Re: [RE-wrenches] Snow loads
Jeffrey, I agree. We do structural analysis on every roof design and factor in the point loading at the attachment points. I had floated this idea because it came from an SE that I work with that also has a PV system. His theory is the definition snow loads are accumulation of snow over time. And most of the time snow will slide off the panels in 3-4 days. The panels would have to be placed so the snow would completely slide off the roof. I wanted to see what others thought of this approach who have been doing structural analysis. I appreciate your responses. Gary From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of JRQ Sent: Thursday, February 21, 2013 8:28 PM To: RE-wrenches Subject: Re: [RE-wrenches] Snow loads Gary, The snow loads that structural engineers design to are a worst-case scenario. It is true that snow tends to slough off of PV arrays quicker than your normal roof. However, if there is a major snow event, especially if it starts at night (this recent blizzard on the East Coast would be a good example), snow will build up on the array the same as it does everywhere else. In many cases, a PV array actually makes the engineering assumptions worst. Any snow that lands on the modules transfers down to the attachments, and point-load the structural members. The weight of the snow is less distributed when it sits on a PV array, placing additional stress on individual members. I work in Massachusetts currently, and we often have to perform rafter upgrades to roofs that are fine otherwise for exactly this reason. If you have any snow load requirements in your area, I would highly recommend you have a structural engineer review the structure, even if a structural stamp is not required. Jeffrey Quackenbush From: Bob-O Schultze bo...@electronconnection.commailto:bo...@electronconnection.com To: RE-wrenches re-wrenches@lists.re-wrenches.orgmailto:re-wrenches@lists.re-wrenches.org Sent: Tuesday, February 19, 2013 3:00 PM Subject: Re: [RE-wrenches] Snow loads I would certainly agree with Will here. You can't make that argument as stated, it's wrong. Please don't try to make it to your AHJ, you take the chance of f-ing it up for everyone around there. I think the best argument you can try is: aside from the usual 3-4lbs/sq/ft that the array itself ads to the roof load, snow will be very unlikely to build up on the modules to the degree that it builds up anywhere else on the roof. The freezing-rain-before-a-snow phenomena is very real and it WILL happen sooner or later. Not often perhaps and under most conditions the snow will leave the modules before the roof. But...Gotta be real about that. Bob-O Schultze On Feb 19, 2013, at 11:06 AM, Will White wrote: Most structural engineers I’ve seen take a reduction for slippery surface but I think you’d be stretching things to say adding PV panels reduces the load to zero. I have a 45 degree pitch roof and I get snow build up some times especially if we get freezing rain before the snow. Also if you have an asphalt shingle roof you can create an unbalanced load with snow sliding off the south side and sticking on the north side. Most engineers take this into consideration too. Thanks, Will __ Will White Regional Field Operations Manager – New England Real Goods Solar 64 Main St. Montpelier, VT 05602 Tel: (802) 223-7804 Cell: (802) 234-3167 www.realgoodssolar.comhttp://www.realgoodssolar.com/ From: re-wrenches-boun...@lists.re-wrenches.orgmailto:re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of Gary Bassett Sent: Tuesday, February 19, 2013 1:48 PM To: re-wrenches@lists.re-wrenches.orgmailto:re-wrenches@lists.re-wrenches.org Subject: [RE-wrenches] Snow loads Has anyone in the snow belt areas have any luck with convincing their local building inspectors that the snow melts or slides from panels, much like a metal roof only better. Thus your snow load would be reduced to zero where the panels have been installed. Gary ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.orgmailto: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.htmhttp://www.re-wrenches.org/etiquette.htm Check out participant bios: www.members.re-wrenches.orghttp://www.members.re-wrenches.org/ ___ List sponsored by Home Power magazine List Address: RE-wrenches@lists.re-wrenches.orgmailto:RE-wrenches@lists.re-wrenches.org Options settings:
[RE-wrenches] Remote Sunny boy Monitoring
Friends: Thanks for the responses to my question. Here is what I have learned: The main problem is that the Sunny Boy is remote from the house and there is no signal conduit. There are any number of monitors that can hard wire to the Sunny Boy, usually with an RS485 connection. Without a hardwire path that solution is not so easy. Apparently I need to asses the viability of a wireless RS485 system. I am wondering: 1. Do I understand the above scenario correctly? 2. Do any of you have any experience with wireless 485 systems? Thanks again for all of the help. William Miller Miller Solar Voice :805-438-5600 email: will...@millersolar.com http://millersolar.com License No. C-10-773985 ___ List sponsored by Home Power magazine List Address: RE-wrenches@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
Re: [RE-wrenches] Remote Sunny boy Monitoring
There is a company called Digi.com. they make a wireless bridge for the RS-485 protocol. Needs to be line of sight, but it will travel about 1000'. They are familiar with installers using their radios to communicate with our inverters, set up is pretty straight forward. I am looking for a part number. I have a couple of systems from my install days with these being used. I like Ryan's solution as well. SMA America, LLC Steve Jefferson Supervisor, Service Line 6020 West Oaks Blvd, Suite 300 Rocklin, CA 95765 - 3714 U.S.A. Tel: +1 916 625 0870 Fax: +1 916 624-2445 Service Line +1 877 697 6283 (Toll Free) Email: steve.jeffer...@sma-america.com www.SMA-America.comhttp://www.sma-america.com/ This email and any attachments thereto may contain SMA America, LLC confidential, privileged and private material for the sole use of the intended recipient. Any review, copying, or distribution of this email (or any attachments thereto) by others is strictly prohibited. If you are not the intended recipient, please contact the sender immediately and permanently delete the original and any copies of this email and any attachments thereto. Thank you. ___ List sponsored by Home Power magazine List Address: RE-wrenches@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
Re: [RE-wrenches] Remote Sunny boy Monitoring
Steve, Ryan: I don't quite have line of sight. There is the brow of a hill... I will look to see if any of the wireless solutions will handle this scenario. Wm At 12:57 PM 2/22/2013, Steve Jefferson wrote: Content-Language: en-US Content-Type: multipart/alternative; boundary=_000_41FE255D65D554478C3B17F3EB5410EF5768618DSVRUSEXMBX01sma_ There is a company called Digi.com. they make a wireless bridge for the RS-485 protocol. Needs to be line of sight, but it will travel about 1000'. They are familiar with installers using their radios to communicate with our inverters, set up is pretty straight forward. I am looking for a part number. I have a couple of systems from my install days with these being used. I like Ryan's solution as well. ___ List sponsored by Home Power magazine List Address: RE-wrenches@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
Re: [RE-wrenches] Remote Sunny boy Monitoring
If that is the case, there are some Ethernet bridges that will work. Depending on distance, you would need to buy a set with either adjustable power or know the exact range. I have a security camera set up I used a set on, had adjustable power setting. Works great. Adjusting the power adds bend to the signal. You might want to give digi a call, they have many solutions for things like this. SMA America, LLC Steve Jefferson Supervisor, Service Line 6020 West Oaks Blvd, Suite 300 Rocklin, CA 95765 - 3714 U.S.A. Tel: +1 916 625 0870 Fax: +1 916 624-2445 Service Line +1 877 697 6283 (Toll Free) Email: steve.jeffer...@sma-america.com www.SMA-America.com This email and any attachments thereto may contain SMA America, LLC confidential, privileged and private material for the sole use of the intended recipient. Any review, copying, or distribution of this email (or any attachments thereto) by others is strictly prohibited. If you are not the intended recipient, please contact the sender immediately and permanently delete the original and any copies of this email and any attachments thereto. Thank you. -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org] On Behalf Of William Miller Sent: Friday, February 22, 2013 1:35 PM To: RE-wrenches Subject: Re: [RE-wrenches] Remote Sunny boy Monitoring Steve, Ryan: I don't quite have line of sight. There is the brow of a hill... I will look to see if any of the wireless solutions will handle this scenario. Wm ___ List sponsored by Home Power magazine List Address: RE-wrenches@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
Re: [RE-wrenches] Remote Sunny boy Monitoring
i have set up wireless bridges for ip to remote locations and my experience with this has me leaning towards no dice william. these links run in the 2.3 gHz and up range which is line-of-sight only. trees will even attenuate the signal, so total blockage with the earth looks grim. have a great weekend everyone! todd On Friday, February 22, 2013 1:34pm, William Miller will...@millersolar.com said: Steve, Ryan: I don't quite have line of sight. There is the brow of a hill... I will look to see if any of the wireless solutions will handle this scenario. Wm At 12:57 PM 2/22/2013, Steve Jefferson wrote: Content-Language: en-US Content-Type: multipart/alternative; boundary=_000_41FE255D65D554478C3B17F3EB5410EF5768618DSVRUSEXMBX01sma_ There is a company called Digi.com. they make a wireless bridge for the RS-485 protocol. Needs to be line of sight, but it will travel about 1000'. They are familiar with installers using their radios to communicate with our inverters, set up is pretty straight forward. I am looking for a part number. I have a couple of systems from my install days with these being used. I like Ryan's solution as well. ___ List sponsored by Home Power magazine List Address: RE-wrenches@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 Sent from Finest Planet WebMail. ___ List sponsored by Home Power magazine List Address: RE-wrenches@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
Re: [RE-wrenches] Remote Sunny boy Monitoring
Hi William, I have successfully used this product below on a few installs without line of sight, trees, hills, etc in the way approx 1 km span doing exactly what you are asking for - wireless RS485. It costs more than WiFi bridges, but it also works! http://www.bb-elec.com/Products/Wireless-Cellular/Radio-Modems/Industrial-Grade-Radio-Modems.aspx Specifically, the LR-KIT, at 900MHz is better for marginal sites, coupled with external antennas and quality cable. Don't skimp! I used a Yagi antenna on the webbox side to transmit, with an omni antenna on the receiving end. Line them up as best you can and spend a bit of time adjusting until there's a signal. Once we got the units talking it's been 100% uptime for at least 2 years now. This company has all sorts of neat network products that I have been using for over a decade. Amazingly solid industrial quality gear. I believe they have a wireless AC relay solution as well I saw people asking in another thread. I never ended up deploying, but they had an easy off-the-shelf solution for a wireless gen start signal retrofit where pulling cable wasn't going to happen. Kevin -Original Message- From: re-wrenches-boun...@lists.re-wrenches.org [mailto:re-wrenches-boun...@lists.re-wrenches.org]On Behalf Of William Miller Sent: February 22, 2013 10:20 AM To: RE-wrenches Subject: [RE-wrenches] Remote Sunny boy Monitoring Friends: Thanks for the responses to my question. Here is what I have learned: The main problem is that the Sunny Boy is remote from the house and there is no signal conduit. There are any number of monitors that can hard wire to the Sunny Boy, usually with an RS485 connection. Without a hardwire path that solution is not so easy. Apparently I need to asses the viability of a wireless RS485 system. I am wondering: 1. Do I understand the above scenario correctly? 2. Do any of you have any experience with wireless 485 systems? Thanks again for all of the help. William Miller Miller Solar Voice :805-438-5600 email: will...@millersolar.com http://millersolar.com License No. C-10-773985 ___ List sponsored by Home Power magazine List Address: RE-wrenches@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 ___ List sponsored by Home Power magazine List Address: RE-wrenches@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
Re: [RE-wrenches] Electric car chargers
William, I found this on Wikipedia: Level Original definition[195]Coulomb Technologies' definition[196] Connectors Level 1 AC energy to the vehicle's on-board charger; from the most common U.S. grounded household receptacle, commonly referred to as a 120 volt outlet. 120 V AC; 16 A (= 1.92 kW) SAE J1772 (16.8 kW), NEMA 5-15 Level 2 AC energy to the vehicle's on-board charger;208 - 240 volt, single phase. The maximum current specified is 32 amps (continuous) with a branch circuit breaker rated at 40 amps. Maximum continuous input power is specified as 7.68 kW (= 240V x 32A*). 208-240 V AC; 12 A - 80 A (= 2.5 - 19.2 kW) SAE J1772 (16.8 kW), IEC 62196 (44 kW), Magne Charge (Obsolete), Avcon, IEC 60309 16 A (3.8 kW) IEC 62198-2 Type2 same as VDE-AR-E 2623-2-2, also known as the Mennekes connector (43.5 kW)IEC 62198-2 Type3 also known as Scame Level 3 DC energy from an off-board charger; there is no minimum energy requirement but the maximum current specified is 400 amps and 240 kW continuous power supplied. very high voltages (300-600 V DC); very high currents (hundreds of Amperes) Magne Charge (Obsolete) CHΛdeMO (62.5 kW), SAE J1772 Combo, IEC 62196 Mennekes Combo .* or potentially 208V x 37A, out of the strict specification but within circuit breaker and connector/cable power limits. Alternatively, this voltage would impose a lower power rating of 6.7 kW at 32A. Is this what you're looking for? My Nissan Leaf came with a Level 1 adapter cord to plug into any standard 120v outlet. I installed a Level 2 charger in my garage, 240v/30 amp. The car also has a Level 3 charging port that I've used several times at public Level 3 charging stations. Randy Brooks Brooks Solar, Inc. Solar Power for People 140 Columbia View Chelan, WA 98816 509-682-9646 ra...@brookssolar.com www.BrooksSolar.com On Feb 22, 2013, at 4:29 PM, William Miller will...@millersolar.com wrote: Friends: I would not bother this group with a question I could easily answer for myself with a little research. I thought I could find the answer to this question on line but it has been very elusive: Does anyone know the ratings for the available high power electric car charger? Thanks in advance. William Miller Miller Solar Voice :805-438-5600 email: will...@millersolar.com http://millersolar.com License No. C-10-773985 ___ List sponsored by Home Power magazine List Address: RE-wrenches@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 ___ List sponsored by Home Power magazine List Address: RE-wrenches@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
[RE-wrenches] Electric car chargers
William, I would have to concur with Randy's chart pretty much. A couple months a go we bought a 2012 Toyota RAV4 EV. I had just recently completed an upgrade system here (4.5KW PV, Classic, 84 KW of Rolls batts and a Radian). We are off-grid. The research I did before purchasing our charger is the currently available chargers max at 7.7 KW. Almost all of the level II chargers (240 volt) charge at one rate...I was able to find a charger made by Siemens that has an adjustable charge rate which has proved very valuable being off-grid (EG: varying solar resource, charging window, departure time, battery temp, SOC, etc). I'm not sure if there is any effort to market a residential charger that will put out more than 7.7KW. Bill Feather River Solar Electric Taylorsville, CA - Original Message - From: William Miller will...@millersolar.com To: RE-wrenches re-wrenches@lists.re-wrenches.org Sent: Friday, February 22, 2013 4:29 PM Subject: [RE-wrenches] Electric car chargers Friends: I would not bother this group with a question I could easily answer for myself with a little research. I thought I could find the answer to this question on line but it has been very elusive: Does anyone know the ratings for the available high power electric car charger? Thanks in advance. William Miller Miller Solar Voice :805-438-5600 email: will...@millersolar.com http://millersolar.com License No. C-10-773985 ___ List sponsored by Home Power magazine List Address: RE-wrenches@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 ___ List sponsored by Home Power magazine List Address: RE-wrenches@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
