacturer if the solar cell I used has a blocking diode. A blocking diode is used in many solar charging systems to prevent the solar cellfrom draining the battery during low light conditions. Instructables member RBecho pointed out that the charging circuit used negates the need for a blocking diode in thisapplication. You can tell when the solar cell is producing enough power because the little red LED on the charger will come on during charging.
Image Notes1. 3.7v 2000mAh LiPoly battery2. double sided adhesive squares3. Velcro4. trusty multitool5. JST connector6. Sparkfun single cell LiPoly charger7. Adafruit MintyBoost kit8. Sparkfun small solar cell9. multimeter
Image Notes1. My trusty soldering iron
http://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/
step 2: Build the Minty Boost kitFirst build the MIntyBoost kit according to its instructions. It's really easy to assemble- even a complete novice can do it.
Instead of connecting the battery holder in the kit, we're going to solder a JST connector to the MintyBoost PCB. This tiny connector will then allow the MintyBoost circuitto connect to the Lithium Polymer battery charger circuit. Make sure you get the polarity correct!
Test the MintyBoost by connecting the battery pack (make sure the battery pack has a charge) and charger circuit. The MintyBoost connects to the connector markedSYS on the charger board and the lithium polymer battery connects to the connector marked GND.
Now cut a notch in the Altoids tin for the USB port and use some double sided adhesive to mount the PCB to the Altoids tin.
Image Notes1. JST connector2. MintyBoost PCB
Image Notes1. 3.7v 2000mAh Lithium Polymer battery2. Sparkfun single cell Lithium Polymer battery charger
Image Notes1. battery goes here2. MintyBoost goes here3. USB power in4. 3.7 to 7v power in
Image Notes1. cut notch for USB socket
http://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/
Image Notes1. Adhere MIntyBoost PCB with double sided tape
step 3: Add the battery and chargerNow cut a notch out of the other side of the Altoids tin to fit the charger and secure the charging circuit to the bottom of the Altoids tin with double sided adhesive.Reconnect the battery and the MintyBoost PCB to the charging circuit. Make sure nothing on the bottom of either one of the circuit boards is touching the bottom of theAltoids tin.
step 4: Add the solar cellThere are a couple of different ways to connect the solar cell. The first is by simply shortening the connector leads and plugging the barrel plug into the barrel jack on thecharging circuit.
The second method is to replace the connector with another JST connector and plug it into the third connector marked 5v on the charging circuit. I didn't have anotherJST connector handy so I just soldered a salvaged two pronged connector to the charging circuit where there are two open pins on the 5v line.
Using the second method certainly is a bit cleaner since you don't have the big barrel plug sticking out of the side of the tin.
Now attach the solar cell to the top of the Altoids tin using some 2" wide Velcro. I wrapped the battery pack with a layer of clear packing tape to help protect it. Then thebattery pack is simple set down on top of the two circuit boards- it's a near perfect fit.
Now set your MightyMintyBoost out in the bright sun and charge it up! You should see a little red LED on the charger board light up. Once it's fully charged connect youriPod/iPhone/USB powered device and enjoy!
http://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/
http://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/
step 5: FAQ and additional infoHere's a list of frequently asked questions:
Q: Is it possible to overcharge the Lithium Polymer battery?A: No- the charger will automatically switch to trickle charging and then shut off.
Q: Is it possible to drain the Lithium Polymer battery completely and damage it?A: No- the battery has its own low voltage cut off circuitry that will prevent it from completely discharging- the low voltage cut off is around 2.8v
Q: Does the solar cell have a blocking diode to prevent it from draining the Lithium Polymer battery?A: No blocking diode is necessary- the Lithium Polymer charger prevents the battery from leaking current.
Q: How long will it take to fully charge the Lithium Polymer battery and how long will it take to charge my iPod/iPhone?A: How long it will take to fully charge depends on the amount of sunlight available but as a rough guesstimate it would take around 20hrs using the small solar cell indirect sunlight. Using a larger solar cell could easily take half if not one third the amount of time. Those same figures would apply if you were charging it over USB orusing a wall wart power supply.
Charging your iPod is much faster. How fast it does it depends on your device's battery capacity. An iPod Touch has a 1000mAh battery so it should fully charge it inaround 2hrs. A 3G iPhone has a 1150mAh battery so it will take slightly longer and a 2G iPhone has a 1400mAh battery, so it will take around 3 hrs.
