Solar Charger Using Salvaged Yard Light Solar Panels

[SkyWatcher]

Hi folks, just thought I would share my dirt cheap AA or AAA cell solar battery charger.
The yard light solar panels are all in parallel and I have a battery holder, that is wired all in parallel.
The plastic waterproof container was from a grocery store hot food item.
It also has a heavy piece of steel on the bottom, taped on using high strength packing tape and a angle piece of aluminum taped on also to give it an angle into the sun.
Also, the solar panels are taped on the inside using the high strength packing tape.
This is completely waterproof and wind proof, well at least for normal winds, not tornadoes, hehe.
It charges even off inside lights and I will be putting it outside tonight, to see how it charges some AA nimh in the sun light tomorrow.
Hope you like it.


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peace love light
tyson

[SkyWatcher]

Hi folks, The charger works fairly well I would say.
I placed two AA 2000mah nimh 1.2 volt rechargeable cells in parallel this morning and since it is an apartment, I probably got about 4 hours of good sunlight in the back of the building.
The two AA's read 1.03 volts before charging and when I took them in today, they were at 1.35 volts each.
I then load tested them with an led flashlight that I used the prior night to discharge with, It ran the light for an hour, where normally I get around 3 hours with these batteries fully charged.
So the two AA's charged to about 33% capacity in that roughly 4 hours time.
That seems pretty good to me, let me know what you folks think.
Also, I should say, that it seems like placing the solar panels in series to charge the AA's in series is not as efficient in charging as the parallel setup, not sure why that is as of yet.
peace love light
tyson

[SkyWatcher]

Sylcell Charging Method

Hi folks, I almost forgot about the 'Sylcell' charging method.
This patent explains why my parallel connected solar panels and parallel connected AA nimh cells, charge so much better than placing the panels in series and AA cells in series charging configuration.
Here is a quote from patent,

"The series-parallel connection of the PV cell array 18' and pool battery 10 lowers the effective internal resistance of the array, optimizes PV and battery impedance matching, and thereby substantially improves the efficiency of energy transfer to the battery cells."

or

The internal resistance of each of the charging sources is matched to the internal resistance of each battery cell. The configuration provides substantially faster charging of the battery cells than is possible using convential battery cell array charging configurations

In the article the data showed a solar panel that would normally take 6 hours to charge the battery takes less than 1 hour under the same solar conditions using the Sylcell charging method.
Here is a link to an article about sylcell.
Solar Cell Power Doubler - KeelyNet 12/17/01
U.S. patent 4,651,080


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I plan to test this method also, even though I am probably close to just as efficient with my parallel wiring configuration, though we will see.
This sylcell charging method is no joke, I used my 40 watt incandescent bulb inside as a light source and when trying to charge my two AA nimh 2000mah in series with my panels in series, the batteries barely rose in charging voltage at a constant distant from light bulb.
Then when the solar panels are wired in parallel and the AA cells charging in parallel, the batteries start to rise in voltage steadily, from the same distance from light bulb.
People should try this, this would be especially good for poor areas using solar power or people like me, trying to squeeze every ounce of charging efficiency from cheap yard light solar panels, hehe.
peace love light
tyson

[NickZ]

With SYLCELL, groups of battery cells are connected in series with each other to form a pool battery, and groups of PV cells are connected in series with each other within a PV array. The two groups are then interconnected in parallel to form SYLCELL. The series-parallel configuration provides maximum power transfer from the PV array to the storage battery.





Skywatcher:
I have connected 6 garden light solar panels together in series, to obtain about 12 to 14 volts, but with only about 30mAs of current. I plan to hook that solar array up to my Exciter circuit set-up. But, the current output from the solar cell array is not really enough to sustain the Exciter's needs, which is probably about 50 mA or higher, at 12v. The Exciter will also run from the cells direct, even indoors using a 13 watt CFL to provide light for the cells, but the indoor light only provides for 2 mAs, compared to 30mAs outside in natural sunlight.
I also have a 12v 4.5ah LAB to use with the solar panels. But, like I mentioned, the current given by the panel array is not really enough to charge the 12v battery. Or is it? I'm in the process of finding out.

