Measuring solar panal output (or lack of it)

[Plasticman]

My van has a panal on the roof, its about 18' x 14' 2 wires in the van from it , if I connect a meter it gives 16 - 18 volts so something is coming out of it but how do I measure how much, that is to say how do I connect up the M meter.
its not the best condition but its fitted and its free.
mike

[AngeloEvs]

Max output voltage is obtained in unobstructed sunlight with the panel facing directly into the Sun. A typicial reading on a Solar panel can be anywhere between 18 -23V under no load (solar panel not connected to anything). Unfortunateley, this reading alone isn't a fat lot of use with SolarPanels as they can produce the correct output voltage but not the max current as cells start to die or lose efficiency with age - what you really want to know is if any of the cells are dud. I would set the panel up facing Bright sunshine, set my meter to DC Amps so that it can measure in excess of 5A and connect the two leads from the multimeter to the two leads on the solar panel and measure the 'short circuit' current. You really need to have the manufucterers spec to establish just how efficient it is and how close your reading are to what they should be.
You might find it worthwhile to do a google search on 'testing Solar Panels' as there is loads of info and advice on tracking down faulty cells.


E D I T. found this on a Google search......there's tons of info on the WEB.

.http://www.youtube.com/watch?v=fkook28HhWI