PV Overview

PV Array

Ralph & Chris take the first module out for testing with the VOM meters. Five minutes later we knew we were dealing with 6 volt modules.

The open circuit voltage measured just under 10 volts on each module. The short-circuit current varied quite a bit of course given the variation in sunlight. Voltage doesn't change too much with sunlight level so that is our best on-site performance test.

Sean and Chris Hall run module interconnect wires to the combiner box. We considered very briefly running THHN in flexible conduit, but we had single wire, stranded USE-2 which meets the Code and was much easier to work with.

A positive and negative wire run from each 6-volt module to the combiner box where they are connected in series. A 24-volt positive and negative pair of wires exit the combiner box in flexible conduit to permit movement of the array. These wires run to the other array to which they are connected in series.

Mark Froling checks the open circuit voltage of the array to make sure we have made the series connections properly. So far so good.

Open circuit voltage for these 4 modules in series is just under 40 volts DC. By the time we series this sub-array with the 2nd sub-array, our 48 volt (nominal) PV system will have an open circuit voltage of about 80 volts DC.
!! Careful !!


	The lower larger box is the junction box where the wires from the two arrays will be connected in series and connect to the cables running to the power center in the basement of hte house. You can see the two 1/0 cables ( and #4 ground are ready to be pulled through the conduit to the house. The upper box is the 2-pole safety switch. The positive wire from each array runs through a fuse and disconnect switch.

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