Solar Consumer Reporting

solar good and bad equipment


                                  Solar panels produce DC power which is basic electricity so here is some basic information.


SERIES   versus Parallel Connections , see the link above for wikipedia information.

Solar panels make DC electricity. Most panels make 6 or 12 volts. To get a higher voltage like 48 volts you have to connect them in series. This connects the positive of one panel to the negative of the next panel and so on until the very first open connection and last one has a potential of 48 volts. So if they are 12 volt panels at 4 amps each we need 4 connected together in series.


   -----+----| +         -  |------------| +      -|----------|+        - |-------------| +      -|----------

                 12 V                       12 V                     12 V                      12v                 = 48 volts DC at 4 amps

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If you  want the same voltage but more amps you connect them in Parallel , Positive to positive, and negative to negative.

2 12 volt 4 amps panels connected in Parallel is 12 volts but at 8 amps.

          -| +             -- |-                                                                                     = 12 volts at 8 amps

    -|+               - |-


Use a VOLT/OHM meter, set for DC volts ------ not AC ~~~~~~~~~

1ST-Set it on volts  , place the panels in direct sun with no shadows on the face of the panel.

Measure the open circuit voltage from the + positive terminal to the - negative. a 12 volt panels should be about 14-22 volts or so. Be SURE the PANEL: IS IN FULL SUNLIGHT on a clear Sunny day. Arizona has 330 of these a year ! I get reading above the STC standard Test Conditions since we have such great clear sunlight.

Measure the same place but with a load on the + to - . This can be a DC fan or DC light. The voltage should be about 14 volts DC

Last set the meter to measure AMPS- Be sure the meter can handle the amps the panel makes. IE most panels are 4-6 amps. the meter should be rated at 10 amps or more. To read the amps, connect the leads of the meter to COM common and AMPS, BE CAREFUL SINCE THIS IS LIKE A SHORT CIRCUIT WHEN YOU CONNECT IT. Now set the meter to read the highest amps setting and connect the meter to the same + - panel terminals, be sure to have the polarity correct or you may not see any amps. Don't leave it for a long time, just 10 to 20 seconds is enough. Records the AMPS.  As soon as you have read the AMPS put the meter test leads back to COM and VOLT-OHMS so you don't make a short circuit next time you use the meter.

Now check you results againt the panel label on the back of the panel. It should be very close. In AZ I read higher than standard.