On inspection the panels had no labels or manufacture's markings except a barcode:.
I tried to find the barecode by searching the Internet without success. Also, It is not listed on the Australian Clean Energy database of CEC approved PV modules:
Detail of the Solar Panel Validation initiative can be found here: http://www.cleanenergyregulator.gov.au/RET/Scheme-participants-and-industry/Solar-Panel-Validation-initiative
If anyone has information about the source if these panels I would appreciate an email.
I purchased two panels, so I placed both in direct sunlight near the middle of the day.
First, I connected a voltmeter to the leads and tilted the panel to maximise the voltage.
Then, I connected an ammeter directly to the leads and also titled the panel to get the maximum
current reading. I repeated this for the second panel.
The results for both panels were close to identical: Voltage: 20.5, Current: 4.2 Amps That calculates to 86.1 Watts. Certainly NOT a 250 Watt panel.
Even after making some allowance the ambient temperature, solar cells temperature, solar irradiance, and losses in the tes equipment this panel falls far short of the claimed 250 Watt nominal output.
I would suggest it is nominally a 100 Watt panel.