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Technical questions

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  • Garth & Kim Travis
    Greetings, We are working on a back up system for our home for when the grid is down. We have a 2500 watt inverter that for now is running off my tractor, but
    Message 1 of 20 , Oct 23, 2006
      Greetings,

      We are working on a back up system for our home for when the grid is
      down. We have a 2500 watt inverter that for now is running off my
      tractor, but I would prefer to have a battery bank for it and just
      charge it from my tractor, as a first step. I have our power
      consumption figured at a maximum of 18 KWH per day. How do I
      translate this to watts or amps or VAs so I can size the battery
      bank? If you choose to give me the answer, please be kind and show
      your calculations so we can learn something.

      What is the opinion of AGM batteries? Are they worth the extra
      money? Garth's company has recently started using them, but not for
      long enough for him to form an opinion of them. The companies
      decision is not necessarily a good recommendation.

      Bright Blessings,
      Kim
    • John Miggins
      Kim, here is a handy guide to help size the battery bank and solar system. there needs to be some judgement applied to this as to how many days of back-up you
      Message 2 of 20 , Oct 23, 2006
        Kim, here is a handy guide to help size the battery bank and solar system.
        there needs to be some judgement applied to this as to how many days of back-up you want etc...
         
        AGM batteries are less hassle since they require little maintenance, they will last from 3 to 5 years.  Most large solar system used lead acid, unsealed batteries that allow you to check the state of charge and add water when needed.  They last longer so cost less in the long run.
         
        Rolls Surrette, Trojan or others are a good investment.  If the batteries are just for occasional use for back-up I would then use sealed ones .
         
        Google Solar batteries and you will find more info than you need.
         
         
         
         
        John Miggins
        Harvest Solar & Wind Power
        "renewable solutions to everyday needs"
        www.harvest-energy.com
        Phone/Fax 918-743-2299
        Cell: 918-521-6223
        ----- Original Message -----
        Sent: Monday, October 23, 2006 8:57 AM
        Subject: [hreg] Technical questions

        Greetings,

        We are working on a back up system for our home for when the grid is
        down. We have a 2500 watt inverter that for now is running off my
        tractor, but I would prefer to have a battery bank for it and just
        charge it from my tractor, as a first step. I have our power
        consumption figured at a maximum of 18 KWH per day. How do I
        translate this to watts or amps or VAs so I can size the battery
        bank? If you choose to give me the answer, please be kind and show
        your calculations so we can learn something.

        What is the opinion of AGM batteries? Are they worth the extra
        money? Garth's company has recently started using them, but not for
        long enough for him to form an opinion of them. The companies
        decision is not necessarily a good recommendation.

        Bright Blessings,
        Kim

      • Andrew McCalla
        Kim, We d need to translate your energy consumption to Amp-Hours, which will be based on system voltage. Even better, would be to run your load calcs @
        Message 3 of 20 , Oct 23, 2006
          Kim,

          We'd need to translate your energy consumption to Amp-Hours, which will be
          based on system voltage.

          Even better, would be to run your load calcs @ Amp-Hours.

          AGM's are good but may not be best for the application.

          Tell us more about it (power, voltage, duty cycle of loads, etc.)

          Andrew H. McCalla
          NABCEP Certified Solar PV System Installer (TM)

          Meridian Energy Systems
          2300 S. Lamar, Ste. 107
          Austin, TX 78704

          Voice: (512) 448-0055
          Fax: (512) 448-0045
          www.meridiansolar.com



          -----Original Message-----
          From: hreg@yahoogroups.com [mailto:hreg@yahoogroups.com] On Behalf Of Garth
          & Kim Travis
          Sent: Monday, October 23, 2006 8:58 AM
          To: hreg@yahoogroups.com
          Subject: [hreg] Technical questions

          Greetings,

          We are working on a back up system for our home for when the grid is
          down. We have a 2500 watt inverter that for now is running off my
          tractor, but I would prefer to have a battery bank for it and just
          charge it from my tractor, as a first step. I have our power
          consumption figured at a maximum of 18 KWH per day. How do I
          translate this to watts or amps or VAs so I can size the battery
          bank? If you choose to give me the answer, please be kind and show
          your calculations so we can learn something.

