No voltage from my solar panels!!

[gypo]

Just came back from a weekend trip and noticed that my solar charge controller wasnt showing any voltage going in from the solar panels? They were working fine last night and this morning.
They have been fitted since March with no problems.
My setup 2x 100w semi flexi solar panels wired in parallel to a Tracer mttp controller.
I checked the wires right back to the tails coming out from the panels and no voltage?
Anyone got any ideas please what it could be?
Thanks
G

[Oldiebut goodie]

Usually dry solder joint does this - worth checking the soldering of the wires on the panel connection to the tail. Vibrations doesn't help these. (usually panel to a diode then the tail)

[gypo]

Thanks for the reply

On the top of each panel is a connection box that is filled with that waterproof stuff that wont let you int it, you can just see a diode through it. It would be a bit of a coincidence for the two to go at the same time tho wouldn't it?
Thanks
G

[Oldiebut goodie]

Are the tails separate to the controller or is there a junction somewhere before? Yes, odd for both to go at the same time, so......Don't forget to check the earth connections also, not just the live.

[gypo]

There is a small connection box mounted on top of each panel, when you remove the lid it is filled with that water proof stuff (all sealed) you can just make out a diode in the one through the sealant. The wires come out of the box, I have tried a voltage meter on the wires with no results?
Ive checked the rest of the wire for continuity thinking that they may have shorted out but it was ok.
I cant think of anything else?
Cheers
G

[Oldiebut goodie]

Not being silly but have you checked that your multimeter is working? I have an Avometer that my neighbour gave to me which only worked intermittently - eventually found that a lead had fractured internally. This has got me puzzled as you normally get a few volts even with a light bulb shining on a panel.

[gypo]

Yes, also tried another and tested them both on the battery.
G

[ethelred the ready]

Are they Biard solar panels? I had this exact same problem, dig out the silicon, it's quite brittle so easy to shift. My diode was OK on testing, but two dry soldered joints. Resolder with powerful electric or had iron, should work.

[ethelred the ready]

whoops put the same photo twice!

[ethelred the ready]

I think I should have another cup of tea, my brain isn't working.

[gypo]

Yes that looks like them, I'll check they are the same tonight.
How did you check the diode?
Thanks for the info
G

[ethelred the ready]

The diode will only allow current through in one direction. Set a multimeter to ohms and you should only get a reading when the leads are connected one way, the other way will show a very high resistance. Out of interest, where did you buy your panels from?

[gypo]

Thanks for the info, I'll try and check them tonight,
I bought them from this seller http://www.ebay.co.uk/usr/bestecoshop
Thanks
G

[gypo]

I went out to the van to start testing the panels and thought I'd re-connect the " solar panels in" wire back to the control unit and it's now working? The van hasn't moved since parking it up yesterday so no chance that I've moved any wiring but now it's working again?
G

[Oldiebut goodie]

Bad solder joints can do that - often. Still worth checking them out.