Hi Mac Thanks for mentioning this, I’ve wondered about it a lot. Maybe someone who’s a motor or electronics expert can chime in about what potential damage can occur. Electronics, motors, VFD’s, are used to seeing voltage +/- by a fair amount, but frequency is rarely off by more than a fraction of a percent.
If the frequency shift is doing nothing more than turning the GT inverter off ( no stepped regulation) then why do that vs relay? It still makes for a 5 minute delay on restart, correct? Thx Jay > On Feb 15, 2018, at 7:48 AM, Mac Lewis <maclew...@gmail.com> wrote: > > Hi Wrenches, > > I just wanted to report that some electronics will fail and burn up during > frequency shift. We have an off-grid Sunny Island system (60-62 Hz operating > frequency) and we experienced sensitive electronics burning up during these > events. Its been too long since this happened to tell you exactly what > burned up. I think it was some HVAC controls. > > If its possible, I'd suggest a relay that opens up the grid-tie inverter as > opposed to waiting until frequency shift is necessary. A well-specified > relay can be highly reliable and not very expensive. > > Thanks > >> On Tue, Feb 13, 2018 at 11:26 AM, Glenn Burt <glenn.b...@glbcc.com> wrote: >> An installer I have been working with here in southern VT has also >> repeatedly applied to become an installer with Tesla for powerwalls with no >> response. >> I cannot in good conscience recommend their products based on their history >> and unresponsiveness in our area. >> They may be great for Puerto Rico, and now Australia, but have currently >> rated a thumbs down here. We are happy with the sonnen product, delivery and >> support. >> >> Glenn >> Sent from my 'smart' phone so please excuse spelling and typographical >> errors. >> >> ------ Original message------ >> From: Dave Tedeyan >> Date: Tue, Feb 13, 2018 11:35 AM >> To: RE-wrenches; >> Cc: >> Subject:Re: [RE-wrenches] experience with the Tesla Powerwall >> >> I think that this may have come up before, but I do not remember there being >> a resolution: >> Do you guys have any tips on becoming a Tesla dealer? We have people ask >> about it all the time, but we have not been able to get Tesla to respond. We >> have installed Sonnen, which is also a great system, but the up front >> expense scares many people away. We are located in upstate NY which may have >> something to do with it. >> >> Cheers, >> Dave >> >> >> -- >> >> Dave Tedeyan >> Senior Engineer >> >> Taitem Engineering, PC >> 10 Verizon Lane, Lansing, NY 14882 >> Voice: (607) 930-3481 x6 >> www.taitem.com >> >>> On Tue, Feb 13, 2018 at 10:36 AM, August Goers <aug...@luminalt.com> wrote: >>> Marco, >>> >>> Thanks for sharing, it is good to hear details from an installer who is >>> living with a Powerwall. We starting selling the Powerwall 2 in 2017 and >>> have worked up a large pipeline. We have about 20 installed so far, but are >>> still waiting on utility permission to operate which is taking a long time. >>> We have spent a good deal of time commissioning and testing each system. >>> For the most part, our experience has been good although the commissioning >>> software and internet connectivity features have been buggy. Hopefully >>> those are issues that will be ironed out by Tesla. Otherwise, we've had the >>> systems correctly operate in on-grid and off-grid modes with both Sol >>> aredge and SunPower Equinox AC coupled systems. >>> >>> We installed conventional lead acid battery backup systems for over 10 >>> years and I can confidently say that Tesla's Powerwall and Gateway setup >>> is truly market-disruptive. The design flexibility of the Gateway setup, >>> the small size, minimal labor to install, and performance blow other >>> systems out of the water. I hope that other manufacturers are able to catch >>> up with this type of design. >>> >>> Best, >>> >>> August >>> >>> August Goers >>> >>> Luminalt Energy Corporation >>> >>> o: 415.641.4000 >>> >>> www.luminalt.com >>> >>> >>> >>> >>>> On Sat, Feb 10, 2018 at 12:23 PM, Marco Mangelsdorf <ma...@pvthawaii.com> >>>> wrote: >>>> Aloha Wrenches, >>>> >>>> I thought I'd share my own experiences with the Powerwall as my company is >>>> now launching a program to add PW to existing NEM systems since the vast >>>> majority of them do not have storage which means that if the grid goes >>>> down, so does their PV system. (With the exception of the SMA SB line and >>>> their Secure Power Supply.) >>>> >>>> And no, I'm not a shill or toadie for Tesla. >>>> >>>> marco >>>> >>>> I wanted to walk my own talk. Before we launched adding Powerwall to >>>> existing Net Energy Metered solar electric systems, I wanted to make sure >>>> that what was promised on paper would work in the real world. I added >>>> Powerwall to my NEM system last year and have been monitoring and testing >>>> it during normal grid-on and grid outage modes. And I’m very pleased to >>>> report that Powerwall has performed flawlessly and as expected. >>>> >>>> >>>> >>>> When used in a NEM system, Powerwall is programmed to be in “Backup” mode. >>>> When utility power is on, Powerwall stands ready in a full state of >>>> charge for any power outage. During normal grid-on conditions, my >>>> Powerall takes about .6 kilowatt-hours every other day to stay fully >>>> charged. Over the course of the month, this Powerwall’s electricity >>>> consumption comes to about 9 kWhs or about $3/month at the current HELCO R >>>> rate. >>>> >>>> >>>> >>>> I have turned the utility