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  • Which system- grid....hybrid? (I'm new)

    I'm more than considering installing a PV system to our house and am new to the system design and recommendation process.

    I've read about various systems such as grid tied, hybrid and understand them somewhat.

    - Our zip code is 19380.
    - We use about 450 kWh per month.
    - Well supplied water (220V 15A)
    - Cooking, hot water heating and clothes dryer are natural gas fired
    - 'Have a Generac 10kW standby generator natural gas fueled (automatic start upon loss of grid power).
    - Our roof exposure is South, roof pitch is 12/12 (45°) the roof is new. Roof area is about 435 sf and with cutting down of a few trees we'd have a total of 603 sf roof area for panels.

    At this point in my life tax rebates aren't a concern and I would do the installation myself.

    That said, the scenario I'd like to plan for (unless it's not practical) PV supplied power with battery backup being able to supply 5 days of grid power loss (no electrical generator) while using reduced power (not using a dishwasher or other heavy power devices) but must be able to supply power to a medium sized refrigerator and freezer. Also, it would be good to be able to have it grid tied so that the PV system can supply our house with power but also feed excess power to the grid.

    It would be nice to hire a solar designer (fee for service) that could specifically address these questions or guide me in reasonable direction. The most I can find on the web are "installers".

    Do you have any recommendations or suggestions or other ideas?

    Thank you,

    Peter


  • #2
    Welcome to the neighborhood.

    The biggest and most common thing new folks who show up here needing more of is education in the basics. This is not, IMO only, a good place to get that. This place is a gap filler.

    Before you buy anything, a good place to get a start on those basics is with a read of "Solar Power Your Home for Dummies", either as a free PDF download or ~ $25 for an updated version at bookstores or Amazon. Then, come back here and ask questions that fill in the knowledge gaps and answer more questions your education will create. Your questions will have more meat on them after the read and other efforts, and the answers you get here will also be better, more focused to your more informed questions and probably have more info in them that may well generate more questions on your part. And so it goes.

    In the meantime and until then, a couple of questions/comments:

    If your annual usage is ~ 450 kWh/month *12 months = 5,400 kWh/yr. and your POwer COmpany (the "POCO") offers net metering, to offset that entire 5,400 kWh/yr. load (which may/may not be the most cost effective solution or choice depending on what you want and what's available to you, and your budget) and given your location and stated roof size, but depending mostly on what your inclination after your education, you may find you'll need something like a 4 STC kW system that covers about 250 - 300 ft.^2 depending on chosen panel and layout.

    Depending array layout, and also depending on any building codes and fire regulations for required setbacks and other permitting issues, you may wind up needing most of that 435 ft.^2 of roof area, but you'll probably be OK. Just don't assume so until you get into preliminary design. See PVWatts for a user friendly modeling tool for non solar folks. Read all the help screens a couple of times and use 10 % for a system loss parameter -something you'll find explained in the help section. Do a few runs and play around and in ~ 20 minutes or so, you'll be on your way.

    NOMB, but with annual usage of 5,400 kWh/yr., which would indicate not a lot of use of high powered appliances unless you're welding stuff in your spare time, why such a big generator ?

    DIY install of PV is a lot more complicated than installing a garage door opener. Some folks who are pretty self reliant have come here after thinking it was a cake walk and left pissed off because they didn't know what was required and found out from someone who suffers fools badly that they bought a lot of the wrong stuff, got in way over their head and wasted a lot wasted a lot of time/$$'s. Other DIYers have done OK, and some others in between. Just sayin. Seems that just because someone can, for example, wire a house, doesn't mean they can do a PV system and not make a dangerous mess of it.

    On battery backup: the 5 days isn't as important as how large in terms of kWh of usage those 5 days will burn through. Battery storage can be pretty expensive and with a generator already on hand, I'd skip the storage for now, or at least until you've done enough research on the solar resource, PV and batteries so your own ignorane on those subjects isn't fertile ground for the solar peddlers to get into your wallet.

