Announcement

Collapse
No announcement yet.

Small to Large

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • Small to Large

    I have been reading about offgrid solar systems for a few years now and I thought that I would have my first system up this year but got hit by Maria here in Puerto Rico. Now I am getting more serious about it. What I would like to start with is emergency 2000 W system but with the ability to upgrade to between 20K to 25K watts. So would like to know comments on what inverters, chargers, batteries, etc which may have something to do with handling higher wattage in the next couple of years.

    Thanks in advance for your inputs.

  • #2
    You may design a system for any size. However two sizes require two different designs, and different equipment.

    It is extremely difficult to 'grow' a system.
    4400w, Midnite Classic 150 charge-controller.

    Comment


    • #3
      As organic farmer states growing a solar / battery system usually means throwing away most of the equipment purchased for a small system and getting the right equipment for the larger one. The biggest cost is the battery system. You should never add new batteries to an old set. A system with different aged batteries will result in the new ones losing life sooner because the old ones hurt them.

      Depending on where you live a solar / battery system that can generate 1kWh may cost somewhere between $1500 and $2000. So if you plan on using 20kWh a day your costs may be around $30,000 to $40,000.

      It is best to decide what you need for the future and build a system to meet it now then to grow it.

      Comment


      • #4
        From the couple of inputs here, perhaps may be better to build small systems in the house as needed. Such as one for my emergency needs with a fridge, couple of fans and small led tv with a few things like the satellite receiver and android tv . This module may be the strongest because the fridge runs all day long.

        Would this be more realistic than adding to a present system? Later I can add other modules for bedrooms, kitchen and baths etc which may not use so much electricity.

        Keep the comments coming.

        Comment


        • #5
          Creating "new" systems for new loads could be a better path. Just don't go with low wattage panels or PWM type charge controllers.

          The cost of low wattage "battery" or "12 volt" panel seem to have a higher cost per watt then "grid type" or "34 volt" panels. Also it is better to have the same type of panel for all systems in case you need decide to combine them some time in the future.

          PWM charge controllers connected to more than 200 watts of panels will result in a loss of 33% of charging amps.

          MPPT charge controllers (while more expensive) will convert close to 100% of the panel wattage to charging amps and is a better way to go.

          Comment


          • #6
            Originally posted by papitohead View Post
            I have been reading about offgrid solar systems for a few years now and I thought that I would have my first system up this year but got hit by Maria here in Puerto Rico. Now I am getting more serious about it. What I would like to start with is emergency 2000 W system but with the ability to upgrade to between 20K to 25K watts. So would like to know comments on what inverters, chargers, batteries, etc which may have something to do with handling higher wattage in the next couple of years.

            Thanks in advance for your inputs.
            Browse the systems on this web page for some ideas ...
            https://www.bluepacificsolar.com/eme...kup-power.html
            Plus the cost of the optional battery bank

            I think you may need a Hybrid System ...
            a) Grid Tie to sell your PV Power every day when the grid is up
            b) Off-Grid with battery backup and a DC-to-AC Inverter to operate Critical Loads only.

            Also, check out the Tesla Power Wall = a Li-Ion Battery Bank + DC-to-AC Inverter ( add PV Array )
            https://www.tesla.com/powerwall

            Comment


            • #7
              Originally posted by NEOH View Post

              Browse the systems on this web page for some ideas ...
              https://www.bluepacificsolar.com/eme...kup-power.html
              Plus the cost of the optional battery bank

              I think you may need a Hybrid System ...
              a) Grid Tie to sell your PV Power every day when the grid is up
              b) Off-Grid with battery backup and a DC-to-AC Inverter to operate Critical Loads only.

              Also, check out the Tesla Power Wall = a Li-Ion Battery Bank + DC-to-AC Inverter ( add PV Array )
              https://www.tesla.com/powerwall
              I would fully support and encourage anyone to first go with a grid tie system first.

              But the OP is in Puerto Rico where IMO the grid is almost none existent and unreliable.

              So while off grid systems are not cost effective building a hybrid system may also be a waste of money where the OP lives because if you can't rely on the grid being there most of the time then why even build something that connects to it.

              Comment


              • #8
                Originally posted by SunEagle View Post

                I would fully support and encourage anyone to first go with a grid tie system first.

                But the OP is in Puerto Rico where IMO the grid is almost none existent and unreliable.

                So while off grid systems are not cost effective building a hybrid system may also be a waste of money where the OP lives because if you can't rely on the grid being there most of the time then why even build something that connects to it.
                You are right SunEagle. Our gird system is so far outdated that this is the reason I want to go offgrid. Also the price for electricity in PR is very high. I am retired and almost 72 years old and I hate to just sit and do nothing. I have always been very active and love doing projects to keep me from getting bored. Still, I think would be better for me to power the most needed things first and then later as I will be gaining knowledge, I will be adding in modules which will not need to be upgraded in the future.