Q: The Lithium Polymer charger has an input voltage range of 3.7v minimum to 7v maximum- what if I want to use a higher output solar cell for fastercharging?A: To use a solar cell with a voltage output greater than 7v, you need a voltage regulator to drop the voltage to a level that the charger can handle. You could use a 7805voltage regulator to limit the output to +5v -they only cost about $1.50 and are very simple to wire up. The 7805 will give you as fixed +5v and is usually good up to 1Acurrent. You could also use a LM317T which is an adjustable regulator, but it would involve a bit more circuitry to use. Some people also use diodes to drop voltage,since many diodes have a voltage drop of .7v
There's a lot more info here: http://en.wikipedia.org/wiki/Linear_regulator
The other option would be to use a 6v/250mA solar panel. This will stay within the current input range and voltage input range of the Lithium Polymer charger. Rememberthat you can also connect smaller solar cells in parallel to increase the available current- two 5v/100mA solar cells connected together in parallel will give an output of 5v@200mA
Q: What if I want to use a charger with a higher input current limit?A: Sparkfun does have a Lithium Polymer charger that maxes out at 1A:http://www.sparkfun.com/commerce/product_info.php?products_id=8293
Q: How would I connect the more powerful charger- there doesn't appear to be a clear way to do this?A: To use the more powerful 1A charger you would need to wire a two way switch to the battery so that in one position the battery would be connected to the charger andin the other position the battery would be connected to the MintyBoost circuit.
Q: Will this work with USB devices other than iPods and iPhones?A: You bet! There's a list here: http://www.ladyada.net/make/mintyboost/
Q: Won't the inside of the Altoids tin short out the circuit?A: No- using double sided foam tape to mount the circuit boards keeps the bottom of the board from coming into contact with the inside bottom of the tin. If you're reallyworried you can cover the inside bottom of the tin with clear packing tape.
Q: How much does this cost? Can I build it for less? Is it cost effective?A: If you buy everything as listed it would cost $70.75 (not including the Altoids tin or shipping.) If you wanted to scratchbuild it using the MintyBoost PCB from Adafruit,building your own charging circuit and supplying your own parts from various sources you can save quite a bit. Both the charging circuit and the MintyBoost circuit areavailable online- just go to the web pages listed in the tools and materials section- they're also listed at the bottom of this page.
Both Maxim and Linear Technology supply free samples (according to their websites) of their ICs so you just need to provide all the other bits (available from places likeMouser and Digikey.) Using a slightly smaller solar cell and a 2200mAh battery it is possible to build it for a lot less:
2200mAh batterysolar cellMintyBoost PCB
http://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/
After adding up the small parts for the MintyBoost circuit, a small blank PCB for the charging circuit (you would have to etch the board yourself) and a mini USBconnector, you could conceivably build this for around $21.00 (not including shipping or an Altoids tin.) It wouldn't be exactly the same of course, but it would befunctionally the same. I don't know if the 2200mAh battery would fit into an Altoids tin either. It would be a LOT more work of course, and there could be a fair bit oftroubleshooting if you're not experienced in building these types of circuits or soldering surface mount components.
So is it cost effective? Absolutely- it just depends on the amount of work you want to do. Either way, you get a very useful and versatile solar powered charger.
Q: How did you calculate the power usage and equivalent CO2 values?A: Here's the math-3.7v (LiPo rated voltage) x .1A (solar charge current)= .37W.37W x 12.5hrs (charge time based on average battery capacity) = 4.625Wh4.625Wh x 365 days = 1688.125Wh per year1688.125Wh per year x 30,000,000 units sold = 50,643,750,000Wh total used per year (50.644gWh)50.644gWh per year x 1.5 lbs CO2 produced per kWh used = 75,965,625 lbs. CO2 produced per year
Granted these are more or less maximum values but they clearly show some potential for some serious energy savings. A 12.5hr solar charge time per day isn't realisticfor the majority of the planet but if you shorten the solar charge time to approximately 4.5hrs at a 280mA current the results still remain the same.
General information about the Lithium Polymer charging circuit as well as a circuit diagram and data sheet can be found here:http://www.sparkfun.com/commerce/product_info.php?products_id=726
A complete description and documentation of the MintyBoost circuit can be found here:http://www.ladyada.net/make/mintyboost/
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Solar iPhoneCharger forunder $50. byakbrennan
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Comments50 comments Add Comment view all 623 comments
stukz says: May 27, 2010. 6:57 AM REPLYwhat is the total coast of all the parts?
Honus says: May 27, 2010. 10:13 PM REPLYLook in the FAQ section- it's all there.
Gideon Ackon says: Jul 26, 2010. 9:24 AM REPLYfrom you, i know how to make any scientific project
T8tersalid says: Jul 4, 2010. 10:11 AM REPLYHow much does this weigh? I will be going on a hiking trip for a week in Yellowstone, and I will need to recharge my camera so it doesn't run out of battery?If it's somewhat heavy, would there be anyway to make it lighter?