    Educate yourself before you spend dime one. You'll have a safer, better, more cost effective and more fit for purpose system.

    Comment


    • #3
      exactly what JPM said
      Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
      || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
      || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

      solar: http://tinyurl.com/LMR-Solar
      gen: http://tinyurl.com/LMR-Lister

      Comment


      • #4
        Originally posted by J.P.M. View Post
        Welcome to the neighborhood.

        The biggest and most common thing new folks who show up here needing more of is education in the basics. This is not, IMO only, a good place to get that. This place is a gap filler.

        Before you buy anything, a good place to get a start on those basics is with a read of "Solar Power Your Home for Dummies", either as a free PDF download or ~ $25 for an updated version at bookstores or Amazon. Then, come back here and ask questions that fill in the knowledge gaps and answer more questions your education will create. Your questions will have more meat on them after the read and other efforts, and the answers you get here will also be better, more focused to your more informed questions and probably have more info in them that may well generate more questions on your part. And so it goes.

        In the meantime and until then, a couple of questions/comments:

        If your annual usage is ~ 450 kWh/month *12 months = 5,400 kWh/yr. and your POwer COmpany (the "POCO") offers net metering, to offset that entire 5,400 kWh/yr. load (which may/may not be the most cost effective solution or choice depending on what you want and what's available to you, and your budget) and given your location and stated roof size, but depending mostly on what your inclination after your education, you may find you'll need something like a 4 STC kW system that covers about 250 - 300 ft.^2 depending on chosen panel and layout.

        Depending array layout, and also depending on any building codes and fire regulations for required setbacks and other permitting issues, you may wind up needing most of that 435 ft.^2 of roof area, but you'll probably be OK. Just don't assume so until you get into preliminary design. See PVWatts for a user friendly modeling tool for non solar folks. Read all the help screens a couple of times and use 10 % for a system loss parameter -something you'll find explained in the help section. Do a few runs and play around and in ~ 20 minutes or so, you'll be on your way.

        NOMB, but with annual usage of 5,400 kWh/yr., which would indicate not a lot of use of high powered appliances unless you're welding stuff in your spare time, why such a big generator ?

        DIY install of PV is a lot more complicated than installing a garage door opener. Some folks who are pretty self reliant have come here after thinking it was a cake walk and left pissed off because they didn't know what was required and found out from someone who suffers fools badly that they bought a lot of the wrong stuff, got in way over their head and wasted a lot wasted a lot of time/$$'s. Other DIYers have done OK, and some others in between. Just sayin. Seems that just because someone can, for example, wire a house, doesn't mean they can do a PV system and not make a dangerous mess of it.

        On battery backup: the 5 days isn't as important as how large in terms of kWh of usage those 5 days will burn through. Battery storage can be pretty expensive and with a generator already on hand, I'd skip the storage for now, or at least until you've done enough research on the solar resource, PV and batteries so your own ignorane on those subjects isn't fertile ground for the solar peddlers to get into your wallet.

        Educate yourself before you spend dime one. You'll have a safer, better, more cost effective and more fit for purpose system.
        Please don't take any of the following as derogatory or belligerent- I'm just trying to get to the point without the usual disclaimer/cautionary nonsense.
        .
        Yes, all of the "educate yourself" stuff was understood beforehand and it's not surprising that many people fail because they think, "oh boy, free electricity....just a little work and we'll not have to pay another bill again...and I'm pretty good working with electricity because, well, honey, remember how I fixed the kitchen light switch?!" At my age I've heard that way too often and do understand, "a fool and his money are soon parted".

        Why generator so big? "Better to oversize than to wish you had" and at the time when I installed it we had an electric stove and electric dryer. If I remember correctly, the 10kW generator would only output 7.5kW using natural gas. I know the output figure was greatly reduced using natural gas.

        As to generator backup as you mentioned before, my concern is "they'll cut off the gas too"...or some other such excuse (I lived through the 1973 bogus oil embargo and remember quite well the tankers anchored off the East coast (New Jersey) until the the price of oil went up).