                Comment


                • #9
                  The AC Grid in Puerto Rico is being renovated, not just repaired.
                  Diesel Generators, Solar Arrays, Wind Turbines & Battery Banks are forming micro-grids = higher reliability.
                  I did not say "high reliability", just higher reliability.
                  The average outage in Puerto ( prior to the hurricane ) was only 4 - 5 times worse than the average outage on the US mainland.
                  The average in the USA is two (2) outages per year, lasting an average two (2) hours each incident.
                  So, does 4 - 5 times worse justify pure off-grid, or is hybrid better when power is ON for 355 of 365 days (avg)?
                  Of course, certain locations in Puerto Rico ( or even the US mainland ) can be worse, much worse.
                  On Nov 9th, a recently repaired main high voltage line failed again, dropping powered homes from 40% ON to 18% ON, it was fixed the next day.
                  Time will tell if there will be an increase in reliability or not ...

                  Comment


                  • #10
                    Originally posted by NEOH View Post
                    The AC Grid in Puerto Rico is being renovated, not just repaired.
                    Diesel Generators, Solar Arrays, Wind Turbines & Battery Banks are forming micro-grids = higher reliability.
                    I did not say "high reliability", just higher reliability.
                    The average outage in Puerto ( prior to the hurricane ) was only 4 - 5 times worse than the average outage on the US mainland.
                    The average in the USA is two (2) outages per year, lasting an average two (2) hours each incident.
                    So, does 4 - 5 times worse justify pure off-grid, or is hybrid better when power is ON for 355 of 365 days (avg)?
                    Of course, certain locations in Puerto Rico ( or even the US mainland ) can be worse, much worse.
                    On Nov 9th, a recently repaired main high voltage line failed again, dropping powered homes from 40% ON to 18% ON, it was fixed the next day.
                    Time will tell if there will be an increase in reliability or not ...
                    Well maybe the OP can start out with a small off grid system for his critical loads and then install a larger hybrid grid tie system that gets him the best of both worlds.

                    Comment


                    • #11
                      Hi Papitohead,

                      I am very new to Solar energy and new to this forum, so I'm sure others can correct my thinking. I just installed a 2.5kw Off-Grid system at my home. System includes :
                      - 4 L16 435ah batteries at 24v
                      - 9 panel solar array.

                      I have had it up and running 1 month now as an off-grid / grid-support system. Part of my house is still on the AC Line (Air conditioning, washer, dryer) and most of my house is off-grid. The off-grid system runs 24 / 7 and includes
                      - every led light in my house
                      - TV /modem /printer /clocks
                      - most receptacles in the house (not coffee pot, microwave)
                      - full size side by side fridge (2007 energy star ratings)
                      - 120v deep well pump
                      - and excess power generated from the array is set up to power the bottom half of my water heater with a 750w element 120v (that is a whole other story)

                      I have 1 full day of autonomy if I manage my loads. I never discharge more than 32% (usually less) on any given night in a month and am fully charging the batteries every day when there is decent weather. Can also charge with ac line power which I do once a week to insure batteries are getting fully charged.

                      I believe this to be a good starter system. And - might be wrong - but I believe it could grow it if I wanted to. But u must plan that growth and pay for it up front. Here's what I did.

                      I wanted... And I highly suggest buying all equipment that is rated UL 1741. This is home grade UL certified and is suitable for in home use and wiring. Down side, it will cost you. Up side, Reliability and safety.

                      I stated with 9 panels at 285 watts to a single Midnite classic 150 mppt charge controller. At 2.5kw and 24v the CC is maxed out... BUT... because higher end CCs allow for the use of more than one CC I could make the array larger later by adding another CC and more panels. Midnite solar has a "follow me" feature that let's 2 CCs work together.

                      Then I bought an over sized Inverter. The Conext SW 4024 at 4000 watts was over twice as big as I needed ... but it's "resting" state drew no more watts than the smaller SW 2024 (resting it draws 35-40 watts). The SW inverters are a split 120v so they can be used for 240v applications having an L1 and L2 ... And if needed ... this inverter can be stacked, so I can add another one of same size and brand. My Inverter is also a charger. So if there is no sun I can charge from the AC Line.

                      As noted, batteries would be my biggest limitation to growth. At 435ah my battery bank is small and does not allow for much autonomy, but is adequate for my needs as I can switch on and off the various circuits that are on the solar system (on and off from solar to AC line) thru a 6 circuit solar or line transfer switch and I also have the option for a Gen back up that could also power the Inverter/Charger. My plan is to add 4 more batteries in January - so that would mean my existing batteries would have been in service for 3 months at that point. So I would either 1.) just add the new and "old" batteries together, Or 2.) put the older ones on a trickle charge, and use the new ones for 3 months until they are all 8 at the same age. I believe 870ah would give me about 2.5 days of autonomy with proper power management.

