User Tag List

Page 2 of 3 FirstFirst 1 2 3 LastLast
Results 11 to 20 of 27

Thread: AC Coupled Battery Backup Install Questions

  1. #11
    Join Date
    Dec 2012
    Location
    Placerville, CA, USA
    Posts
    20,179
    Mentioned
    3 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Alex-Sun Energy Solutions View Post
    Ahhh I see what you're saying. This is one of the reasons I wanted to be behind the main breaker, if it's just as simple as switching the breaker manually. Enphase must have something up their sleeve but like you and others have said it is likely a transfer switch which the other battery manufacturers rely on as well.

    I've seen the smart breakers, maybe there will be a SMART main that toggles off when there's no voltage. This wouldn't really help all my other clients who have taps above the main because of the 20% rule (can only backfeed 40 amps of solar on 200 amp service). Now that I think of it this may be an inhibitor for this system as well. We will have a total of 80 amps for the solar circuits. I may have to tap it in above the main breaker.

    Back to the drawing board...
    The NEC would never accept any hybrid system which could produce power with no grid input in which safe operation required manual operation of a main breaker for isolation! Unless maybe there were some automatic interlock which disabled island operation when the main breaker was not known to be open.

  2. #12
    Join Date
    May 2011
    Posts
    5,154
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Alex-Sun Energy Solutions View Post
    ... This wouldn't really help all my other clients who have taps above the main because of the 20% rule (can only backfeed 40 amps of solar on 200 amp service). Now that I think of it this may be an inhibitor for this system as well. We will have a total of 80 amps for the solar circuits. I may have to tap it in above the main breaker.

    Back to the drawing board...
    One strategy is to move enough loads out of the MSP (to the critical loads panel) to qualify the MSP under 705.12(B)(2)(3)(c).

  3. #13
    Join Date
    Nov 2015
    Location
    Chelmsford, MA, USA
    Posts
    24
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by jaggedben View Post
    One strategy is to move enough loads out of the MSP (to the critical loads panel) to qualify the MSP under 705.12(B)(2)(3)(c).
    Thanks for rolling onwards with this design. So I google searched this and came back across another posting on this forum which discussed this. Some of you are on that thread as well

    https://forums.mikeholt.com/showthread.php?t=188070

    The details of that are getting a bit over my head. I do have some experience with the NEC, code complaince, etc. But my background is Mechanical Engineering, and my electrical work and code knowledge has all been learned in the field and doing research. I worked on commercial solar design for a year before starting my own company, so residential electrical design was never studied or practiced. I converse with my master electrician, but a lot of this design work is above his skill level. I generate all the 1 and 3 lines for my projects. I think this forum is going to be invaluable as well, so I thank you all tremendously for helping me out. I will definitely post pictures and the finished installation when we get to that point.

    I did some research on feed thru lugs, and came across this schematic by Schneider.

    Name:  SF lugs, FT lugs, SF Breaker.jpg
Views: 94
Size:  106.6 KB

    Is this what you would be referring to? The last two options seem like it would be the same scenario as the 120% rule, basically being able to send 200 amps to the bus from the main breaker, and the 60 or 80 amps from the backfeed solar as well. But the first option, the Sub Feed Lug, seems like it may work in that you would still be protected by 200 amps for the main breaker?


    That being said, I am not really following what simply moving enough loads out of the MSP would accomplish? Is the idea to downsize the main breaker to then be able to backfeed? I thought the 120% rule was based off the main breaker size only, not necessarily the ampacity rating of the bus. (If you downsize to 100 amp main breaker you would be limited to 20 amp backfeed). That wouldn't really make sense from a physics standpoint, as the bus can definitely handle 100 amps + 80 amps solar, but I thought the code was simply 120% main breaker rating, which is 40 amp backfeed for 200 amp main breaker, 20 amp backfeed for 100 amp main breaker.

  4. #14
    Join Date
    May 2011
    Posts
    5,154
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Read the section I quoted again. The 120% rule isn't the only rule anymore. I quoted the 2017 reference since you appear to be in MA.

    As far as the subfeed lugs and breakers, those are all options with their own conderations. But what I had in mind was breakers such as the Homeline 2200BB or the Eaton BJ2200.