        As to batteries; the sad commentary of my life is always, "dead batteries" and the price of them is a gigantic concern. Yes, a load analysis would be necessary to determine size....I just gave the "5 days" as a general time length.

        But again, to make it simple for myself, do you fellas have a recommendation for a solar designer? Not some installer- I don't want to waste his time with no intention of using his services- too many people do that sort of stuff and it's deceitful.

        Before any permits or application for a permit certainly contact the local government to tell them what I want to do and see what they won't let me do. The bad part is once a PV array is installed our property taxes are going to go up.

        Lastly, this is supposed to be funny...but true- in my area I've seen several PV installations which have panels installed on a North facing roof with a 6/12 pitch. In talking with the homeowners they have no idea what's on their roof or how much power the array is.

        Peter
        Last edited by pda1; 02-17-2021, 10:02 AM.

        Comment


        • #5
          Originally posted by Mike90250 View Post
          exactly what JPM said
          What does this mean?

          Comment


          • #6
            My question, what is your reason for installing solar? If you want to cancel
            your electric bill, a net metering setup is the way to go. If you want to use a
            lot less gas, your solar will need to be huge, mine heats the house but the
            ground mount is much larger than the roof, and needs the flexibility to point
            the best direction while being accessible for removing snow and some service.

            If you want a backup system, solar is lousy. You would need huge batteries,
            a huge expense needing constant maintenance, and needing a generator
            anyway to prevent their destruction. Solar is most likely to be at minimum
            performance just when you need some backup. Stick with your generator,
            use propane, gasoline, or diesel for additional backup. good luck, Bruce Roe
            Last edited by bcroe; 02-17-2021, 10:31 AM.

            Comment


            • #7
              Originally posted by bcroe View Post
              My question, what is your reason for installing solar? If you want to cancel
              your electric bill, a net metering setup is the way to go. If you want to use a
              lot less gas, your solar will need to be huge, mine heats the house but the
              ground mount is much larger than the roof, and needs the flexibility to point
              the best direction while being accessible for removing snow and some service.

              If you want a backup system, solar is lousy. You would need huge batteries,
              a huge expense needing constant maintenance, and needing a generator
              anyway to prevent their destruction. Solar is most likely to be at minimum
              performance just when you need some backup. Stick with your generator,
              use propane, gasoline, or diesel for additional backup. good luck, Bruce Roe
              Now there's a practical reply for ya! Thanks. I love your comment of "If you want a backup system, solar is lousy". Anyone that's been in this wicked world long enough will perceive that cloud cover can ruin your whole day.

              So...(this is supposed to be funny)....I'm off to Harbor Freight to get one of their plug-and-play solar panel systems. Which might well be the best approach. I've got a 20% off coupon somewhere around here.

              My guess is off gird power generation based on "dooms-day" scenarios is very expensive.

              Again, thank you.

              Peter

              Comment


              • #8
                If money is no object there are plenty of folks that will be glad to take it. When you start out that tax rebates arent important at this time of life while suggesting a self install implies mixed priorities. A Grid tied self install is lot easier to do than a hybrid system. Using panels with integral microinverters is just about as plug and play as you are going to get in the solar game, especially if you don't try to sell SRECs so you don't have to hassle with setting up communications. You have the backup generator so you are not a great subject for hybrid. If you want to avoid using it plan on tripling the upfront cost and have a much larger array.

                You also mention taxes, depending on how your assessor approaches the installation you most likely will pay based on installed cost and a hybrid system is going to cost a bundle more with little return. The only thing a hybrid system will do for you is force your hand on equipment selection and costs and have a far more difficult system to diagnose. The only advantage with a hybrid system is that the grid is going to be incentivizing hybrid installations more generously in the future. This has happened in CA and HI but expect it will take a lot longer to be something in PA. Since you don't care about incentives it then points to a grid tie self install, if you have the skills and equipment and your local authorities let you do the work. I expect someone with the right skills can do a self install, I did 4 of them and only needed an electrical sign off on one to sell SRECS. My guess is unless you are an electrician, the actual tie into the panel may be outside your abilities. There are a few options and they all need to be weighed against what you are installing, what you have for equipment installed and what you need to add. Get the right electrician and he may gladly let you do the grunt work up on the roof and then he does the tie in.

