The solar cells have arrived!

[iFred]

The solar cells have arrived! Now to see what kind of shape they are in... I ment the cells.. what where you thinkin?...LOL

[tecker]

 Nice hat .Are you taking applications for a temporary position .

[monte350c]

Good one Fred! (I might have to switch from purolator)

Seriously though, what kind of shape did you find the cells? ie how many will be usable?

Am ready to order some too, I've been following your progress and look forward to some relatively inexpensive solar too.

Ted.

[iFred]

So here are the stats, 36- opps.. wrong stats...

The cells are all in what looks to be EXCELENT CONDITION!!! A bonus!

None are broken in the 3 pounds that I have purchased first. This is the first shipment.. I have another 10 pounds coming..

I got about 50-60 cells per pound it looks like. They are EXTREEMLY WELL PACKAGED. 3 layers of bubble wrap, double boxed and extra card board, and more bubble wrap. Plus they are also wrapped in Brawnee wrap. All in all Excelent packaging.

The cells where listed as seconds on the package and on the ebay site.. What does this mean? Exactly what it says. The cells either have some very light cosmetic issues such as slight glass folding (during the manufacturing process)-Looks like a paint is applyied that is not exactly level, its like highs and lows, but so small that you can't even feel it..You can see it however. (which would not effect the cell performance), corners that are very very slightly chipped, again - based upon the damage of the cell we are talking no effect the cell performance.. Basically the cells did not pass quality assurance for 100%. But I would say they are about 95-97 % good.

The photos do no justice to how pretty and COOL they really look. A very deep deep purple/light blue color. Very high light reflectivity.  

What appears to be the main problem with these cells is that the ribbon connections as shown in the photo (ignore the blemish and the dirt on my scanner- this cell is perfect) are coming off and need to be resoldered. This is almost the case on every cell received. This is also a minor issue if you are good at soldering.

The cells are EXTREEMLY THIN!!!!! They are like a sheet of paper and fragile. They will break under any strain. This was something I didn't expect.

As for connections: it looks like the front connections are for the actual cell and a rear connection needs to be soldered somewhere on the back of the cell.

If you are going to buy these cells, BE REALLY GOOD AT SOLDERING!!! I would say every cell is going to need it, and that means low temps, excellent silver solder and good technique.

All in all - A GREAT DEAL- BUY IT!!

For Canada Readers- I paid $40 shipping (this was exceptionally high-do not know why- the shipping bill says they only paid $22.15 for the shipping- so know that we are getting ripped on that one)  I estimate that I will get another bill yet for duty, gst & pst. Still if you estimate it out, it would come out to about $2 to $3 per cell. Not bad except for the shipping costs.

[iFred]

BAD CELL REPORT

Cracked corners

offset or misaligned wave soldering when wire was applied

Another broken corner area

discoloration or blemish, I have inversed negative of the picture to show it. What your not seeing is that the deep purple/blue color in this region is complexly missing. The cell is missing an area.

[iFred]

The cells come wrapped 15 cells in a single package. There are 4 of these packages in a pound = 60 cells per pound exactly. If you buy them per pound it will cost you $45 per pound, however the better deal is to buy 5 pounds at $35 per pound and save your selves $10. per pound!

Calculating for a panel....

36 cells are needed to make 13.8 volts for charging a battery . Actually this comes out to 18volts for compensation with a drop to 13vdc and be assured of charging.

-----------------------------------------------------------------------------------------

THIS DATA IS FROM THE EBAY SITE.

Here is the data on them (per whole cell, under standard test conditions of 100 mW/sq cm):

*    Peak Power--1.36 Watts

*    Current (max power)--3.02 amps

*    Voltage (max power) .45 V

*    Open Circuit Volts--.55 volts

*    Short Circuit Current--3.6 amps

*    these are about 50 cells per pound (or ~68 watts/lb)

------------------------------------------------------------------------------------

At 36 cells it should give about 48watts per panel on a good day, but I like to estimate for a little less rather then more so for the sake of argument say about 38 watts per panel with 36 cells. This will give 18vdc at 3 amps per panel. Check my numbers please!

[ibedonc]

you mite have higher losses with the 10 lb shippment , I order 10 lb and fedex lost 5 lbs of them and Bryon said that Fedex will in ins fragiles for more then $100

and if they loose them and refuse the claim you are out because Bryon will not cover them , in my case he told me it may take 30 days , but I just got a message that they

paided and he will be send me another 5lbs

anyway when he ships 5 lbs he stacks them higher in the box which broke a lot of the ones on the bottom of the stacks in one stack almost 1/4 lb was broke , I told him about that , he will not replace any that are broken because of shipping

in the 2 lbs I first got none were broke because of shipping just like you

[Barnac]

Thanks Fred for this informative tread. I was thinking of buying some myself.

I did put this tread on my hotlist and will follow your progress if you have the desire to continue to post about that project. I wonder on the ease of soldering back the connections together.