                      So I think - and under stand I really don't know - but I think I could grow this system if I wanted to. Right now the only reason I really want to do that is for more excess power for my dump load to heat more water. So that will mean another CC and more panels, but would not necessarily mean more batteries.

                      But I would say, if you are going to do it ... dont do it on the cheap. I have just under 7k US dollar in the system. But I have really enjoyed the project.
                      Last edited by Matrix; 11-15-2017, 09:04 AM.

                      Comment


                      • #12
                        Originally posted by Matrix View Post
                        Hi Papitohead,

                        I am very new to Solar energy and new to this forum, so I'm sure others can correct my thinking. I just installed a 2.5kw Off-Grid system at my home. System includes :
                        - 4 L16 435ah batteries at 24v
                        - 9 panel solar array.

                        I have had it up and running 1 month now as an off-grid / grid-support system. Part of my house is still on the AC Line (Air conditioning, washer, dryer) and most of my house is off-grid. The off-grid system runs 24 / 7 and includes
                        - every led light in my house
                        - TV /modem /printer /clocks
                        - most receptacles in the house (not coffee pot, microwave)
                        - full size side by side fridge (2007 energy star ratings)
                        - 120v deep well pump
                        - and excess power generated from the array is set up to power the bottom half of my water heater with a 750w element 120v (that is a whole other story)

                        I have 1 full day of autonomy if I manage my loads. I never discharge more than 32% (usually less) on any given night in a month and am fully charging the batteries every day when there is decent weather. Can also charge with ac line power which I do once a week to insure batteries are getting fully charged.

                        I believe this to be a good starter system. And - might be wrong - but I believe it could grow it if I wanted to. But u must plan that growth and pay for it up front. Here's what I did.

                        I wanted... And I highly suggest buying all equipment that is rated UL 1741. This is home grade UL certified and is suitable for in home use and wiring. Down side, it will cost you. Up side, Reliability and safety.

                        I stated with 9 panels at 285 watts to a single Midnite classic 150 mppt charge controller. At 2.5kw and 24v the CC is maxed out... BUT... because higher end CCs allow for the use of more than one CC I could make the array larger later by adding another CC and more panels. Midnite solar has a "follow me" feature that let's 2 CCs work together.

                        Then I bought an over sized Inverter. The Conext SW 4024 at 4000 watts was over twice as big as I needed ... but it's "resting" state drew no more watts than the smaller SW 2024 (resting it draws 35-40 watts). The SW inverters are a split 120v so they can be used for 240v applications having an L1 and L2 ... And if needed ... this inverter can be stacked, so I can add another one of same size and brand. My Inverter is also a charger. So if there is no sun I can charge from the AC Line.

                        As noted, batteries would be my biggest limitation to growth. At 435ah my battery bank is small and does not allow for much autonomy, but is adequate for my needs as I can switch on and off the various circuits that are on the solar system (on and off from solar to AC line) thru a 6 circuit solar or line transfer switch and I also have the option for a Gen back up that could also power the Inverter/Charger. My plan is to add 4 more batteries in January - so that would mean my existing batteries would have been in service for 3 months at that point. So I would either 1.) just add the new and "old" batteries together, Or 2.) put the older ones on a trickle charge, and use the new ones for 3 months until they are all 8 at the same age. I believe 870ah would give me about 2.5 days of autonomy with proper power management.

                        So I think - and under stand I really don't know - but I think I could grow this system if I wanted to. Right now the only reason I really want to do that is for more excess power for my dump load to heat more water. So that will mean another CC and more panels, but would not necessarily mean more batteries.

                        But I would say, if you are going to do it ... dont do it on the cheap. I have just under 7k US dollar in the system. But I have really enjoyed the project.
                        Thanks for your post. Very interesting. Perhaps you would like to post photos of your system and also a link to where you got it.

                        Comment


                        • #13
                          I am back again. We lost power again for a couple of days. Still studying this and am planning on investing on a system in early spring because we are going to spend the holidays in Colombia where I have a liitle farm.

                          Comment


                          • #14
                            I'll try and post up some pics tonight. Not sure if the forum allows external links. I tried to post a link to the Financials of REC a few weeks ago and my post kept getting kicked out for the links.

                            Comment


                            • #15
                              Originally posted by SunEagle View Post
                              So while off grid systems are not cost effective building a hybrid system may also be a waste of money where the OP lives because if you can't rely on the grid being there most of the time then why even build something that connects to it.
                              Depends where he is. If he's in a place where the grid will come back in six months, and will be working for even 50% of the time, it's worth it for the savings in battery costs.

                              Comment

                              Working...
                              X