[RE-wrenches] mix-n-match Unisolar

[Geoff Greenfield]

Thanks Tony - yes, that approach makes perfect sense.  Unfortunately, this design ends up with plenty of lower voltage strings paralleled with higher ones. 


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 






----- "Antony Tersol" wrote: 
> 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 > Subject: [RE-wrenches] mix-n-match Unisolar > To: RE-wrenches > Cc: Randy > Message-ID: > <7296183.5724731225398578887.JavaMail.root at 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 > > > 
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