  5. #15
    Join Date
    Nov 2015
    Location
    Chelmsford, MA, USA
    Posts
    24
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by jaggedben View Post
    Read the section I quoted again. The 120% rule isn't the only rule anymore. I quoted the 2017 reference since you appear to be in MA.

    As far as the subfeed lugs and breakers, those are all options with their own conderations. But what I had in mind was breakers such as the Homeline 2200BB or the Eaton BJ2200.
    Well that explains it, haven't opened my code book since NEC 2014.

    Looked it up more in depth and thank you for the extra nudge. Here's a link I found explaining the section.

    https://www.jadelearning.com/2014-ne...ions/image3-2/

    I think I understand that code change. Basically move enough loads to the subpanel, and keep the OCPD of the subpanel + remaining loads in the MSP below 200 amps and it is in code.

    What exactly do those breakers you referenced accomplish? I looked them up but am not really following.

    They are also referenced in this thread from this forum, which is pretty much exactly what I am trying to do, install a second 200 amp panel. They also mention going up to a 400 amp meter socket with double lugs. This may be a more cost effective route if I were the electrician, but since I am not I have to consider his time on site. It may be more cost effective for my bottom line to use an expensive breaker and keep it simpler than replacing the meter socket and re-pulling feeders.

    https://forums.mikeholt.com/showthread.php?t=134839

    Hopefully I can understand those breakers a bit more tomorrow after some sleep

  6. #16
    Join Date
    Jan 2018
    Location
    CA
    Posts
    3
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by DeFreitas Enterprises View Post
    At least Enphase isn't as slimy on unveiling then delaying products like TESLA (solar roof, etc).

    Oh no, they're slimy in all kinds of different ways.

    I have PO's open since mid '18 for lots of equipment that haven't been fulfilled. I was forced to move to SolarEdge for all my resi installs because I just couldn't get equipment even on the open market, and there is a very SLIM chance I'll ever go back unless a very narrow set of conditions are met.

    But don't worry, they will offer customers an upgrade program to the same equipment that they can't even fulfill current orders for to fix all the problems they had with M190's.

  7. #17
    Join Date
    May 2011
    Posts
    5,154
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Whalepod View Post
    Oh no, they're slimy in all kinds of different ways.

    I have PO's open since mid '18 for lots of equipment that haven't been fulfilled. I was forced to move to SolarEdge for all my resi installs because I just couldn't get equipment even on the open market, and there is a very SLIM chance I'll ever go back unless a very narrow set of conditions are met.

    But don't worry, they will offer customers an upgrade program to the same equipment that they can't even fulfill current orders for to fix all the problems they had with M190's.
    Having business problems isn't the same as being slimy. Enphase has been open with distributors about what's going on in a way that Tesla never would be. They've been hit with tariffs like many. Also, how is it slimy to offer past customers below-cost replacement of an inferior product 8 years later? What company in any industry have you ever heard of being that generous?
    SolarEdge has its own problems, you'll find out. But there are reasons these companies are at the top of the market right now.

  8. #18
    Join Date
    Nov 2015
    Location
    Chelmsford, MA, USA
    Posts
    24
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by Whalepod View Post
    Oh no, they're slimy in all kinds of different ways.

    I have PO's open since mid '18 for lots of equipment that haven't been fulfilled. I was forced to move to SolarEdge for all my resi installs because I just couldn't get equipment even on the open market, and there is a very SLIM chance I'll ever go back unless a very narrow set of conditions are met.

    But don't worry, they will offer customers an upgrade program to the same equipment that they can't even fulfill current orders for to fix all the problems they had with M190's.
    I ran into a similar issue late in 2018 where the AC combiner boxes and IQ7+ were hard to find. I purchase through the distribution network, not from Enphase directly. My distributors were able to quickly get more supply, and I purchased a couple jobs worth of IQ7+.

    The upgrade program is useless IMO because IQ8 is going to be such a gamechanger that I wouldn't advise someone upgrade to anything before. But the IQ series are a lot more reliable than the older units which my legacy clients have from other installers.