          What is the opinion of AGM batteries? Are they worth the extra
          money? Garth's company has recently started using them, but not for
          long enough for him to form an opinion of them. The companies
          decision is not necessarily a good recommendation.

          Bright Blessings,
          Kim




          Yahoo! Groups Links
        • Paul Archer
          ... This is going to depend on how long you need power. (Also, even though your overall consumption is incredibly low, what are your peak needs?) Let s assume
          Message 4 of 20 , Oct 23, 2006
            > We are working on a back up system for our home for when the grid is
            > down. We have a 2500 watt inverter that for now is running off my
            > tractor, but I would prefer to have a battery bank for it and just
            > charge it from my tractor, as a first step. I have our power
            > consumption figured at a maximum of 18 KWH per day. How do I
            > translate this to watts or amps or VAs so I can size the battery
            > bank? If you choose to give me the answer, please be kind and show
            > your calculations so we can learn something.
            >
            This is going to depend on how long you need power. (Also, even though your
            overall consumption is incredibly low, what are your peak needs?)

            Let's assume you want/need 24 hours of off-grid backup.
            18KWH is 18000 watts for an hour (equivalent). 18000 watts is 12V (I'm
            assuming here, since it's coming off your tractor right now) times 1500A.
            So you should need 1500AH of batteries. Say your batteries are rated for
            50AH each. You'd then need 30 batteries.

            30 batteries x 50AH = 1500AH
            1500AH x 12V = 18000WH (18KWH)

            I think that's right. I'm not an engineer. (I've just been dealing with
            UPS's and batteries a lot for work lately.)


            > What is the opinion of AGM batteries? Are they worth the extra
            > money? Garth's company has recently started using them, but not for
            > long enough for him to form an opinion of them. The companies
            > decision is not necessarily a good recommendation.
            >
            I think AGM was one of the brands the Toshiba UPS rep recommended when we
            talked to him Friday. I've emailed him for a list of recommendations. He had
            also mentioned "refurbished" batteries from UPS's. I'll see what it takes to
            get hold of some of those.

            Paul
          • Paul Archer
            ... This is the response I got from the Toshiba rep: I would recommend a 10 year vrla for cost and size. Use an Enersys brand product. For the lightweight
            Message 5 of 20 , Oct 23, 2006
              9:33am, Paul Archer wrote:

              >> What is the opinion of AGM batteries? Are they worth the extra
              >> money? Garth's company has recently started using them, but not for
              >> long enough for him to form an opinion of them. The companies
              >> decision is not necessarily a good recommendation.
              >>
              > I think AGM was one of the brands the Toshiba UPS rep recommended when we
              > talked to him Friday. I've emailed him for a list of recommendations. He had
              > also mentioned "refurbished" batteries from UPS's. I'll see what it takes to
              > get hold of some of those.
              >

              This is the response I got from the Toshiba rep:

              I would recommend a 10 year vrla for cost and size. Use an Enersys brand
              product. For the lightweight batteries call Arthur Romero at Batteries Plus
              (713) 668-7587 and he should be able to take care of you.


              Paul
            • Jim & Janet
              Kim, if you haven t read the NTREG Yahoo group site lately, you might want to check out recent postings. There will be a number of telcom batteries available
              Message 6 of 20 , Oct 23, 2006
                Kim, if you haven't read the NTREG Yahoo group site lately, you might want to check out recent postings. There will be a number of telcom batteries available soon through a Dallas battery recycling company who has offered them to the RE community before they go public on Ebay.
                 
                Jim Duncan
                North Texas Renewable Energy Inc.
                ntrei@...
                817.917.0527

                ----- Original Message -----
                Sent: Monday, October 23, 2006 8:57 AM
                Subject: [hreg] Technical questions

                Greetings,

                We are working on a back up system for our home for when the grid is
                down. We have a 2500 watt inverter that for now is running off my
                tractor, but I would prefer to have a battery bank for it and just
                charge it from my tractor, as a first step. I have our power
                consumption figured at a maximum of 18 KWH per day. How do I
                translate this to watts or amps or VAs so I can size the battery
                bank? If you choose to give me the answer, please be kind and show
                your calculations so we can learn something.

                What is the opinion of AGM batteries? Are they worth the extra
                money? Garth's company has recently started using them, but not for
                long enough for him to form an opinion of them. The companies
                decision is not necessarily a good recommendation.

