Tests For Solar Generation Expectations

Are there any tests I can do to get an idea of the solar capabilities from solar panels installed on my roof?

There are meters that professional installers will use if there are shading problems on your roof. They sit on your roof and tally up the amount of light received for say a week. If you don't have that problem you can get a rough idea of how much sunlight your roof receives from insolation maps available via google searches. Even a Google search for your area 'average hours of sunlight' will give useful information.

Are you asking from the point of 'is it worth doing this' or 'right, I have panels now am I getting my money's worth' ?

plr said:

Are there any tests I can do to get an idea of the solar capabilities from solar panels installed on my roof?

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Easiest test is a simple voltage/amp test. With the wires disconnected from the solar charger, measure the voltage across the wires in full sun. It should be close to the VoC value on your panel. Then use an ammeter across the same wires. It should also be close to the ISC value. if you have multiple panels in series, multiply the voltage reading you got by the number of panels for the total voltage. If you have multiple panels in parallel, multiply the amps value you got by the number of panels.
This is just a very simple test to verify the panels are working at rated spec. Like @gnubie said above, any testing beyond that requires more than a voltmeter.

I've heard this question before and it's a good one. Started a working FAQ thread on it here: Diagnosing Problems with a Photovoltaic System

From @svetz FAQ:

Voltages
THIS CAN BE DANGEROUS!

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Do not attempt unless you know what your're doing!

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Agreed. I was thinking in terms of single or two panels, and have years of experience (read as 'respect') with electricity.

Thanks for all the replies. Mostly I am concerned about shade. I took two large trees down but still have at least one more that needs to be at least trimmed,

Even so part of my house gets decent afternoon sun and I was wondering if sun meters for gardens would work to get decent info on the quality of sunlight that part of roof receives?