power off to my home on a number of occasions in >>>> order to experience how Powerwall would perform in a simulated grid >>>> outage. When the grid goes down, my house effectively becomes a >>>> self-generating micro-grid. That is, my photovoltaic system (solar >>>> modules and inverters) and Powerwall (battery storage and integrated >>>> inverter) form a power grid with energy being created and stored and then >>>> consumed by my electric loads. >>>> >>>> >>>> >>>> Several things I noted from my simulated grid outages: >>>> >>>> · I purposefully overloaded Powerwall by turning on my electric >>>> dryer and electric oven at the same time. As expected, since the maximum >>>> output of Powerwall is 5 kilowatts, it shutdown. Meaning that all the >>>> power in my house went off. Within seconds, Powerwall reset itself and >>>> the power came back on, with the dryer and oven having shut down after the >>>> power went off. If power does not come back on after your Powerwall trips >>>> off, you will need to turn off those high-power loads and reset Powerwall >>>> by turning its black on-off switch, located on the right side of the unit, >>>> from on to off and then on again. The important takeaway: during a >>>> utility outage, you will need to be careful as far as operating heavy >>>> electric loads, especially 240 volt appliances both from the perspective >>>> of overloading your Powerwall and rapidly drawing down the battery >>>> capacity, especially at night. >>>> >>>> · The magic of frequency shifting. Without getting into too much >>>> techno-talk, this is the story of frequency shifting. Normal utility >>>> frequency is 60 hertz (Hz). PV inverters require the utility frequency to >>>> be at or near 60 Hz in order to operate. During a grid outage, Powerwall >>>> effectively establishes grid quality power (120/240 volts at 60 Hz), >>>> allowing a micro grid to operate with solar providing power to your house >>>> loads (during daylight hours) and charge Powerwall as needed. During the >>>> day with the loads being met by your PV system and Powerwall being at or >>>> near full state of charge (97-100 percent), Powerwall will shift the >>>> frequency from 60 to 66 Hz in order to turn off the PV inverter(s). That >>>> is, the PV inverter(s) see the frequency out of spec and shut down as >>>> they’re expected and required to do. Why? Because with Powerwall at or >>>> near full and the house loads being met, there’s nowhere for any >>>> additional solar generation to go. Powerwall will wait for its the state >>>> of charge to drop below 96-97 percent before shifting the frequency back >>>> to 60 Hz which allows the PV system to restart and generate solar power >>>> again. This frequency shifting can take place repeatedly over the course >>>> of the day depending on load demands, solar potential and Powerwall state >>>> of charge and is perfectly normal and does not damage the PV inverters. >>>> >>>> · 66 Hz and home appliances: when Powerwall is at 66 Hz, some of >>>> your house loads may be affected. What I and other Powerwall owners have >>>> noticed, while not a comprehensive list, can include: electronic clocks >>>> running fast, motors sounding different (microwave, washing machine, >>>> pumps), uninterruptible power sources (UPS) not charging and going into >>>> back-up power mode, appliances having a computer behaving unusually. >>>> >>>> >>>> _______________________________________________ >>>> List sponsored by Redwood Alliance >>>> >>>> List Address: RE-wrenches@lists.re-wrenches.org >>>> >>>> Change listserver email address & settings: >>>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >>>> >>>> List-Archive: >>>> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html >>>> >>>> List rules & etiquette: >>>> www.re-wrenches.org/etiquette.htm >>>> >>>> Check out or update participant bios: >>>> www.members.re-wrenches.org >>>> >>>> >>> >>> >>> _______________________________________________ >>> List sponsored by Redwood Alliance >>> >>> List Address: RE-wrenches@lists.re-wrenches.org >>> >>> Change listserver email address & settings: >>> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >>> >>> List-Archive: >>> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html >>> >>> List rules & etiquette: >>> www.re-wrenches.org/etiquette.htm >>> >>> Check out or update participant bios: >>> www.members.re-wrenches.org >>> >>> >> >> >> _______________________________________________ >> List sponsored by Redwood Alliance >> >> List Address: RE-wrenches@lists.re-wrenches.org >> >> Change listserver email address & settings: >> http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org >> >> List-Archive: >> http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html >> >> List rules & etiquette: >> www.re-wrenches.org/etiquette.htm >> >> Check out or update participant bios: >> www.members.re-wrenches.org >> >> > > > > -- > > > > Mac Lewis > > "Yo solo sé que no sé nada." -Sócrates > > _______________________________________________ > List sponsored by Redwood Alliance > > List Address: RE-wrenches@lists.re-wrenches.org > > Change listserver email address & settings: > http://lists.re-wrenches.org/options.cgi/re-wrenches-re-wrenches.org > > List-Archive: > http://www.mail-archive.com/re-wrenches@lists.re-wrenches.org/maillist.html > > List rules & etiquette: > www.re-wrenches.org/etiquette.htm > > Check out or update participant bios: > www.members.re-wrenches.org >
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