How are strings in 50W modules connected?
System
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I would honor a reasonable request for reimbursement for time in sketching a correct diagram, including a follow up question or two.
The new owner of forty off-spec 300W modules (150W as delivered) asked me to find a way to access the capacity that has been disabled.
As designed, the module has six strings in series for 50V. As supplied, three strings are connected in series for a 25V module. Three strings are disabled.
One of the disabled strings is visibly damaged. I am investigating the possibility that the other two strings may be accessed to create a separate power supply.
Some testing to determine the condition of the two strings is necessary, however, I cannot figure out how the strings are connected. See the attached photo of the junction box (I removed the bar between the diodes for clarity).
Three ribbons on the (-) side are cut. Three on the (+) side are intact. This corresponds to the panel locations of the three good and three disabled strings.
One ribbon is connected to the (-) side, with all the junctions on that side shorted.
If someone would provide me a simple circuit diagram of how the strings are connected, indicating pos. and neg. circuits, I would honor a reasonable request for reimbursement. I've searched the internet and not found anything except simpler 2-string circuit diagrams. Much thanks.
The new owner of forty off-spec 300W modules (150W as delivered) asked me to find a way to access the capacity that has been disabled.
As designed, the module has six strings in series for 50V. As supplied, three strings are connected in series for a 25V module. Three strings are disabled.
One of the disabled strings is visibly damaged. I am investigating the possibility that the other two strings may be accessed to create a separate power supply.
Some testing to determine the condition of the two strings is necessary, however, I cannot figure out how the strings are connected. See the attached photo of the junction box (I removed the bar between the diodes for clarity).
Three ribbons on the (-) side are cut. Three on the (+) side are intact. This corresponds to the panel locations of the three good and three disabled strings.
One ribbon is connected to the (-) side, with all the junctions on that side shorted.
If someone would provide me a simple circuit diagram of how the strings are connected, indicating pos. and neg. circuits, I would honor a reasonable request for reimbursement. I've searched the internet and not found anything except simpler 2-string circuit diagrams. Much thanks.