Instructables

Tim's 5W Solar Charge,12VDC 4.5AH Portable Power Supply.

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This Project is primarily design for charging communication equipment & gadgets like Laptops,Hand phones, GPS, LED lights while doing mission work in remote area without Grid Electricity Supply.
The capacity of the Power Supply is sized for above personal equipment with portability,availability of material,cost effectiveness & flexibility in mind. 5 Watts Solar panel pumping out 17 Volts was targeted so as not to overcharge Internal 4.5 AH Lithium Ions batteries with only blocking diodes to maintain Simplicity.
From the desk of :
Timothy Wooi ,
20C, Taman Bahagia,
06000, Jitra, Kedah,
Malaysia.
email:timothywooi2@gmail.com
http://facebook.com/timothywooi
 

Awesome idea. I am going attempt to build the project. I have some a123 batteries laying around from old VPX packs. Wonder if I could use these..here are the specs...

http://www.elektromodely.sk/A123/APR18650M1_2007-05.pdf
splazem2 years ago
Very cool!
far play but i have made a laptop that powers and charges its self ave had it on for about 3 days and the unit you have is big once the unit i have is finished it will be smaller than a laptop charger but good jop
Very nice project!!!
sunal1353 years ago
I believe it is only a matter of time before your batteries go up in flames; yes the diode is all you need to charge but what about over charging; also i believe you wouldn't get the necessary amp out of the device to charge and discharge at the same time; if you regularly monitor the heat of the battery with your hand, that would work, but you should add a switch in for charging and discharging.
Timothy Wooi (author)  sunal1353 years ago
Well no one can change what you beleive,but Ive been using this set up almost half a year without any problems and will stick to this set up.Engineering is such that Input & output once match with a little 10% tolerance is ok & I dont need a switch to intentionally waste Energy to discharge it.I have a 9 units LED lamp again design to discharge the fully charge batteries over a time of 8 hours usage.I normally connect the lamp up to get light at night at the same time discharge it. Lean Thinking is all about not reinventing the Wheel.
.
The chances of it blowing are low. But its like how you should use an ESD strap when woring on electronics. The probability are slim to none.

I would like to see your cuircit to. The charging cuircuit I use is a slew of 2 op amps and 3 transisters
Timothy Wooi (author)  sunal1353 years ago
Since there are request for a circuit for this KISS(Keep it Stupid & Simple) project ,meeting 90% of my needs, Ive added a 15 V Regulator circuit for you all to use as a Constant 14.3V Charger.
Please bear in mind that incoperation of this Circuit will lower Charging Efficiency as for the Panels to charge, you need more than 15V to biase the Regulator. Below that threshold, it will not conduct thus Charge.
As for me ,I personally do not us it as mine charges as long as I have more than 13.5 Volts at Panels giving 12.7 V at Batteries terminals.
( as the Diode drop off another 0.7Volts)
Lean is all about using minimum resourses to add value to meet your requirement tapping on law of Nature & Equilibrium to acheive that Goal
All you would have to do is use protected batteries. You can also buy the circuit for $1.25 per batt. Saves a whole lot of worry and has hi and low protection so you don't drain them too far. Drain them too far and you just made a very expensive paper weight.
thalass3 years ago
If you ad some kind of hand-wound dynamo for cloudy days you'd have a perfect device! Or perhaps an auxiliary power input, for a variety of sources.

Great project!
Timothy Wooi (author)  thalass3 years ago
Tks buddy,Yes you do that or even add a 12 V dynamo with collapsible 36" PVC blades on top of a retractable Fishing rod to tap on Wind Energy (if there is)
I was thinking the aux input could let you do something like that, but still keep the handy portable charger.
ironsmiter3 years ago
cant wait to see your charge circuit... probably the most important part of a build like this.
Timothy Wooi (author)  ironsmiter3 years ago
Since there are request for a circuit for this KISS(Keep it Stupid & Simple) project ,meeting 90% of my needs, Ive added a 15 V Regulator circuit for you all to use as a Constant 14.3V Charger.
Please bear in mind that incoperation of this Circuit will lower Charging Efficiency as for the Panels to charge, you need more than 15V to biase the Regulator. Below that threshold, it will not conduct thus Charge.
As for me ,I personally do not us it as mine charges as long as I have more than 13.5 Volts at Panels giving 12.7 V at Batteries terminals.
( as the Diode drop off another 0.7Volts)
Lean is all about using minimum resourses to add value to meet your requirement tapping on law of Nature & Equilibrium to acheive that Goal.
Timothy Wooi (author)  ironsmiter3 years ago
Theres no circuit except for 1 Blocking Diode IN 4001 in series to the positivevs
That's a highly dangerous way to charge lithium-ion batteries. (e.g. no overvoltage protection at all.)

