Thanks Daniel! On Monday, July 6, 2015, Daniel Young <dyo...@dovetailsolar.com> wrote:
> Hey Gary, > > > > Basically the area of the dropping will lower the current of that module > (and the current of that string if this is a string inverter). The amount > of current loss will be the % of the dropping area vs the area of the cell > it landed on. Voltage won’t be affected by things the scale of a few bird > droppings. > > > > If this is a string inverter, theoretically if one module on the string > took a hit, then every other module on the string can take a hit too and > not really increase the impact, as they are all already current limited by > the first module to take a hit. The current of that string will just be the > same as the current from the most affected module in the string. So > multiple droppings really don’t have a big additive affect. > > > > Assume all birds drop the same size load (you’re not getting seagulls over > there so you’re talking starlings, robins, barn swallows, all similar size > :) once one module in a string is hit, there will not be any further impact > on production until some module in the string gets 2 hits on the *same > cell on the same module.* Cells are just a string mounted in a module > frame. So you could have a module with 5 droppings on it if they were all > on different cells, and it would do the same as a module with just one > dropping, if they were all the same size. > > > > At some point that above example breaks down, because the bypass diodes > will start to kick in if one cell grouping gets hit too hard. > > > > As for where on the module….untill you get to the point where bypass > diodes are kicking in, I don’t think there is a difference. And at what > point would the diodes kick in, you’d need to get an I-V curve tracer out > and play around with paintballs or something to help quantify that J > > > > That’s the way I understand it at least. I have not gone out with my I-V > tracer and dug into this in detail. It’s just based of the core parallel vs > series wiring of the typical PV source circuit. I have not seen much impact > to date from bird droppings on our Solaredge installs so far (the ones I > KNOW where hit by birdie bombers were so close to those that weren’t that I > can’t pick them out on the monitoring portal, they just look like typical > manufacturing variances [all within the +/- x% power tolerances]) > > > > With Regards, > > > > Daniel Young, > > NABCEP Certified PV Installation ProfessionalTM: Cert #031508-90 > > Lead Systems Designer for: > > [image: Dovetail 2013 cmyk 300dpi.jpg] > > *www.dovetailsolar.com <http://www.dovetailsolar.com>* > > Ph: 740-274-0139 > > > > We’ve completed nearly 400 renewable energy projects! Check out a few in > our photo gallery: > *http://www.dovetailsolar.com/Our-Work.aspx?path=commercial+-+solar+electric > <http://www.dovetailsolar.com/Our-Work.aspx?path=commercial+-+solar+electric>* > > This email message and attachments are intended only for the addressee. > It may contain information which is legally privileged, confidential and > exempt from disclosure. If you are not the intended recipient of this > message, you may not disclose, print, copy or disseminate this message > and/or the information contained in the message. If you have received this > message in error, please reply and notify the sender (only) and delete this > message along with any attachments. Unauthorized interception of this > email is a violation of criminal laws and laws covering electronic > communications privacy matters. > > > > *From:* RE-wrenches [mailto:re-wrenches-boun...@lists.re-wrenches.org > <javascript:_e(%7B%7D,'cvml','re-wrenches-boun...@lists.re-wrenches.org');>] > *On Behalf Of *gary easton > *Sent:* Monday, July 06, 2015 3:36 PM > *To:* RE-wrenches > *Subject:* [RE-wrenches] Bird droppings > > > > I have a customer with a bit of a bird problem. The array is ground > mounted and can be easily cleaned but he is wondering what the impact of > for instance droppings on one cell. And how it adds up. Is there a rule > of thumb for this? Does it depend where the cell is located in the module? > > > > -- > Sent from Gmail Mobile > ------------------------------ > > No virus found in this message. > Checked by AVG - www.avg.com > Version: 2012.0.2250 / Virus Database: 4365/9671 - Release Date: 07/06/15 > -- Sent from Gmail Mobile
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