[RE-wrenches] posting request
Dear Wrenches Can anyone recommend a software package that is good for solar electric project management? We would like to be able to have the capability to coordinate scheduling, procurement, budgeting, expense tracking as well as noting communications about a given project. If an integrated package doing all these things doesn’t exist we’re especially interested in just good stand-alone procurement software that takes projects from BOM, to request for bids, to POs and invoices. Thanks. Steve McCarney, Project Manager Solar Electric Light Fund ___ 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
Re: [RE-wrenches] posting request
Steve, Have you checked out SolarNexus? http://www.solarnexus.com/ As I understand it, their goal is to provide all of the functionality you describe in a single platform. Best regards, David Brearley, Senior Technical Editor SolarPro magazine NABCEP Certified PV Installer ™ david.brear...@solarprofessional.com Direct: 541.261.6545 On Sep 17, 2012, at 12:08 PM, Steve McCarney wrote: Dear Wrenches Can anyone recommend a software package that is good for solar electric project management? We would like to be able to have the capability to coordinate scheduling, procurement, budgeting, expense tracking as well as noting communications about a given project. If an integrated package doing all these things doesn’t exist we’re especially interested in just good stand-alone procurement software that takes projects from BOM, to request for bids, to POs and invoices. Thanks. Steve McCarney, Project Manager Solar Electric Light Fund ___ ___ 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
[RE-wrenches] Short Circuit Cell Damage
Wrenches, True or False: In a nominal sort of grid tied situation with string Voc at about 300 VDC and Isc at about 6 or 7 amps..It is OK to install modules on a roof in the sun and short the pos and neg together indefinitely. In other words modules can handle operating at Isc continuously without damage. It is only if you get localized shading AND a failed bypass diode that damaging hot spot heating can lead to failure? I am reviewing an installation manual that recommends completing the home run by connecting the pos and neg of the string with a single jumper cable, folding the cable on itself in order to push it through to a j-box and at some point later on, cutting the jumper in the j-box to terminate the pos and negs to the home run. I am concerned both about maintaining the string in a short circuit condition and cutting the jumper while energized. Any thoughts? Mark Frye Berkeley Solar Electric Systems ___ 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
Re: [RE-wrenches] Short Circuit Cell Damage
Mark, Think about this: the Isc current is only slightly higher than Imp. Picture a series DC circuit. Both short circuit and operating current are loads on the PV module(s). An indefinite short will not be a problem any more than operating the module at higher than 1000W/M/2. Neither will there be any more potential for hot spot damage than in normal operation. When you cut the jumper, watch out for the arc! Larry Crutcher Starlight Solar Power Systems On Sep 17, 2012, at 9:50 PM, Mark Frye wrote: Wrenches, True or False: In a nominal sort of grid tied situation with string Voc at about 300 VDC and Isc at about 6 or 7 amps..It is OK to install modules on a roof in the sun and short the pos and neg together indefinitely. In other words modules can handle operating at Isc continuously without damage. It is only if you get localized shading AND a failed bypass diode that damaging hot spot heating can lead to failure? I am reviewing an installation manual that recommends completing the home run by connecting the pos and neg of the string with a single jumper cable, folding the cable on itself in order to push it through to a j-box and at some point later on, cutting the jumper in the j-box to terminate the pos and negs to the home run. I am concerned both about maintaining the string in a short circuit condition and cutting the jumper while energized. Any thoughts? Mark Frye Berkeley Solar Electric Systems ___ 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 ___ 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
Re: [RE-wrenches] Short Circuit Cell Damage
Mark, Shorting the string should not be an issue. Unless you work at night, obviously there will be an arc when you cut the jumper, so remember to cover the whole string with an opaque covering beforehand I think I remember reading that somewhere?!?! Or just be careful, try to do it when the irradiance is low (less current), separate the cut wires quickly and make sure you have left enough wire in the box so that you are not working with short (and energized) wires in a metal box. put a wire nut on one wire while you handle and terminate the other. A safer method, if possible, would be to leave an easily accessible module interconnection un-connected until you have terminated the home run (+)(-), then go back and make the final module interconnection. Cheers, benn DayStar Renewable Energy Inc. www.daystarsolar.ca * Ph: 780-906-7807 Construction Electrician Solar Photovoltaic Systems Certified Certificate # 0007S HAVE A SUNNY DAY On 17/09/12 9:50 PM, Mark Frye ma...@berkeleysolar.com wrote: Wrenches, True or False: In a nominal sort of grid tied situation with string Voc at about 300 VDC and Isc at about 6 or 7 amps..It is OK to install modules on a roof in the sun and short the pos and neg together indefinitely. In other words modules can handle operating at Isc continuously without damage. It is only if you get localized shading AND a failed bypass diode that damaging hot spot heating can lead to failure? I am reviewing an installation manual that recommends completing the home run by connecting the pos and neg of the string with a single jumper cable, folding the cable on itself in order to push it through to a j-box and at some point later on, cutting the jumper in the j-box to terminate the pos and negs to the home run. I am concerned both about maintaining the string in a short circuit condition and cutting the jumper while energized. Any thoughts? Mark Frye Berkeley Solar Electric Systems ___ 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
