Solar Panel glass / 12 volt power "Spikes"

Submitted: Tuesday, Nov 01, 2005 at 19:39
ThreadID: 122305 Views:3997 Replies:3 FollowUps:1
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Now that we are in the storm season here in S/e Qld, I am wondering what I can do to protect my solar panels from hail damage. It is stored out in the open. I have thought about a cover like a tarp, but i would have to insert clear panels in the roof section for the solar to keep working, and what a headache to put it on and take it off. Does anyone know how thick the glass is on these solar panels, and also whether they are just ordinary glass, or the toughened variety like our car windows. If they are the toughened variety I will not worry too much about them, but if they are ordinary glass I feel i should make the effort and protect them somehow.
I have a small single LED light in the roof of the En-suite which self destructs after after about 50 hours service. They are not too expensive at $13 each, so I have been replacing them as they fail. I think they fail because of "Spikes" in the 12 volt power supply. I have mentioned this to Steve, and he agrees, and says they are not reccommended at this point in time, but research and development goes on.
I accept that, as it was my idea to put the light in the Loo and not Bt's suggestion.
Does anyone out there know if I can put a resistor and capacitor in the 12 volt line to that LED lamp to stop the "Spikes" from getting to the lamp. I am electrically challenged, so any reply would be appreciated in laymans language. Would this effect any of the other electrical systems?
Thanks in anticipation, Keith & Joan.
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Reply By: Bushtracker - Tuesday, Nov 01, 2005 at 21:11

Tuesday, Nov 01, 2005 at 21:11
Hello Keith and Joan, somewhere out there...

On the solar, I would not worry about hail.... My own van went through 1 1/2" hail, some 2" discs of hail, and not one of the four panels had a problem... Maybe of eight or ten hail jobs in ten years that we have done, only one had a panel shattered and that one did not look to be hail damaged... It might have been there for some time with a rock damage as the other panels on that van were fine... I would say we have only had about three shattered panels in ten years, out of thousands of panels, and not one really attributed to hail damage... So, do not worry, your odds are greater of being hit by lightening or eaten by a shark... Ha!

On the LEDs, there are many reasons that are being postulated as to why most brands are winking out in our application with solar and 240 volt chargers.. One early theory that was put forth was the "spikes" you are talking about... But another theory has taken over, in that they just do not like voltages over about 13 volts.... The multi-voltage units that run on 6 to 42 volts are having better results... So you might try them... But so far, about ten Companies that build the LEDs are scrambling trying to define the real answer, and the truth is that it probably varies from one to another... One susceptible to voltage spikes, one type sensitive to higher voltages, probably both are true... One theory put forth was even amperage surge, with equipment shutting off and on showing up in a flickering LED, but even that explanation might just be micro changes in voltage as the load goes off and on, and have nothing to do with amperage... So... No one knows... Even a fourth theory is the AC application LEDs vrs the DC application LEDs... In nine months of research, only one type has passed all the tests, only one we offer.... But there was a limited success in the 6-42 volt multi-voltage truck running lights models, and you might try them...

Regards from the Ranger at Bushtracker... Always trying to find a better trail...
"The Last Stand In Open Country"

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Reply By: Keith & Joan - Wednesday, Nov 02, 2005 at 06:03

Wednesday, Nov 02, 2005 at 06:03
Thanks Steve, you have put my mind at ease about the solar panel glass.

Regarding the LED light in the loo, I have been talking to my brother in the USA via email, & he reckons the correct resistor in the Positive line, and the correct Capacitor across the Pos and Neg lines just prior to the LED light should do the trick. I am going to purchase another replacement LED for the loo and give this idea a go. Nothing ventured nothing gained. If I take a reading of the volts at the LED, he will work out the correct values for me, then all I have to do is go buy them and connect them in the circuit. I will let you know what happens.
I thank you for your input to my questions, I realise your time is very limited to be answering such queries. Nobody could possibly fault the service from yourself and all the BT employees
Kind Regards, Keith & Joan.

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Reply By: Aussie Bush Ghost - Wednesday, Nov 02, 2005 at 23:11

Wednesday, Nov 02, 2005 at 23:11

We had BT install an LED just outside the ensuite door on the ceiling so it provides great light through the Perspex door for the loo in the middle of the night, and provides sufficient light to allow us to get to the loo door in the middle of the night in the otherwise pitch dark, without tripping over the dog etc.,

It has been burning nearly every night (and often in the day as well) for close to two years. (we leave it on while stored too)

The trick I used was to buy a hand held “bright LED” torch for $5 at Crazy Clarks… measure the voltage across the actual LED of the torch and then calculated & tested the value of the resistor necessary to drop the 12-14 volts of the van voltage to that across the actual LED in the torch (From memory I think it was 5.5volts).

I then fitted the LED & half watt resistor (plus a mini bridge rectifier to allow it to be connected to either the + or – of the supply) into a standard miniature (architrave) Clipsal twin switchplate blank & switchplate which looks quite neat and has a switch. I enclosed the rear end of the LED with resistor & rectifier in epoxy….. the whole thing is about 15mm x 15mm x 15mm & the LED protrudes out the switchplate blank by about 4 to 5 mm, thus the bulk of the whole epoxy and components is recessed & hidden by the switchplate.

All up cost was about $20.

Whilst I considered inserting a condenser (capacitor) across the line at the time, I did not include one as the battery’s should act as a large capacitor and should absorb any voltage spikes,
(I am pretty ignorant as far as solar cells are concerned so could be way off track here) althouigh I suggest or suspect that the problems that you are experiencing are either higher continuous voltage above the design performance specs of the LED light or it’s the quality of the LED,s

If you continue to have trouble I will pull ours out and check the value of the resistor & let you know. Be aware though that ours is a “raw” LED .. Ie there is no componentry at all built into the light other than the bridge rectifier & resistor.

Incidentally, while playing around with voltage onto the LED, I discovered that the LED would light up from less than 4 volts to 14.5 volts (may have been more but that’s all the voltage available to me at the time), and it stands to reason that the higher the voltage the shorter the life of the LED. The light output did not appear to increase significantly over 6 volts.

Hope this helps.

AnswerID: 567364

Follow Up By: Bushtracker - Thursday, Nov 03, 2005 at 01:03

Thursday, Nov 03, 2005 at 01:03
WOW ! What a lot of great tinkering for a Night Light...!!!

I would love to have an easy answer like that, or be able to buy one already like that.... My problem has been all along, that the LEDs came from a variety of sources, and had different tolerances... There were no constants... And each Manufacturer came up with a different and sometimes unbelievable explanation for the failures... Like "amperage fluctuations" (can't see that as relevant), or "voltage spikes coming through from the 240v charging" (can't see that one either as the battery bank is like a 100kg capacitor, plates operating the same way dampening any spikes)....

The technology is just a bit raw yet, and believe it or not we had batch variations as the Manufacturers obviously used LEDs from China that had different sources to make up into the lights that they manufactured... So one batch would be OK, and the next... Ooops!

We just have to wait until the LEDs get caught up with the various applications with protective circuitry on board, or a higher tolerance LED itself... Only one type of over a dozen so far, has proven invincible.... The Halogen replacement one we are installing now...

Kind Regards from the Ranger....
"The Last Stand In Open Country"

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