    SolarEdge is a vastly inferior product. The DC to DC optimizers fail just as much, if not more than the microinverters, and you have a central inverter as a single point of failure. There are a couple advantages, you can fit a larger DC system size on a 10 kW AC inverter and remain a simplified interconnection here in MA and receive full net metering credits.

    The StorEdge inverter is also pretty sweet, and allows a much simpler seamless storage solution by pairing the PV and Storage inverter with a Powerwall or LG Chem, etc.

    The extra service of SolarEdge optimizers and single point of failure of a central inverter are why I am die hard Enphase. AC wiring is simpler as well. Now that the EGC and GEC is not part of the trunk cable like it was with the M250 and S280 versions, we have to pull up a #6 THWN for grounding so that kind of blows.

    Quote Originally Posted by jaggedben View Post
    Having business problems isn't the same as being slimy. Enphase has been open with distributors about what's going on in a way that Tesla never would be. They've been hit with tariffs like many. Also, how is it slimy to offer past customers below-cost replacement of an inferior product 8 years later? What company in any industry have you ever heard of being that generous?
    SolarEdge has its own problems, you'll find out. But there are reasons these companies are at the top of the market right now.
    The only correlation between Enphase and TESLA is how Enphase is delaying IQ8. TESLA has unveiled and delayed pretty much every single one of their products. The Solar Roof was the worst of the worst, as I have literally lost multiple clients who are "waiting for the TESLA roof". In the time period they have been waiting, the lucrative SREC program has ended in MA, and soon the 30% tax credit will start stepping down. Instead of buying traditional roof mounted panels, receiving all incentives, paying off within 4-6 years, and then exploring the solar roof in 7-10 years when more economical and ACTUALLY AVAILABLE, these potential clients are now waiting for a product that likely won't be offered in 2014 or 2017 code compliant states for another few years.

    The whole solar roof has been a freaking farce and a joke. I am so disappointed that Elon Musk literally hurt so many of the long tail of installers by promising a product he likely knew would NEVER be able to make it to the market like he promised (Summer of 2017). The fact that he is taking $1000 deposits from homeowners is another farce, as a lot of these people actually need roof replacements. What happens when they desperately need to do have the roof done, but have left a deposit for the solar roof which won't be offered in their state for 2-4 years down the road? What happens is these people then need traditional roofing solution, and have missed out on solar incentives and tax credits they would have had if they didn't "wait for the TESLA roof".

    Anyways, rant over. Will update on this design as we continue through the process.

    Thanks for all your help.

    -Alex

  9. #19
    Join Date
    Oct 2009
    Location
    Austin, TX, USA
    Posts
    10,905
    Mentioned
    1 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by DeFreitas Enterprises View Post
    I ran into a similar issue late in 2018 where the AC combiner boxes ... were hard to find.
    Why would you need specialized AC combiners? We just use regular MLO panels for AC combination.

  10. #20
    Join Date
    Nov 2015
    Location
    Chelmsford, MA, USA
    Posts
    24
    Mentioned
    0 Post(s)
    Tagged
    0 Thread(s)
    Quote Originally Posted by ggunn View Post
    Why would you need specialized AC combiners? We just use regular MLO panels for AC combination.

    The IQ Envoy itself costs like $425-$450, and a MLO panel another $80 or so. The Enphase AC Box ($490-$500) comes with the Envoy pre-wired and space for (4) branch circuits of solar / batteries. It is NEMA 3R rated, and looks pretty sweet as well. It is a plastic enclosure so you have to use grounding lugs for EMT conduit coming in and out but other than that my electrician really likes the panel. They used to only hold (3) 20 amp branch circuits, but I bitched on LinkedIn and they came out with a larger version with an additional branch circuit.

    They basically started advertising that you can install the Enphase batteries right off their AC panel and I informed them they were glossing over the fact that you would drop down to only (2) branch circuits of solar if you used the third circuit for batteries. A couple months later the AC Combiner + was unveiled and now they are on the Combiner 3 which is a smaller unit but still has the (4) branch circuits.

    For this shipping container project I will have (5) branch circuits of solar, and additional circuits for the critical loads and battery backup (Enphase or traditional battery inverter), so I am looking to install a second 200 amp panel for this application. Which led to this thread of how to install a code compliant 200 amp subpanel for the purpose of solar + storage + critical loads.

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •