[RE-wrenches] Solarworld diodes

[Bill Hoffer]

Ron

Technically removing the junction box has voided the warranty and the UL
listing of the module,field modification is not covered by the manual.
 Solarworld probably will not accept a warranty claim after the customer
has done that.  Considering that diode failure is relatively common (
Schottkey diodes are susceptible to surge damage from lightning and near
strikes among others), I am disappointing that Solarworld would encapsulate
diodes that cannot be field repairable, unless they are using the newer
surge resistant switching diodes that have a better chance of a 30 year
life ( and cost 10X cheap schottkey didoes).

That being said and assuming this is an off grid application that is under
the AHJ's radar,  there are replacement junction boxes available to
salavage the situation, just make sure you check the diode specs and that
they exceed the Solarworld diode specs ( I could not find it for that
module) .  Should be UL listed for the module Max Voltage rating , beware
Chinese knockoffs, buy from a reliable source!   Rough rule of Thumb, Diode
needs to be rated at the max breaker size current + 25 - 50%  to account
for temperature and current derate.  ST has a great application note
AN3432<http://www.st.com/st-web-ui/static/active/en/resource/technical/document/application_note/DM00034029.pdf>if
you want to geek out on the details....  Look for a solderless
clamping
terminals or at least one that is spaced off the back of the module to make
sure that you do not damage the back sheet when soldering, this connection
is critical and a source of future failures in modules from over-heated
poor solders.  A Larger Junction box is better for heat dissipation with
the diode away from the back of the module and to cover any damage that the
removal of the existing JB may have done to the backsheet. You will want to
get a 2 part potting compound like Dow Corning
PV7010<http://krayden.com/tds/dow_pv-7010_tds.pdf>to insure that
penetrations and any damage to the backsheet is sealed from
moisture, a source of future delamination and corrosion issues. If you are
lucky you can get a dual syringe sample that should be good for several
modules.

IMHO junction boxes should be as large as possible and have access to the
didoes that are above the penetration potting material.  Even at sun
$1/watt pricing it is stupid to let a module to have an early demise when
replacing $.75 worth of diodes would get it up and running again!

Good Luck!

Bill


On Fri, Feb 28, 2014 at 2:34 PM, RM You <solareagle at solareagle.com> wrote:

> Hi wrenches, I sold some 175w Solarworld panels a few years ago and the
> diodes have blown on one. Customer isn't clear on why it happened and is
> taking the 5th but what I'm trying to find out is how to help him get the
> panel working again. He removed the Jbox off the panel, which is a low
> profile model with diodes moulded right into the casing. Would it be
> possible to replace this Jbox? Anyone have experience with Solarworld
> supplying replacement boxes? I have a couple of pics and will post them but
> not sure if the list allows pics.
>
> Thanks!
> Ron Young
>
> THIS IS THE REMNANTS OF THE DIODE WITH THE PLASTIC CAP SCRAPED OFF
>
> THIS IS THE J BOX
>
> _______________________________________________
> List sponsored by Home Power magazine
>
> List Address: RE-wrenches at lists.re-wrenches.org
>
> Change email address & settings:
> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org
>
> List-Archive:
> http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org
>
> List rules & etiquette:
> www.re-wrenches.org/etiquette.htm
>
> Check out participant bios:
> www.members.re-wrenches.org
>
>
>


-- 
William Hoffer
161 SE Fourth Ave
P.O. Box 1823
White Salmon, WA 98672-1823
sunengser at gmail.com <bhoffer at sunergyengineeringservices.com>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20140301/1066e2d4/attachment-0003.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: IMG_1896.jpg
Type: image/jpg
Size: 129865 bytes
Desc: not available
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20140301/1066e2d4/attachment-0012.jpg>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: IMG_1895.jpg
Type: image/jpg
Size: 141045 bytes
Desc: not available
URL: <http://lists.re-wrenches.org/pipermail/re-wrenches-re-wrenches.org/attachments/20140301/1066e2d4/attachment-0013.jpg>