<html><head><style type='text/css'>p { margin: 0; }</style><style type='text/css'>body { font-family: 'Times New Roman'; font-size: 12pt; color: #000000}</style></head><body>Thanks Tony - yes, that approach makes perfect sense. Unfortunately, this design ends up with plenty of lower voltage strings paralleled with higher ones.<BR><BR>
<DIV>For a brighter energy future,<BR><BR>Geoff Greenfield<BR>Founder and CEO<BR><FONT size=4><STRONG>Third Sun Solar & Wind Power Ltd.<BR></STRONG></FONT>340 West State Street, Unit 25<BR>Athens, OH 45701<BR><BR>740.597.3111 Fax 740.597.1548<BR>www.Third-Sun.com<BR><BR><EM><FONT size=4>Clean Energy - Expertly Installed<BR></FONT></EM><BR><BR><BR><BR></DIV><BR><BR>----- "Antony Tersol" <TONY@APPLIEDSOLARENERGY.COM>wrote: <BR>> If you had, for instance, strings of quantity 10 PVL136 watt modules, and you needed to put in a 68 watt module because of a skylight, then you would want to use a string of 9 PVL136 watt + 2 PVL68 watt. This would keep the voltages the same between strings. Having a string of 9 PVL136 + 1 PVL68 paralleled with strings of 10 PVL136 would cause some of the strings to see non-optimal voltages. I don't see how bypass diodes would fix things. > Message: 1 > Date: Thu, 30 Oct 2008 13:29:38 -0700 (PDT) > From: Geoff Greenfield <GEOFF@THIRD-SUN.COM>> Subject: [RE-wrenches] mix-n-match Unisolar > To: RE-wrenches <RE-WRENCHES@LISTS.RE-WRENCHES.ORG>> Cc: Randy <RANDY@THIRD-SUN.COM>> Message-ID: > <7296183.5724731225398578887.JavaMail.root@zimbra4.mindcentric.com> > Content-Type: text/plain; charset="utf-8" > > > > I thought I knew the answer to this one, but wanted to run it by the list. > > > > We are responding to a bid where the electrical engineer has designed a > system with different sized Uni-solar laminates in some?series strings > paralelled with consistant full size strings.? (this was done to work around > skylights etc). > > > > We suggested that this was a poor design and will lead to "least common > denomenator" performance, exacerbated by MPPT confusion.? The EE responded > that "the bypass diodes allow for this". > > > > Any experience with this in practice? > > > For a brighter energy future, > > Geoff Greenfield > Founder and CEO > Third Sun Solar & Wind Power Ltd. > 340 West State Street, Unit 25 > Athens, OH 45701 > > 740.597.3111 ? ? Fax 740.597.1548 > www.Third-Sun.com > > Clean Energy - Expertly Installed > > > <BR>> _______________________________________________ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.org Options & 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 </body></html>