Honus says: Jul 4, 2010. 12:13 PM REPLYI don't know the exact weight but it's pretty darn light. I'd guess it's somewhere between 50 to 100 grams. I no longer have mine so I can't weigh it. I'm inthe process of making a new one that is thinner and lighter using SMD components.
T8tersalid says: Jul 4, 2010. 12:47 PM REPLYOk thanks! I'll be making this very soon!
http://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/
Honus says: Jul 19, 2010. 7:02 PM REPLYJust weighed my new super small version that fits in an Altoids mini tin and it weighs 39 grams but that doesn't include the solar cell, whichweighs 25 grams.
MrChipify says: Jul 23, 2010. 10:51 AM REPLYAre you going to post how to make your newest version?
Honus says: Jul 24, 2010. 8:32 AM REPLYYep! I just finished the board design so I can have PCBs made. That way people can purchase bare PCBs from the manufacturer andsolder them themselves. The board measures 1.50" long by 1.25" wide so it's pretty small. I redesigned it so both of the USB connectorsand LED are on the same end of the board, which makes it easier to access the ports. The home made board just barely fits in the miniAltoids tin but because of the height of the mini USB cable connector you can't keep the lid closed while the cable is connected- that'swhy I moved both USB ports to the same end. The unfortunate side effect is that this board would be pretty darn difficult to make at homebecause of the way it's routed and the vias needed to connect the top and bottom copper layers. I still need to proof the design and sendit to the manufacturer so it'll take around a month to get the boards made, take photos and post everything.
MrChipify says: Jul 23, 2010. 10:50 AM REPLYI built mine and it worked great, but now the battery either isnt chargeing or wont hold a charge. has this happened to anyone eles? thanks
Honus says: Jul 24, 2010. 8:13 AM REPLYIt sounds like you have a bad battery. I'd contact Sparkfun (or wherever you purchased your battery.)
MrChipify says: Jul 23, 2010. 10:33 PM REPLYany suggestions??
13blue says: Jul 22, 2010. 2:09 PM REPLYAdafruit has a Lithium Ion Polymer Battery - 1200mAh, its a little cheaper and would save a shipping charge. Would it be ok to use rather than the2000mAh?
Honus says: Jul 22, 2010. 6:12 PM REPLYSure. It just won't have as large a capacity so it might not fully charge your device. I just built a charger using a 1100mAh cell and it works just fine. Thebenefit of a smaller battery is that you can make the charger a bit smaller.
mdelzo says: Jul 21, 2010. 8:48 AM REPLYHello, Say that I charge my cellphone with four AA batteries which gives an output of 4.8V and the input of my cellphone is 3.7 V with 950mAh. will this frymy cellphone?? thank you
http://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/
Honus says: Jul 21, 2010. 3:45 PM REPLYDoes you cell phone charge over USB?
mdelzo says: Jul 21, 2010. 6:00 PM REPLYwell i have a USB connector for the computer which i can also use to charge it (thru my computer)
Honus says: Jul 21, 2010. 6:17 PM REPLYUSB is 5V so if you're trying to use 4.8V then it won't fry it. Much of it depends on how you're trying to charge it (is the voltage stable), how muchcurrent the phone will pull during charging (batteries can only provide so much current), etc. Many devices that are charged over USB requiresome interaction over the USB data lines so it isn't always as simple as connecting some batteries to your phone through the USB port.
icecreamterror says: Jul 4, 2010. 6:19 AM REPLYWould be nice to see this in true DIY form....without having to buy all the integral parts in a kit from SparkFun, really expensive for people out side the US :(
Honus says: Jul 19, 2010. 6:58 PM REPLYHere's the DIY version I just made for my brother in law- works like a charm. It uses surface mount components and I etched the circuit board at homeusing the toner transfer method. Considering I haven't etched a circuit board in 20 years it came out OK -but could be a whole lot better! It's super smalland I could make it smaller if I had a board house make my PCB but it's really not necessary as it's already smaller than the 1100mAh LiPo batteryfootprint. The 1100mAh cell was the largest that would fit in the mini Altoids tin. I'd actually prefer it if the board was more narrow and longer- that wouldmake the ports easier to access. I've already designed a new board for a board house to make so it'll be nice and professional looking next time. :)
Honus says: Jul 4, 2010. 9:36 AM REPLYThe big problem with that is most people don't have the ability to make their own circuit boards. All the info is there and the individual parts are readilyavailable. Both Adafruit and Sparkfun provide schematics and EAGLE files so there's absolutely nothing to stop you from making the entire thing fromscratch. I'm currently making a super small/slim version from scratch for my brother in law for his birthday.