                Bright Blessings,
                Kim

              • Andrew McCalla
                Kim, Paul raises some of the many variables which would influence your design. If we could get a comprehensive view of your load profile, then that will
                Message 7 of 20 , Oct 23, 2006
                  Kim,

                  Paul raises some of the many variables which would influence your design.

                  If we could get a comprehensive view of your load profile, then that will
                  answer, or prescribe, most of them.

                  Regarding batteries, there are likewise some conversion inefficiencies which
                  need to be addressed in the sizing, in addition to the matter of autonomy
                  Paul raised.

                  On batteries, AGM (Absorbed Glass Mat) is a cell technology, not a brand,
                  and 30 cells in parallel would be way too many (you only want about 4 max).

                  Andrew H. McCalla
                  NABCEP Certified Solar PV System Installer (TM)

                  Meridian Energy Systems
                  2300 S. Lamar, Ste. 107
                  Austin, TX 78704

                  Voice: (512) 448-0055
                  Fax: (512) 448-0045
                  www.meridiansolar.com



                  -----Original Message-----
                  From: hreg@yahoogroups.com [mailto:hreg@yahoogroups.com] On Behalf Of Paul
                  Archer
                  Sent: Monday, October 23, 2006 9:33 AM
                  To: hreg@yahoogroups.com
                  Subject: Re: [hreg] Technical questions

                  > We are working on a back up system for our home for when the grid is
                  > down. We have a 2500 watt inverter that for now is running off my
                  > tractor, but I would prefer to have a battery bank for it and just
                  > charge it from my tractor, as a first step. I have our power
                  > consumption figured at a maximum of 18 KWH per day. How do I
                  > translate this to watts or amps or VAs so I can size the battery
                  > bank? If you choose to give me the answer, please be kind and show
                  > your calculations so we can learn something.
                  >
                  This is going to depend on how long you need power. (Also, even though your
                  overall consumption is incredibly low, what are your peak needs?)

                  Let's assume you want/need 24 hours of off-grid backup.
                  18KWH is 18000 watts for an hour (equivalent). 18000 watts is 12V (I'm
                  assuming here, since it's coming off your tractor right now) times 1500A.
                  So you should need 1500AH of batteries. Say your batteries are rated for
                  50AH each. You'd then need 30 batteries.

                  30 batteries x 50AH = 1500AH
                  1500AH x 12V = 18000WH (18KWH)

                  I think that's right. I'm not an engineer. (I've just been dealing with
                  UPS's and batteries a lot for work lately.)


                  > What is the opinion of AGM batteries? Are they worth the extra
                  > money? Garth's company has recently started using them, but not for
                  > long enough for him to form an opinion of them. The companies
                  > decision is not necessarily a good recommendation.
                  >
                  I think AGM was one of the brands the Toshiba UPS rep recommended when we
                  talked to him Friday. I've emailed him for a list of recommendations. He had

                  also mentioned "refurbished" batteries from UPS's. I'll see what it takes to

                  get hold of some of those.

                  Paul



                  Yahoo! Groups Links
                • Garth & Kim Travis
                  Greetings, I haven t got a clue how to give you that information. My use of power is rarely the same day to day. If I knew how to get the amp hours, I would
                  Message 8 of 20 , Oct 23, 2006
                    Greetings,
                    I haven't got a clue how to give you that information. My use of
                    power is rarely the same day to day.

                    If I knew how to get the amp hours, I would have the calculation
                    finished as hubby can handle that.

                    I use, on a heavy month about 544 KWH per month or 18 per day. This
                    is from my electric bill.

                    This will be powering a 2500 watt inverter. So maybe figure the
                    inverter running at peak most of the day, as all day would be far
                    more power than I use with the grid.

                    This is not an automated system that runs without supervision. I
                    don't expect all my freezers and fridges to be able to kick on at the
                    same time as my inverter couldn't handle it. This is only running my
                    120 system, my 240 will not operate from it. I will have to wait for
                    my generator to get that stuff running. I will manually be switching
                    circuits until Garth gets a circuit built to do it for me.