Li-Ions are supposed to be charged only with a current-limited constant voltage source - a solar panel with a blocking diode and nothing else is anything but that. Such a simple charging mechanism will result in either dangerous overvoltage/overcharging of the batteries, or if the blocking diode always keeps the battery below maximum charge voltage, significant undercharging of the batteries.
'Supposed to' is a bit misleading. 'Best' is probably a better word. They will charge like this just fine. But as I said before,
All you would have to do is use protected batteries. You can also buy the circuit for $1.25 per batt. Saves a whole lot of worry and has hi and low protection so you don't drain them too far. Drain them too far and you just made a very expensive paper weight.
Timothy Wooi (author)  Entropy5123 years ago
You are right as overcharging lithium ions batteries are dangerous but te batteries ,panels, min/max charging voltages cum current for a 7 hr exposure at extremes had beed evaluatee and match to preent such,thus this simplicity.Im fine with this set up & had been usint it for months enjoying it without any fear/problems or hazard to bother me.
Judging by the low output of these panels, I can't personally see overcharging to be a problem and think that the more bits and pieces that you put in between the panels and your device, the more power will be lost along the way.

I like this idea!

Windy
I like this. The fact it was born out of necessity and not a whim and that it is simplistic and practical are awesome.
Timothy Wooi (author)  TheAZAndyman3 years ago
Tq so much for your Lean approach in appreciating stuffs that are just Simple,Lean & Practical using minimum components & designed to tap into Equilibrium to minimise add ons automation -Pokayoke!
i would add some kind of breakout for the battery. perhaps a removable panel with a tether wire? I agree the compact case is a neat idea, but sunlight carries heat, and that is bad for batteries' charge level.
samhell443 years ago
how mutch volts/Ma are those solar panel ?
Timothy Wooi (author)  samhell443 years ago
13.5Volts typical at 120mA .
Maximum sun shown about 16volts but after putting a blocking diode IN4001 it dropped by 0.7volts bringing it over an average of about 13-15Volts on a hot sun. I used 4 cells in parallel to get about 480mA's which is just nice to full charge my 4.5AH Lithium Ion cells over 7 hrs of Sun.No electronics involved as I strongly believe in simplicity in design with minimum components for minimum breakdown.! Facebook.com/ Timothy Wooi or Tim's Waterfuel
iam gething 4 panels at 4.5v/80am whit 12 1.2 nimh 3000ma battery i think its gona do for what i need and ty for the reply
Timothy Wooi (author)  samhell443 years ago
Use 3 panels in series & thatwil give you 13.5 V typical. connect a diode IN4001 in seriesto the positive of the panel befoe connecting to the batteries.
Use only 10 units of the 1.2V Nihm,that will give you 12volts.
This is the siplest way you can Suncharge your 3000mA Batteries for a 12V battery pack.
You will need about 38 hrs of sun Exposure to full charge the 3000mA Capacity Batteries.Thats about 5 days! asumming Sunlight is about 7hrs per day.! day charge will give you about 20% charge on the Batteries. Tim
should i just get a 12v solar pannel whit more ma cos 38 is long lol
Timothy Wooi (author)  samhell443 years ago
For the size of your batteries it would be wiser to get a Solar Panel designed to charge 12V cells with a total output of about 400-450mA total so that a 7hr Sun will give your cells full charge without overcharging it keeping components to a minimum of just using blocking diodes!
Newegg just had a sale on 1.25watt 12v solar chargers for $9. I got the last two. I'm planning on using them to remotely power a wireless camera. Well not remotely, off grid. The plan is to use the solar panel to power the camera and use the rest of the power to charge the battery so the camera works after dark.
The camera needs 50ma. The solar panel is 125ma, so for about 7-9 hours the batteries will be charged at 50 - 75ma. They will eventually drain so I have to either give them more juice or turn off the camera like once a week. But it's an experiment.
Make sure you don't mix old and new batteries. Definitely not different brands. You may have batts that charge up a lot sooner than others, so they will over charge and burst or at least shorten their lifespan. When that happens it can damage the other batteries in your arrary.
luvasu3 years ago
Better use a simple non-expensive regulator. You can see mine at

***http://fadisel.es/solar-fadisol/reguladores-solares/reguladores-de-carga-de-baterias-fadisol-c-0190_R_366_1327.aspx*** fits inside the grey conexions box

(sorry Spain page) 25.70 Euros(= $37). Picture shows (nearly half-done) my system 1.5v each cell (12 plus 12 cells = 17v & 0.6 Amps) designed to charge batteries as the one you use. (12v 7Ah). with a single diode 1N4007 to protect the regulator.
All working 100% tested all over two years. (Why I do not have more pictures?)

3-MEDIO_PANEL-2.JPG
Timothy Wooi (author) 3 years ago
http://www.facebook.com/album.php?aid=2105801&id=1157253986&l=661db30ba8
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