                Education is cheap an I also recommend buying the Dummies book.

                Comment


                • #9
                  Originally posted by peakbagger View Post
                  If money is no object there are plenty of folks that will be glad to take it. When you start out that tax rebates arent important at this time of life while suggesting a self install implies mixed priorities. A Grid tied self install is lot easier to do than a hybrid system. Using panels with integral microinverters is just about as plug and play as you are going to get in the solar game, especially if you don't try to sell SRECs so you don't have to hassle with setting up communications. You have the backup generator so you are not a great subject for hybrid. If you want to avoid using it plan on tripling the upfront cost and have a much larger array.

                  You also mention taxes, depending on how your assessor approaches the installation you most likely will pay based on installed cost and a hybrid system is going to cost a bundle more with little return. The only thing a hybrid system will do for you is force your hand on equipment selection and costs and have a far more difficult system to diagnose. The only advantage with a hybrid system is that the grid is going to be incentivizing hybrid installations more generously in the future. This has happened in CA and HI but expect it will take a lot longer to be something in PA. Since you don't care about incentives it then points to a grid tie self install, if you have the skills and equipment and your local authorities let you do the work. I expect someone with the right skills can do a self install, I did 4 of them and only needed an electrical sign off on one to sell SRECS. My guess is unless you are an electrician, the actual tie into the panel may be outside your abilities. There are a few options and they all need to be weighed against what you are installing, what you have for equipment installed and what you need to add. Get the right electrician and he may gladly let you do the grunt work up on the roof and then he does the tie in.

                  Education is cheap an I also recommend buying the Dummies book.
                  Good advice. Sounds like grid tie is the best option with generator back up.

                  Now to find a designer.

                  Peter

                  Comment


                  • #10
                    Originally posted by pda1 View Post

                    Good advice. Sounds like grid tie is the best option with generator back up.

                    Now to find a designer.

                    Peter
                    By the way that Harbor freight solar system is useless for a grid tie and for that matter even for off grid it is way too little to provide you any power except to light those 2 lights that come with it.

                    Comment


                    • #11
                      Originally posted by SunEagle View Post

                      By the way that Harbor freight solar system is useless for a grid tie and for that matter even for off grid it is way too little to provide you any power except to light those 2 lights that come with it.
                      That was supposed to be funny.

                      Comment


                      • #12
                        If you have a standard layout, there are firms that will design a system for "free" in exchange for buying the equipment from them. I would not advocate this for complex system but if its flat roof grid tied system on new roof they are an option. Sure you may be able to save nickles and dimes by buying surplus panels but lot to be said for single source. You would need to see exactly what the AHJ and utility require for documentation. In most cases you need a stamped mounting design which several racking manufactures provide.and would be handed through the supplier. If you need a stamped electrical design that is more difficult but its depends on the AHJ. If you hire an electrician to do the tie in usually they an AHJ will waive a diagram but it up to the AHJ. The same with the utility, in many cases as long as licensed electrician does the tie in and they know the inverter capacity, they are all set. Others want drawings to spill coffee on.

                        BTW, note I mentioned "new roof". Its generally regarded as a poor idea to install solar on an aged roof that will need to be replaced in 5 or 10 years. As roofs age they do not take well to adding in mounts that are best flashed in. The potential for leaks and damage are higher as the roof ages and good luck ever trying to collect on roof guarantee if you add solar. Ideally you put on new roofing and pay the roofer to install the mounts. Alternatively if its fairly new roof, you can hire the original roofer to to they work or if you have the skills yourself the singles are a lot easier to lift when they are new. I did my roof a few years before solar but I stripped it and put ice and water shield top to bottom so even if the shingles leaked from the mounts I would never see it as the shingles are effectively just protecting the ice and water shield from UV.