Charging the batteries from your solar cell INSIDE the house using a 40 watt bulb, you'll find that although the voltage will be somewhat similar to what sunlight gives, the current output from the solar cells will be much less, like 1/4 of the current, or less. That is the reason that it won't work inside as well, using artificial light.

Right now I have the 6 solar cells connected in series, that are charging in full sunlight outside 4 AA rechargeable batteries. The 4 AAs are also connected in series as they are in a plastic 4 AA holder. The batteries are connected in parallel to the solar cells, like is suggested by Sylcell. The 4 AAs have already charged to their 1.250 voltage, only after a couple of hours sunlight, although they were not fully discharged to begin with. I'll test those same batteries tonight and drain them running some leds, to see how well the charge on them will hold up.

NickZ

[SkyWatcher]

Hi nick, thanks for the reply.
I used the indoor light bulb just as a reference to see what the difference is between wiring setups, so I will know if it will be better when placed outside in sun to charge.
I also notice that the sylcell patent mentions the fact, that there wiring setup is not the only way, I tried two of the small solar panels in series parallel with two AA cells just like sylcell method shows and it did not perform as well as just the solar panels in parallel with the Aa cells in parallel also.
So my guess is, is that the idea is to get the best impedance match between the solar panels and the rechargeable cells as possible, to get maximum charge transfer.
Also, not sure if it is realized, the patent shows 2 volt lead acid cells being used for 12 volts total, whereas typical solar systems use either 6 volt battery, comprised of 3 - 2 volt cells or a 12 volt battery, comprised of 6 - 2 volt cells.
Not sure how practical it is to obtain large capacity 2 volt lead acid cells, though that would be needed to maximize solar charge efficiency as stated in patent or article.
peace love light
tyson

[NickZ]

I'm still testing the 6 cell that I have in series. I'll need to completely drain whatever battery I'm using to know how well the cells will charge the battery.
I'm hoping that I can actually charge my 12 volt 4.5 ah lead acid battery from the 6 little solar cells. But, I'm not holding my breath. I know that I can charge smaller batteries with the cells, but the Exciter needs and wants the 12 volts to run its best.
If you haven't seen Hitmanmob1 video about using the 6 garden light cells to charge a 6 volt battery, and they he runs 10 2 watt led bulbs with that set up.

[SkyWatcher]

Hi nick, thanks for the reply.
Yes, i've seen that video you mention with the super joule ringer, though even his setup does not have great charge transfer efficiency and neither will your 12 volt 4.5ah, though free sun power, so we can't complain too much hey, hehe.
If you instead, take say, ten AA 2000mah 1.2volt nimh rechargeable cells and try the sylcell series parallel method, you should get much greater energy transferred from the solar panels into the AA cells.
Then you can try placing your solar panels all in parallel and also all 10 AA cells and see how much better the charging is.
10 AA in series at 2000mah is 24 watt/hours, so placing another 10 in parallel with that would give you the same 48 watt/hours or so that your 12 volt 4.5ah lead acid gives.
I figure that my 4 yard light solar panels are outputting around 200 milliamps into my 2 AA 2000mah nimh cells, since I can power an led flashlight at 2.7 volts, 430milliamps for an hour off of about 4 hours of sunlight.
The 12volt 4.5ah sla has too much resistance between cells to charge efficiently with those small yard light solar panels.
peace love light
tyson

[Blargus]

Cool! Let's see if my local solar panel installer is interested in that patent..^^

[Guruji]

Cheapest price SP

My Cheapest solar panel that I've did.