I appreciate the time you spend giving us that information.

By the way from now on UPS is the only delivery company that will be delivering at my place.

Regards

[iFred]

I put a single cell up to a 25 watt light bulb within 1 inch. I got .500 or ½ volt DC. No problems here.  I then connected the cell to my Amp meter, same test gave me only .400 ma or ½ amp. But it does show that the cells are working...

Resoldering Report

Major Problem in  resoldering the connections back onto the cell. First off it looks like the presolder that is normally put on all connections on cells comes off with the wire that is on their,  This seems at first glance to suggest that what is left is the back part of the cell or non-solderable area. what you are left with then is to solder directly to each of the lengthwise connection points, even this was difficult for me, and I am a expert at soldering.

This will be a problem... If anyone has done this before, please tell how you finally worked out the issue of soldering on the cells.

Thanks!

[iFred]

AH HA! I got it! To resolder these you have to first apply solder "at hi heat" to where the bus bar was and basically tin it first, then laydown the bus wire and resolder, it does work but the heat bothers me. Is discolors the cell. A friend suggested maybe using a chemical tinning agent that would pre tin the cell to make it easyer to solder the bus wire to. This would also help reduce the heat. The solar cell seems to act as a large heat sink as well when attempting to solder to it.

ANY IDEA'S OR SUGESTIONs??  

[ghurd]

Maybe its too obvious...

Have you tried a 20w iron with a drop of solder on it all ready?

A quick touch will deposite the solder without much heat transfer to the area.

Clean the iron, add the solder, touch the spot, all done quickly. I had concern about no flux, but it always seems to work, no failures to speak of.

It wasn't for PV cells, but other heat sensitive things, often held between the fingers. Yes, you can tell if it got too hot if you drop it.

Worth a try?

Good luck and keep us posted.

G-

[phil b]

I got my cells in last week from the same place. 172 are usable out of 5 lbs. At 60 cells per pound, I'd say the Fedup gorillas had a ball!

Anyway, I made a panel out of chipped and broken ones first since they ARE so fragile. If the main buss is intact even though the cell is cracked in half and dangling, they will still generate power. amazing! In full sun, 15 cells produced 7.2 volts in series. 2 panels in series = one 12 volt panel, I think.

Should I add more cells in series to get a higher voltage to compensate for future cell degredation or in parallel for more amps? My batteries are 30 feet away from the panels.

Thanks,

phil b

[ghurd]

Hi Phil,

You need more cells!

V open is no current flowing. It drops like a rock as soon as current flows.

You want to get to about 20 or 22 volts open circuit. Most factories use 36 cells in series for a "12 Volt" panel. If you don't get to 20-ish volts open circuit you wont do any charging if its overcast, have a shaded cell, or otherwise not a perfectly perfect solar situation. (add a blocking diode or controller and wire losses and 14.4vopen is not enough to do much good with perfect sun)

Degradation is not much of a concern in this type of cell. Try to get the panel sealed well, an on going discussion here...

Chipped corners and edges shouldn't have much effect.

G-

[tecker]

   Well Fred the ones I got arrived fed ex what's up with that . I 've been testing for about three weeks now and it has been a mess .I've been using a circuit pen to connect the open areas with some success also the fragile cells have been set aside and I'm repairing  with conductive epoxy . They aren't thick enough to really use a solder station . using that kestor silver solder mix and a hot air jet  .I 's fun and have a mosaic planed . I bought a 1 lb order and they were all usable low amps on 8 , 3 were repaired . I tested 80 in the 5 lb lot and 35 are good to go and 30 have been give a repair job and 20 under the magnifying glass yet to be checked further

[mikeptag]

What about just using Silver Conductive Epoxy instead of soder?

[mikeptag]

What about just using Silver Conductive Epoxy instead of soder?

[iFred]

Over the next couple weeks or so, I am going to figure out the best method of connecting these cells together. Bear with me on this, I'll keep you updated. I'll be trying low temperature solder, epoxy's, preheating the cell, tinning chemically ect.. to see what works best to connect these cells together. I'm also going to make contact with the manufacture and find out exactly what materials they use to create the interconnection bus lines and what will work best to connect to them.

In the mean time, if anyone has any data on these cells or knows the manufacture could you please post the data. Thanks!

Good Luck!

[bob golding]

ifred, i got some of the round cells from plastecs. i think they ae the same. i found using a 80 watt iron and putting 4 or 5 blobs of solder on the cell first worked ok. i fixed one end of the ribbon and run the iron down the cell, tedious but it seemed to work. when i tried it with my  smaller iron i couldnt get enought heat into the ribbon. look up sunrayce for more info. yes they are fragile arent they?

bob

[mikeptag]

I found this web page:

http://simon.baymoo.org/universe/ee/solar/amorphous.html

Quote:

When the first panel arrived, I had no idea how to hook it up. After doing some researching and asking around, I found that you have to attach wires to the silvery surface on the back. This can't be done unless you have conductive tape or conductive epoxy. Soldering just doesn't work.

