Reviving a broken panel

[guruji]

Sir I am trying to revive a broken solar panel.I tried doing copper tape on cracks but still giving low voltage reading even I stunned wires from one side to the other still same thing.I cannot get the voltage it suppose to give 18v 5watts.

Any help would be very appreciated.

Thanks.

[Nando]

Cracks where, the glass or the Silicon wafers ?.

If the silicon wafers, you may short circuit those broken to close the electrical loop -- to save the broken wafers -- I may need to see them.

For each cell ( wafer ) that is short circuited about 0.6 volts are lost for ever.

Nando

[Mike Cross]

If the cells are broken and you are getting much lower open circuit voltage than the panel is rated, you have a broken or shorted circuit.  Trying to fix broken cells is like trying to glue an egg shell back to gether.  Even if you could string a connection over the breaks it would be a series circuit and voltage would be incorrect. You would have to mend the break in the cell, not bridge it with wire or tape.  

Having said that if you are still getting good open circuit voltage then proceed with the following.  It worked for me.

To my knowledge there is no way to separate the broken glass.  The cells are stuck to it by an adesive membrane.  This membrane is to keep dust and moisture out.

I have made five "sucessful" attempts so far in saving this type of damage.

This is what I have done:

First check the out put of the open circuit of the affected panel alone in full sun.

If voltage is the rated output proceeed.  If it is below the amount to charge a battery it should be replaced.

After removing panel from the frame and laying flat on a work bench so it doesen't fall and break more.  It is now very fragile.  Some of the cells maybe fractured. You don't want to break more.

WEAR GLOVES, EYE AND FACE PROTECTION AGAINST FLYING BITS OF GLASS!!!

vacuum (do not blow, the shattered shards will go everywhere like shrapnel) out the tiny glass and dust.

wipe clean with a lint free wipe and a quick evaporating solvent, like acetone, (available anywhere paint is sold)

Reseal panel. (do not just put glass or plastic over it. You will just trap moisture that will condense with cold, and air that will expand with heat and break your repair.

 I have two methods of resealing the panel:

 First method: using  "Scotch Brand"  "package storage tape".  It seems to take the heat and the cold and remain clear.  (Do not use ordinary package tape it will come off after being in the weather and heat.}  Seal over the broken glass.  Then using "Liquid Nails Clear Silicone Sealer" it says on the tube:  "will not yellow" "will remain clear and flexalble for 50 years".  This is the only commonly available silcone sealer that says that.  I found all of these products in the paint and also in the stationary departments at Walmart.

Use the following proceedures:

In Shingle like fashsion layer the tape across the shortest dimension of the panel. If you go the longest demension it is hard to keep straight.  Then seal only the edges where the tape meets the frame.

Second method: Just carefully smooth on the Liquid Nails Silicone Sealer with a  

2 inch wide putty knife all over the broken glass as thin as possible with out leaving any open spaces. Don't use the tape.  Let dry in a horizontal position  in a clean dust free enviorment over night.

Again check output voltage.  If it is just a little lower due to the covering you have put over it ok. Should not be more than a half a volt difference. However you need to check it because a cell could have broken just by handling.

The tape method turns out clearer, looks better, easier to keep and is harder to do.  The silicone only method is easier, stronger, but is translucent.

I was able to save 5 out of eight panels.  2 of the panels had no voltage. They had holes right through the panel.  1 one of the panels had only six volts.  I am saving these for future experiments.

No promises, but if you can save an expensive panel for a few bucks it is better than discarding them to the trash.

Good luck

[guruji]

Thanks guys for the info.My solar panel is not a cell it's a 13inch by 13inch panel.I did that copper tape but still giving 7v.Maybe I have to clean it with that solvent that you mentioned Mike.

Ok anyway thanks for help.

[Clifford]

(sorry, some of this is from more theory than actual wiring experience.  Still working on making a panel myself, as well as trying to figure what the heck is wrong with my Siemens Panels.  And, of course, I am always willing to put my foot in my mouth).

Assuming you are talking silicone based cells, you should have something like 30+ individual cells, each putting out approx 1/2 volt.

I think the voltage is a rather resilient feature of the solar panels...

I.E.  If you have a fragment of a cell, it will put out the same 1/2 volt that the other intact cells put out.

The fragment of a cell, however, will put out fewer amps than an intact cell.

If you put the fragment of a cell in series with intact cells, you should have relatively good voltage, but the amps of the entire panel will be depressed (based on the lowest common amperage in the series).

Many cells have two wires along the top.  However, this is just to confuse you (I think).

I believe that the individual cells are connected as follows:

(terminated) Top -> bottom (terminated)

(terminated) Top -> bottom (terminated)

(terminated) Top -> bottom (terminated)

I.E.  Any single conductor only goes from the top of Cell A to the bottom of Cell B (and nowhere else).

After you string everything together, the potential of the entire panel is measured from the top of the first cell to the bottom of the last cell.

Two fragments could potentially be connected in parallel...  

(Top Fragment A -> Top Fragment B)   AND (Bottom Fragment A -> Bottom Fragment B)

So...  look at your output.  This is more or less what I would expect:

Normal Volts - Normal Amps   -  This is what you want.

Low Volts - High Amps - Somewhere (near middle) you have parallel rather than serial circuit.

Low Volts - Normal Amps - Skipping cells, or parallel with fragmented cells.

Low Volts - Low Amps    - Skipping Cells in the circuit (and or fragments).

No Volts - No Amps        - Somewhere Disconnected  

Good Luck,

P.S.  You can certainly cut down on your power output if you significantly obscure all of the cells such as using Low-E glass, using the panel inside the house, or something similar.

[guruji]

Thanks Clifford I jointed with wire that what I found best cause the crack was diagonal.At least it's giving 11v.

Can I connect this in series with other cells so that they give me around 22v in all.Is this voltage good to charge batteries?.

Thanks again.

[Mike Cross]

Back in June 6/16/06 I stated that cracked glass photovoltaic could be repaired by using Liquid Nails Silicone Sealer.  I also stated that it was guarenteed for 50 years.  

I can no longer make that statement.  I appologise if anyone followed my instructions.

I had used Liquid Nails Silicon Sealer on 3 Siemans  panels with cracked glass.  Part of May, all  of June, July, the panels worked fine. But by the second week of August the Silicone Sealer was  turning Yellow and Milky.  

I phoned the 800 number on the tube of sealer.  After some conversation on how and were their product was used Liquid Nails agreed their product did not work as required.  Today I receive a full refund for all 12 tubes of Liquid Nails Clear Silicone Sealer.  I had really wanted that to work.

I was able to remove the Silicone Sealer with a razor blade scraper.

I have since  called 5 different divisions of 3M corporations seeking a clear plastic laminate for photovoltaic panels. The two possiblities are: 3M Clear Storage Tape which I am still using on two panels and have added to the panels that had the Silicone Sealer and 3M window security laminate film.  However I have not yet tried the security laminate film.  Security laminate film is hard to find, has a UV inhibtor in the adhesive, and is only warrented for indoor use. Therefore 3M has stated it probably won't work.

I think a properly designed plastic laminate made from a polycarbonate, (like the type used in soda bottles) would work if it could be found.