Very Cheap price Solar panel build - YouTube

[SkyWatcher]

Hi folks, Hi guruji, nice setup you have made there, does it have any clear cover material to protect from rain and have you used your home built solar panel using broken solar cells to charge a battery yet, thanks for sharing.
Also, how much were the broken solar cells shown in the homemade solar panel in the video, thanks.
peace love light
tyson

[SkyWatcher]

Hi folks, Thought I'd offer my observations with this solar charger.
As I suspected might happen, when charging multiple parallel AA cells, the cell with the lowest resistance will receive the most charging current and so this leaves the other cells with less charge.
So the solution, either use the sylcell (series/parallel) method or only charge one cell at a time and in my case, is ok, since the total output is only around 200 milliamps from these yard light solar panels.
Though another solution when charging parallel cells, might be to use a small value resistor for each AA, etc. cell that is used, to balance the charge distribution to each AA cell.
peace love light
tyson

[NickZ]

SW:
Thanks for your updates.
I've got my 6 solar cells out in the sun now, to see what they will do to charge the 12v battery.
I'm still intrigued by what Hitman has done, with the same number (6) solar cells, and able to light the 10 2watt bulbs, and also charge his laptop, all at the same time. This seam like something unreal, but there it is. What I'd like to know is how long will that set up maintain the 10 bulbs lit, as it's running 20 watts worth of bulbs, but possibly at only about 1/2 brightness. Still pretty neat though.
Yesterday I rewound a used E-core to connect a Ringer circuit to the 12 battery. So, we'll see how that goes. I would prefer to buy the RS transformer,
but will try first with some used 12v transformers that I have on hand, beforehand.

[SkyWatcher]

Hi nick, thanks for the reply.
If hitmans yard light solar panels are anything like mine, he is probably getting around 50 milliamps at 12 or so volts, that is if they are each 2 volt solar panels and if they are 2 volts, I'm not sure if his sla is charging much over 12 volts.
I am starting my single AA nimh cell test tomorrow to see if I can get a full charge in it, since before I was unable to with the two parallel AA setup, because I think one cell was taking most of the charge.
Also, after I perform more tests just using direct solar, like using the resistor per cell to balance the incoming charge from the paralleled solar panels, I want to try and run a joule ringer off the paralleled 2 volt or so output of the solar panels and use the flyback to try and charge paralleled AA cells.
We will see how it goes.
peace love light
tyson

[NickZ]

I did have some luck charging the 12v battery today, as the 6 cells raised it from 11v back to 12 in about 4 hours. I'm sure that it would charge a single rechargeable 9, or 6 volt battery just fine. The thing is to not let the battery drain down to far, so that it will charge back up easily.
Hitman mentioned that his 6 solar cells are 3 volts each, and he is charging a 6 volt battery to run all those 10 2watt lights. Mine are mostly 2volts, and 30 mA, but I have one cell that is a 4.3 volts, 30ma, all are in placed in series.
I need to get at least 2 more of those cells, to reach 18 volts, as I can get only 14 volts in full sun, but only 30mAs. I can run my Exciter even on 3/4 volt, but it needs some more amps to work well, a couple more cells placed in parallel would give me enough current, also.
Some of the garden lights are real junk, but the solar cells themselves are nice, and they don't wear out. Since it's all free I can't complain.

For those that have not seen Hitmans video, (he has several), here is the link:
SJT Powering 10 lights and charging a laptop - YouTube

This is my latest video, I'm still working on improving the Exciter circuit.
It is the same 12 volt circuit that the solar cells will run.
Simple Jt Exciter No, 2 - lighting CFL bulbs - YouTube

[SkyWatcher]

Hi nick, thanks for the information on his yard light solar panels and the video links.
I couldn't get much results on my single AA charging test, it was overcast, though I can tell it is charging nicely, hopefully I can get an actual full charge.
I wonder if the heat the AA nimh is exposed to is causing it to not charge completely, since the container I'm using is almost like a solar cooker, hehe.
Also, I checked the amperage output in full sunlight today with the 4 yard light solar panels and they are giving 240 milliamps.
Also, I made a joule thief using a salvage 1" toroid, i think its a regular iron one, not sure though, it has green paint.
I placed the AA across the collector and emitter (2n4403) using a diode to collect the continuous current and the flyback pulse, though the charging is a little slower, though maybe a better toroid would make it more equal to direct charging.
Maybe I'll try a small e-core next as a joule thief.
Reason I wanted to try the joule thief as a radiant charger using the 4 solar panels, is that I think it might give a better balanced charge to paralleled AA cells.
peace love light
tyson