At first, having no epoxy, I chose conductive tape. I've found that aluminum tape from a hardware store works just fine. (If possible, take an ohmmeter with you to test things out). However, I began to fear that the tape might eventually pull the backing off the panel and ruin it. So I switched to conductive epoxy

[mikeptag]

Just do a google search like this:

"solar panel" "conductive epoxy"

Theres a lot of links like this comment board:

http://www.allelectronics.com/cgi-bin/category.cgi?item=SPL-960&type=store&review=all

Seems a lot of references to epoxy and giving up on or not recommending sodering.

I wonder how the conductive epoxy would hold up with heat and cold and sunlight over time though. I'd hope the epoxy manufature has data.

I got some used panels 10 years ago, they were assembled except I had to seal the sides to keep the mosture out. I had to use a special sylicone that was made to hold up to years of sunlight. I found it good to add more over time to keep the seal up. Its the trickiest, like double pane windows, mosture finds a way in.

Mike

[Reno]

Hey Fred

it's called brokerage fees(what UPS wants for doing the paperwork to cross the border. Always try to have stuff shipped by US mail they deal with canada post and no brokerage fees but packages have to be small.

[iFred]

I contacted Byron via email, he in turn contacted a freind. THis is the reply I recieved.

> The material in the back is fired on silver. I think the front is the

> same, but am not entirely sure. The mfg of course won't say, as it is part

> of their proprietary process. I have soldered ribbon to the front with

> normal 63/37 electronic solder without much problem. The main secret is to

> not let it stay hot for very long, as the silver is thin and dissolves in

> the solder. If you keep it hot too long, and it all dissolves, then there

> is nothing to solder to except the silicon base, which the solder won't

> stick to

> . You can also use silver filled epoxy if you like. There was someone in

> AZ selling small tubes of it on ebay a while ago. I have never used the

> copper or carbon filled epoxy, but I suspect it wouldn't hold up so well

> on a hot roof after a while. Solder is the best, if you can get your

> technique figured out.

Also the cells are single crystal silicon cells, grown by a ribbon drawing process, pioneered by Mobil Solar. This is different stuff from the links above.

I need a data sheet on the cells for the chemical propertys to tackle it properly. but I think as Byrons freind suggested it's going to be some weird proprietary stuff.

Will See and keep you informed of the progress.

Good Luck!

[iFred]

Really frustrated, but getting it..

THERE ARE only two companies in and around Foxboro Ma from where Bryon lives where these cells are coming from. I figure it's gotta be close to his address or business so... I tracked it down with map quest, within a 50 km radius. Wana take a poke at which corp made them??

http://www.spirecorp.com/Spire/contact.html

and of course you might have guessed it already...

http://www.evergreensolar.com/

So, the next question is, which one uses ribbon technology to make cells...

Again... there is only one company that is within reach, and that would be everygreen, they are also the innovators of the ribbon drawing process. My bet is that these solar cells come from evergreen solar.

[iFred]

I just love coincidences...

String Ribbon's inventor, Prof. Emanuel Sachs. Worked for Mobile solar, moved to and created Evergreen Solar Corp along with other Mobil solar scientists.

Bryon says they won't talk about it because it is proprietary technology. Well Evergreen say on their web site the same thing...

Evergreens cells are 6x3 standard size..same size as the cells we have..

http://www.evergreensolar.com/egsolar1/eg_products.htm

They look the same.. But there is more.. if you download the PDF files from the site and review, you will see the amps and volts and number of cells needed are identical output to what we are dealing with.. Any one wana place bets???

These Solar cells are from Evergreen Solar... Gota ya!

[iFred]

IF at first you do not succeed, then go about it another way, cause your doing something wrong.... Here is the indirect way! ENJOY GUYS! How they made the cell contacts... with a machine..

Clickity click click click!!

http://www.assemblymag.com/CDA/ArticleInformation/coverstory/BNPCoverStoryItem/0,6490,121366,00.html

Bingo!!

[tecker]

   Here's an ok soarce for the conductive ink and epoxy I have been putting a coat of clear poly in the new traces and epoxy .

[tecker]

 that's on the traces

http://www.web-tronics.com/printed-circuit-board-supplies-circuit-board-aids.html

[RatOmeter]

Great sleuthing, Fred.

So I guess we can't apply the silver like they do, so the options are careful soldering or conductive epoxy?

I think I read somewhere that the cond. epoxy's main drawback is higher resistivity leading to voltage drops.  Not sure on that, though.

[Joel]

I've been following this discussion with great interest as I have #2 due to arrive shortly.  Out of curiosity, has anyone tried the toaster oven trick that some use for SMD components?  Depending on what type of solder you use the oven should get hot enough to reflow.  Here's a link to a table of solder and their respective melting points: http://www.ensil.com/international/Database/DB-Electronics/DElec-Solder%20Melt.html