[RE-wrenches] Sanyo HIT module diode issues

[Brian Mehalic]

Did you use the Diode Test function on the meter?  If the diode is good you
should see around 0.4-0.8 V in the forward bias, and OL in reverse.  If it
is bad (open) you'll get OL in both directions, and if it is shorted closed
you'll get the 0.4-0.8 V reading in both directions.

Shorted closed would be the failure mode that would indicate an
always-closed diode providing a permanent bypass path and thus a drop of
25% of voltage per bad diode (or set of paralleled diodes).  (These have 4
diodes right?).




Brian Mehalic
NABCEP Certified Solar PV Installation Professional™ R031508-59
520.204.6639

Solar Energy International
http://www.solarenergy.org

SEI Professional Services
http://www.seisolarpros.com


On Thu, Jul 6, 2017 at 4:31 PM, Taiyoko Sadewic <
taiyoko at positiveenergysolar.com> wrote:

> Hi Wrenches,
> We were installing Sanyo HIT modules back in 2006-2007 and in 2014 we had
> a rash of bad Sanyo modules. The modules had distinct voltages below the
> good modules ie 50% or 75%.  Sanyo at the time (now Panasonic) indicated
> that it was a bad diodes from a lightning strike not covered by warranty.
>
> I finally got around to checking that out. I identified the purportedly
> bad diode in one module (four per module) that was performing at 75% and
> removed it. The diode appears to be fine using an ohm meter.  Is that a
> valid test?
>
> Anyone else have similar findings or experiences with this?  Could
> lightning blow apart the tab ribbons inside of the module?
>
> Thanks
>
> --
> <http://www.PositiveEnergySolar.com>
> Taiyoko Sadewic
> Employee-Owner
> NABCEP™PV Installation Professional
> NABCEP™Technical Sales
> 3209 Richards Lane  |  Santa Fe, NM 87507
> cell  505.570.0137 <505.699.9032>
> Taiyoko at PositiveEnergySolar.com  <Taiyoko at PositiveEnergySolar.com>
> www.PositiveEnergySolar.com
> <http://www.positiveenergysolar.com/>
>   <http://www.facebook.com/positiveenergysolar>
> <https://twitter.com/PositiveESolar>
> <https://plus.google.com/+Positiveenergysolar>
> <https://www.youtube.com/user/PositiveEnergySolar>
> <https://www.positiveenergysolar.com/blog/blog/>
>   <https://www.positiveenergysolar.com/contact/refer-a-friend/>
> <https://www.bcorporation.net/community/sunpower-positive-energy-solar>
> <http://www.solarreviews.com/installers/positive-energy-solar-reviews/>
>
> _______________________________________________
> List sponsored by Redwood Alliance
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change listserver email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive: http://www.mail-archive.com/re-wrenches@lists.re-wrenches.
> org/maillist.html
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out or update participant bios:
> www.members.re-wrenches.org
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20170706/9f49aabd/attachment-0002.html>