MrChipify says: Jul 7, 2010. 3:57 PM REPLYHey Honus,will this charger work on th Iphone 3Gs? thanks
Honus says: Jul 19, 2010. 6:44 PM REPLYI forgot this: http://www.adafruit.com/blog/2010/02/08/using-the-iphone-3gs-with-a-mintyboost/
Honus says: Jul 8, 2010. 6:01 PM REPLYYes and no- the 3Gs is very finicky about its data line interaction. Have a look at the MintyBoost FAQ section:http://www.ladyada.net/make/mintyboost/faq.html
chickflix says: Jul 19, 2010. 4:02 PM REPLYwould this work with a Nook?
Honus says: Jul 19, 2010. 5:58 PM REPLYNo idea. There's one way to find out...
nerdstrap says: Jul 15, 2010. 8:19 AM REPLYMy lithium battery seems to have some kind of drain on it. I see in Q&A #3 you say the Lithium Polymer charger prevents current leak. Are there otherpossible points for drain on the battery?
http://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/
Honus says: Jul 15, 2010. 6:11 PM REPLYNot unless you leave a device connected to it. All batteries will have some loss over time but the LiPos are pretty good in this regard- it should lose lessthan 8% per month.
Zansion says: Jul 9, 2010. 9:53 PM REPLYI love the project, an easy five stars but I have one question. I'm going to be getting a 160 GB iPod Classic. My thought is that it has a large capacity forholding whatever the heck I want and it would be great for camping, or a zombie outbreak. My problem is the Classic wont charge with USB power(according to Wikipedia). Would there be a way to make a fire wire version of this?
Honus says: Jul 10, 2010. 8:46 AM REPLYIs this the one you mean: http://www.apple.com/ipodclassic/specs.html That one uses USB. If it's the old first generation Firewire 400 iPod then that's adifferent story. Hmmm... that's a good one. You could make a short Firewire 400 to USB power adapter cable. There's a page here that shows thepinouts: http://pinouts.ru/Slots/ieee1394_pinout.shtml You would still have to figure out the power requirements and data interaction. That's assumingthey would charge using 5v power.
Zansion says: Jul 12, 2010. 8:25 PM REPLYYeah, that is the iPod I'm looking at, I just read on Wikipedia somewhere that all of the Classics ran on Firewire. Thanks for clearing that up for me! .z
futuresoccerstar96 says: Jul 7, 2010. 11:17 AM REPLYwhere would you get the 3.7v 2000mAh lipoly battery?
Honus says: Jul 8, 2010. 6:02 PM REPLYSparkfun- there's a link on the Tools and Materials page.
futuresoccerstar96 says: Jul 9, 2010. 11:37 AM REPLYoh, thanks
dh405 says: Jul 4, 2010. 12:15 PM REPLYSeems odd to build this at such a cost when you can buy the same thing in a pretty decent little package for $18 on DealExtreme.http://www.dealextreme.com/details.dx/sku.8222
Honus says: Jul 8, 2010. 5:59 PM REPLYWhen I originally wrote this all the solar chargers were about $80 and were limited in performance and connectivity. From what I've read some of the lessexpensive chargers are a bit hit and miss in terms of quality and what devices they work with. By building it yourself you can tailor it to your needs. If youcan make your own PCBs you can actually build this for about $21 (see the FAQ section.)
uberdum05 says: Jul 5, 2010. 9:46 AM REPLYif you are using a bigger solar panel that's voltage exceeds the maximum voltage of the charge controller, you could buy a DC-DC converter that will bring12v down to 5v at a very efficient level. Have a look at these : http://www.active-robots.com/products/power-supplies/09160.shtml (10-14V step down toprogrammable voltage through resistor)
larsrc says: Jul 7, 2010. 11:54 AM REPLYThank you for pointing these out, I really don't like the idea of just burning excess voltage into heat. However, notice that the efficiency drops radicallywhen you get down to about .5A.
bearcats2010 says: May 8, 2010. 6:41 PM REPLYyou can buy the whole thing at makezein.com for 20 bucks
camiller says: Jul 7, 2010. 6:37 AM REPLYExcept that is just a minty boost kit without the solar cells, higher capacity battery, Li-PO battery charging circuitry, etc. What Honus has here is a stepbeyond that kit.
Kasm279 says: Jul 4, 2010. 8:44 AM REPLYI would use Li-Ion or Ni-MH batteries, I've heard very bad things about Li-PO.
