locating break in DC circuit - remotely

[malua mada!]

I have some photovoltaic panels with intermittent contacts. When I
flex / press on the back of the panel the output will (sometimes)
reach nominal values, otherwise remain low (not zero)
The break is somewhere in the general real estate and not at the lugs.
The back of the panel is covered by plastic + aluminum foil, glued no
doubt by state of the art process 1990. Removing the foil to find the
bad spot(s) is not a likely option - skinning the patient to set a
bone - but if I can pinpoint the break I'll go in! Is there a signal
I can feed into the panel from the lugs, and map the traces with some
kind of pickup?
Thanks
Fritz

 

[Joerg]

malua mada! wrote:

I have some photovoltaic panels with intermittent contacts. When I
flex / press on the back of the panel the output will (sometimes)
reach nominal values, otherwise remain low (not zero)
The break is somewhere in the general real estate and not at the lugs.
The back of the panel is covered by plastic + aluminum foil, glued no
doubt by state of the art process 1990. Removing the foil to find the
bad spot(s) is not a likely option - skinning the patient to set a
bone - but if I can pinpoint the break I'll go in! Is there a signal
I can feed into the panel from the lugs, and map the traces with some
kind of pickup?
Thanks
Fritz

You could try a 500Hz sawtooth or square wave, a few hundred mV, and
pulse this (for easier listening). Hook it to one side of the panel, the
other side to ground (desk frame, whatever). Take an audio amp or a
sound card and connect a coax to it. Shield goes to same ground (short
distance). Solder a penny-sized plate to the center of the coax and then
follow the trace. At the break you should notice a drop in amplitude.

Be careful, I don't know if there could be any toxic stuff in there if
you dig into a solar panel.

--
Regards, Joerg

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