[RE-wrenches] Trouble Shooting Bad Diode

Kirpal Khalsa solarworks at gmail.com
Fri Oct 31 10:43:08 PDT 2008


Greetings all......I was hoping i could have someone help me confirm a
troubled series string on a system we have installed.....
System consists of 16 BP 170 W 24V nominal modules......2 strings of 8
modules.....Vmp of each module is roughly 34V and Voc of each module is
roughly 41V.  One string is under-producing......String 1 Voc is 346V and
String 2 Voc is 272V.  String 1 Vmp under load is 270V and String 2 Vmp
underload is 270V.  I am hypothesizing that String 2 has a bad diode on the
3rd panel in and is reducing the Voc of that string by th 2 panels ahead of
it in the string.  I am hoping to figure this out without removing the
entire string and checking each panel if possible.....
I think the Vmp is equal due to the fact that both strings are paralleled in
the inverter and the 1st string is being pulled to the same level V as the
2nd string under load......Is my logic good?
Thanks for the help and advice.....
Cheers,
Kirpal Khalsa
Renewable Energy Sytems
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20081031/fd1c95b1/attachment-0002.html>


More information about the RE-wrenches mailing list