Honus says: Jul 4, 2010. 9:06 AM REPLYLiPo is essentially the same electrochemistry as Lithium Ion except it tends to be a bit more stable due its construction. If anything it is safer than Li-Ion.http://www.ultralifebatteries.com/engineers.php?ID=4
http://www.instructables.com/id/How-to-make-a-solar-iPodiPhone-charger-aka-Might/
Kasm279 says: Jul 4, 2010. 4:48 PM REPLYI was just using Li-Ion as something else, first battery type that popped into my head. Anyway, i think i would still have used Li-Ion because hey seemtop be less prone to bursting into flame when overcharged or overheated.
nerys says: Jul 4, 2010. 12:17 PM REPLYI have had very LOW performance results using solar panels to directly charge USB style devices. how can you charge a 1000mah battery in 2 hours using ashort circuit max full sunlight 100mah panel? even if you got the theoretical 100mah output it should take at least 8-10 hours to recharge the 1000mahbattery pack. what am I missing? I have some nice 410mah panels and even those are lackluster (my next step is to daisy chain them to get an over 800mahpanel) my GPS will "stay" charges on solar but if its more than 20% depleted the panel can NOT recharge it. My blackberry says charging but actuallydepletes faster on the solar panel than off (I am assuming I am awakening some power usage as the phone attempts to charge but its not getting enough soit just ends up using more power than its getting) My Bluetooh G5 seems to like the solar panel just fine. have not had to plug it in for over 3 weeks and itsstill going strong. my next step is more power. I think we are going to need at least 600mah of solar panels to get any sort of reliable charging done. maybethe ipods are more accepting of odd charge levels? (I have not tried to charge my nano like this yet)
Honus says: Jul 4, 2010. 1:52 PM REPLYYou can't really charge directly from a small solar cell- that's what the battery is for. The solar cell trickle charges the LiPo battery and the LiPo chargesyour USB device. That way you leave you leave the solar charger out in the sun and let it charge during the day. At night bring it in and charge your USBdevice.
nerys says: Jul 4, 2010. 3:26 PM REPLYI know but I hate that method. one more battery to replace. I want to find that magical value of minimum solar panel needed to charge "directly" fromthe solar panel. I was hoping the 410mah panel would be enough. it is for some but not for most. this way it will be maintenance free and selfcontained for 25-30 years. with a battery pack every 2-3 years I will be replacing that battery. If I go the battery route I want to go AA route usingnimhs. cheap and easy to replace and longer lasting. I usually get 5-7 years out of nimhs. but now I understand how you are charging in 2 hours :-)makes a lot more sense now. (have not gotten around to reading the whole thing yet My bad :-) they make ones like this for around $8 from china butthey do not work. I have yet to have one work well. so for now the DIY route is still the best route :-)
Op-Ivy says: Jun 20, 2010. 12:39 PM REPLY
Hi Honus, thanks for posting this DIY. It has inspired me to make a charger similar to this!
However I'm having a problem that I was hoping you could help me with. I want to make a very basic ipod charger that does not require batteries to use.Right now I have the solar panel connected to a 5v regulator and then directly to the ipod. It's a 5th gen nano and I have combined the D+ and D- wires onthe ipod cable but it will not charge! But when I hook up my cell phone to the solar charger it starts charging it!
The weird thing is that I can hook the the connection to a 5v source on my computer and it will start charging! So there must be something wrong with mycircuit.
Does the ipod require a certain milliamp rating to charge? The panel is rated at 150ma at 6V.
I'll be going backpacking for a week in the bush and I would love to get this working! Thanks again for the DIY Honus!
http://i96.photobucket.com/albums/l163/Op-Ivy/1-1.jpg
Honus says: Jun 20, 2010. 1:23 PM REPLYWhat do you mean by combined the data lines? iPods are pretty finicky about data line interaction so I suspect that may be the culprit. 150mA isn't muchcurrent- and I'm assuming that's if your solar panel is in direct sunlight. The MIntyBooost circuit can provide 400mA so at 150mA it would take a long timeto charge.
Op-Ivy says: Jun 20, 2010. 2:56 PM REPLY
The data lines have been connected to each other, basically making a loop from the ipod and back to the ipod. After doing some research on theinternet I found that the only way to get it to charge is by doing this. It proved correct after I connected the 5v line from my computer.
I'll try getting another solar panel and upping the amperage. Do you think the reason could be because of the low amperage? It's the only variablethat changes now from hooking it up to the 5v line and hooking it up to the solar panel.
Thanks for your help! :)
Honus says: Jun 20, 2010. 3:26 PM REPLYI haven't done anything like this so I honestly have no idea. Looping the data lines back to each other doesn't seem right to me though.
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