                        The one firm that sells kits that I am somewhat familiar with is ALT E stores in Mass. I have bought from them in the past. No doubt there are more firms I am just not familiar with them.

                        The big caveat is once you have a few pallets of equipment dropped off, its too late to decide to hire the work out. Most installation firms only install what they sold and will not touch owner installed equipment. due to the potential hassle if something does not work.

                        I did all my installs including second floor roof solo. It was lot of planning and lot of work a couple of hours a day in the AM when it was light out but before the roof warmed up. Its real easy to get mild heat exhaustion working on roof on a sunny day and that is recipe for fall off the roof.

                        Last edited by peakbagger; 02-17-2021, 11:51 AM.

                        Comment


                        • #13
                          Originally posted by peakbagger View Post
                          If you have a standard layout, there are firms that will design a system for "free" in exchange for buying the equipment from them. I would not advocate this for complex system but if its flat roof grid tied system on new roof they are an option. Sure you may be able to save nickles and dimes by buying surplus panels but lot to be said for single source. You would need to see exactly what the AHJ and utility require for documentation. In most cases you need a stamped mounting design which several racking manufactures provide.and would be handed through the supplier. If you need a stamped electrical design that is more difficult but its depends on the AHJ. If you hire an electrician to do the tie in usually they an AHJ will waive a diagram but it up to the AHJ. The same with the utility, in many cases as long as licensed electrician does the tie in and they know the inverter capacity, they are all set. Others want drawings to spill coffee on.

                          BTW, note I mentioned "new roof". Its generally regarded as a poor idea to install solar on an aged roof that will need to be replaced in 5 or 10 years. As roofs age they do not take well to adding in mounts that are best flashed in. The potential for leaks and damage are higher as the roof ages and good luck ever trying to collect on roof guarantee if you add solar. Ideally you put on new roofing and pay the roofer to install the mounts. Alternatively if its fairly new roof, you can hire the original roofer to to they work or if you have the skills yourself the singles are a lot easier to lift when they are new. I did my roof a few years before solar but I stripped it and put ice and water shield top to bottom so even if the shingles leaked from the mounts I would never see it as the shingles are effectively just protecting the ice and water shield from UV.

                          The one firm that sells kits that I am somewhat familiar with is ALT E stores in Mass. I have bought from them in the past. No doubt there are more firms I am just not familiar with them.

                          The big caveat is once you have a few pallets of equipment dropped off, its too late to decide to hire the work out. Most installation firms only install what they sold and will not touch owner installed equipment. due to the potential hassle if something does not work.

                          I did all my installs including second floor roof solo. It was lot of planning and lot of work a couple of hours a day in the AM when it was light out but before the roof warmed up. Its real easy to get mild heat exhaustion working on roof on a sunny day and that is recipe for fall off the roof.
                          I (which means "me") just replaced the roof last month. I love the warranty on roofing materials- lifetime!...but just on material which is quite similar to paint. I timed the replacement just right- I'll never have to do it again!!! EVER!! Because....I'll be dead before it needs to be replaced. Now that's good planning. Knowing my luck I'll live to be 95 and will complain to the young whipper-snapper roofer who wants to charge $2,000 a square! What?! I only paid $150/square for the material 30 years ago!!!

                          Here's the worse part- the 3 installers I called a few minutes ago, and emailed them as well, have disconnected phones, dead websites or bounced emails. Ah, that's progress!

                          Thanks for the inspiration, regardless.

                          Peter

                          Comment


                          • #14
                            exactly what JPM said

                            Originally posted by pda1 View Post
                            What does this mean?
                            I totally agreed with his summation and didn't want to re type essentially the same thing
                            Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                            || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                            || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

                            solar: http://tinyurl.com/LMR-Solar
                            gen: http://tinyurl.com/LMR-Lister

                            Comment


                            • #15
                              Originally posted by pda1 View Post

                              That was supposed to be funny.
                              Sorry. It is sometimes hard to see if the post was sarcastic or not. I use to use the Comic Sans MS font when I trying to be funny but it has now been disabled.

                              Comment

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