Author Topic: My new 18w eBay solar panel  (Read 3212 times)

0 Members and 1 Guest are viewing this topic.

AbyssUnderground

  • Sr. Member
  • ****
  • Posts: 461
My new 18w eBay solar panel
« on: September 20, 2006, 12:58:57 PM »
I just got my new 18w solar panel from eBay. It looks really nice, metal frame and everything. I set it up and away it went... but for 5 minutes. Then the current cut out completely. I couldn't beleive it. The panel was broken. I spent 2 hours trying to find what was wrong with it. I narrowed the problem down to the connection block that connects the panels to the wires it comes with. I ripped it apart and there it was. A wire loose. The positive wire wasnt soldered to the metal strip correctly. Out came the soldering iron and it was fixed within a few minutes.


Unfortunately I also had to use a smaller piece of wire to connect to the metal strip. This is because there was so little of the metal strip to solder to, only a small wire would be small enough to connect to it. Now I have a fragile soldered connection and an open connection box. The solution? A yoghurt pot, some cardboard and lots of sticky tape! I made a sort of "box" around the fragile connection to avoid it being knocked and it snapping off. No picture of that unfortunately.


I hope it stays working from now on since if that connection breaks its probably going to be a useless panel. Fingers crossed it never has to be touched.


So whats the current like?


Excellent! In overcast conditions my entire array (24w) puts out about 0.5A. Ive seen 1.5A top so far but my analog meter only goes up to 1A so I had to disconnect my digital meter and use that instead.






My total array size is now 24 watts at 12v. You can see more details on the website in my profile.


All comments welcome :-)

« Last Edit: September 20, 2006, 12:58:57 PM by (unknown) »

Titantornado

  • Sr. Member
  • ****
  • Posts: 290
  • Country: us
Re: My new 18w eBay solar panel
« Reply #1 on: September 20, 2006, 07:22:46 AM »
Way to go, getting it to work.  Hope you won it for a great price.  I just got lucky on Ebay for a used 50w poly-crystaline for $5.07/watt shipped. (quite the feat when considering others are selling <50w panels for 9 to 15 dollars per watt!)


I might suggest applying a semi-flexible epoxy over your repair to encapsulate and protect the connection.  

« Last Edit: September 20, 2006, 07:22:46 AM by Titantornado »

AbyssUnderground

  • Sr. Member
  • ****
  • Posts: 461
Re: My new 18w eBay solar panel
« Reply #2 on: September 20, 2006, 07:27:00 AM »
Thanks for the reply. It cost me £70 ($140) buy it now including shipping. Not the best of deals but it was the best one I could find. Well, credit goes to Fungus who gave me the link some time back. The seller seems to have lots of these panels.


I think Ill leave it how it is for now. If it ever needs repairing again Ill definately make it a lot better and more permanent and use something to cover it, like epoxy as you mentioned.

« Last Edit: September 20, 2006, 07:27:00 AM by AbyssUnderground »

DANO

  • Newbie
  • *
  • Posts: 26
Re: My new 18w eBay solar panel
« Reply #3 on: September 20, 2006, 09:37:17 AM »
Hey there, looks nice and under $8/watt...checked your site too and the pics are rather informative.  When mounted on the shed roof, how long is the run and what size wire are you using....any fuses?  Later, DANO.
« Last Edit: September 20, 2006, 09:37:17 AM by DANO »

AbyssUnderground

  • Sr. Member
  • ****
  • Posts: 461
Re: My new 18w eBay solar panel
« Reply #4 on: September 20, 2006, 09:48:11 AM »
Its about a 10m run and its quite thin speaker cable, but it can handle 3 Amps easily. No fuses, just a diode in the charge controller at present. I see no need for a fuse on panels so small.


Thanks for the comment on my site. Always welcome :-)

« Last Edit: September 20, 2006, 09:48:11 AM by AbyssUnderground »

dinges

  • Hero Member
  • *****
  • Posts: 1294
  • Country: nl
Re: My new 18w eBay solar panel
« Reply #5 on: September 20, 2006, 12:34:59 PM »
For what current do you see the need for a fuse?


I can burn down your house with 100mA of current. Probably with less too. Just give me a 9V battery and a little incandescent lamp.


What do you think happens when the wires get damaged somewhere and short out? Lead acid batteries can make that wire light up light a lamp.


Sorry if this sounds a bit negative. But I get a bit annoyed when people save on a 0.10$ fuse. Call me cranky.

« Last Edit: September 20, 2006, 12:34:59 PM by dinges »
“Research is what I'm doing when I don't know what I'm doing.” (W. von Braun)

AbyssUnderground

  • Sr. Member
  • ****
  • Posts: 461
Re: My new 18w eBay solar panel
« Reply #6 on: September 20, 2006, 12:42:07 PM »
There is a diode in place so even if the solar side shorted out it wouldnt do anything, infact I often short it out to check the short circuit current.


The wire will melt, yes, but once its melted there is no connection so no more shorting out.


However, I will be investing in a fuse soon. It will go inside the monitor box. Its not me that wants it there, its my Dad.

« Last Edit: September 20, 2006, 12:42:07 PM by AbyssUnderground »

dinges

  • Hero Member
  • *****
  • Posts: 1294
  • Country: nl
Re: My new 18w eBay solar panel
« Reply #7 on: September 20, 2006, 01:12:01 PM »
You're missing my point: there's no lower limit on current that can cause fire. In fact, after I wrote the previous message, I realized all it would take was 20mA, not 100mA.


Diodes can malfunction too. A shorted diode (I've seen a few of those) act just like a piece of wire. Still sure you don't need a fuse?


I wasn't saying the wire would melt. It could get nicked and short + to -. Before it melts, it will start to glow. Giving off poisonous fumes. As it glows, it could ignite anything nearby. By the time that speaker wire melts and opens electrically, the room could be already on fire.


Take a look at the schematic below; what would happen if the 10 m long wires got nicked and shorted at the 'X'? (think like a door closing on it, or a dog gnawing on the cables) What would happen if you had a fuse? What would happen if you hadn't one? Do you see the total irrelevance of any diode? Do you see what would happen if the fuse was placed at/near the diode?


So, now you know too that you want the fuse as close to the battery as possible.


BTW, I'm 99.9% sure your setup wouldn't burn down your house. With a fuse, I'd be 99.99% sure. 25 years of experimenting and tinkering with electronics has made me very cautious.


Your dad is a clever man. Good thing you listen to him.




« Last Edit: September 20, 2006, 01:12:01 PM by dinges »
“Research is what I'm doing when I don't know what I'm doing.” (W. von Braun)

AbyssUnderground

  • Sr. Member
  • ****
  • Posts: 461
Re: My new 18w eBay solar panel
« Reply #8 on: September 20, 2006, 01:20:39 PM »
I do see your point but I just prefer to keep things simple until Im happy with it. ive never used a fuse in anything except those things that come with them and Ive not "yet" had an issue. But I see your point, and as I said Ill be putting one in ASAP.
« Last Edit: September 20, 2006, 01:20:39 PM by AbyssUnderground »

AbyssUnderground

  • Sr. Member
  • ****
  • Posts: 461
Re: My new 18w eBay solar panel
« Reply #9 on: September 20, 2006, 01:30:59 PM »
Also id like to add that my diode is nearest the battery in the charge controller. There are none on the panels. There is about 30cm of cable between the charge controller and battery.
« Last Edit: September 20, 2006, 01:30:59 PM by AbyssUnderground »

Titantornado

  • Sr. Member
  • ****
  • Posts: 290
  • Country: us
Fuses can't save everything, but they don't hurt
« Reply #10 on: September 20, 2006, 01:52:55 PM »
As dinges points out, it's only 99.99% assurance as I can think of one case where the fuse won't do you any good in a condition that can potentially start a fire.  


I was called by a friend of mine to come down to diagnose his RV's electrical system that wasn't working.  I located the problem in his AC/DC distribution box, where a loose connection on the main DC buss had burned the insulation back several inches and eventually burned the wire clean off the lug.  The buss insulators and several breakers were also damaged by the heat created by that loose connection.  No fuses or breakers can prevent this, since the amperage is never exceeded.


Just food for thought.  If you follow NEC, there's probably only about 0.01% chance you'd ever have a problem. (as dinges notes)

« Last Edit: September 20, 2006, 01:52:55 PM by Titantornado »

AbyssUnderground

  • Sr. Member
  • ****
  • Posts: 461
Re: Fuses can't save everything, but they don't hu
« Reply #11 on: September 20, 2006, 01:55:47 PM »
Ive seen this one happen before in a 12kW shower. The whole of the plastic connection block burned away. Even though the shower was still working you could smell the burning whenever you used it.
« Last Edit: September 20, 2006, 01:55:47 PM by AbyssUnderground »

stephent

  • Sr. Member
  • ****
  • Posts: 268
Re: My new 18w eBay solar panel
« Reply #12 on: September 20, 2006, 10:11:57 PM »
Best place to put a fuse would at the battery and closer then the distance between the closest battery posts. And one just after the PV panels wouldn't hurt much either.

Just make sure the fuse voltage range is proper for the voltage of the system.

Don't use a 12/24 volt (automotive type--32 volt actually rated I think) for a higher voltage, they might not "quench"/absorb the arc that results and actually explode.
« Last Edit: September 20, 2006, 10:11:57 PM by stephent »