                    Bright Blessings,
                    Kim



                    At 09:26 AM 10/23/2006, you wrote:
                    >Kim,
                    >
                    >We'd need to translate your energy consumption to Amp-Hours, which will be
                    >based on system voltage.
                    >
                    >Even better, would be to run your load calcs @ Amp-Hours.
                    >
                    >AGM's are good but may not be best for the application.
                    >
                    >Tell us more about it (power, voltage, duty cycle of loads, etc.)
                    >
                    >Andrew H. McCalla
                    >NABCEP Certified Solar PV System Installer (TM)
                    >
                    >Meridian Energy Systems
                    >2300 S. Lamar, Ste. 107
                    >Austin, TX 78704
                    >
                    >Voice: (512) 448-0055
                    >Fax: (512) 448-0045
                    >www.meridiansolar.com
                    >
                    >
                    >
                    >-----Original Message-----
                    >From: hreg@yahoogroups.com [mailto:hreg@yahoogroups.com] On Behalf Of Garth
                    >& Kim Travis
                    >Sent: Monday, October 23, 2006 8:58 AM
                    >To: hreg@yahoogroups.com
                    >Subject: [hreg] Technical questions
                    >
                    >Greetings,
                    >
                    >We are working on a back up system for our home for when the grid is
                    >down. We have a 2500 watt inverter that for now is running off my
                    >tractor, but I would prefer to have a battery bank for it and just
                    >charge it from my tractor, as a first step. I have our power
                    >consumption figured at a maximum of 18 KWH per day. How do I
                    >translate this to watts or amps or VAs so I can size the battery
                    >bank? If you choose to give me the answer, please be kind and show
                    >your calculations so we can learn something.
                    >
                    >What is the opinion of AGM batteries? Are they worth the extra
                    >money? Garth's company has recently started using them, but not for
                    >long enough for him to form an opinion of them. The companies
                    >decision is not necessarily a good recommendation.
                    >
                    >Bright Blessings,
                    >Kim
                    >
                    >
                    >
                    >
                    >Yahoo! Groups Links
                    >
                    >
                    >
                    >
                    >
                    >
                    >
                    >
                    >Yahoo! Groups Links
                    >
                    >
                    >
                  • Garth & Kim Travis
                    Greetings, This will never be a solar system. Eventually it will be charged by wind or a methane powered generator at which point we will be off grid. Since
                    Message 9 of 20 , Oct 23, 2006
                      Greetings,

                      This will never be a solar system.  Eventually it will be charged by wind or a methane powered generator at which point we will be off grid.  Since I don't as yet have enough animals to create all the methane I need, that will be a while.  For now, I would just like to be able to go for a full day on my batteries and inverter without having to power them.  Running the tractor and charger in a storm is not my first choice of things to do.

                      The chart did not come through with your email.  Will you please send it again?

                      Bright Blessings,
                      Kim




                      At 09:23 AM 10/23/2006, you wrote:
                      X-Yahoo-Newman-Property:groups-email-trad
                      Content-Type: multipart/alternative;
                       boundary="----=_NextPart_001_01B5_01C6F684.D6B993C0"

                      Kim, here is a handy guide to help size the battery bank and solar system.
                      there needs to be some judgement applied to this as to how many days of back-up you want etc...
                       
                      AGM batteries are less hassle since they require little maintenance, they will last from 3 to 5 years.  Most large solar system used lead acid, unsealed batteries that allow you to check the state of charge and add water when needed.  They last longer so cost less in the long run.
                       
                      Rolls Surrette, Trojan or others are a good investment.  If the batteries are just for occasional use for back-up I would then use sealed ones .
                       
                      Google Solar batteries and you will find more info than you need.
                       
                       
                       
                       
                      John Miggins
                      Harvest Solar & Wind Power
                      "renewable solutions to everyday needs"
                      www.harvest-energy.com
                      Phone/Fax 918-743-2299
                      Cell: 918-521-6223
                      ----- Original Message -----
                      From: Garth & Kim Travis
                      To: hreg@yahoogroups.com
                      Sent: Monday, October 23, 2006 8:57 AM
                      Subject: [hreg] Technical questions

                      Greetings,

                      We are working on a back up system for our home for when the grid is
                      down. We have a 2500 watt inverter that for now is running off my
                      tractor, but I would prefer to have a battery bank for it and just
                      charge it from my tractor, as a first step. I have our power
                      consumption figured at a maximum of 18 KWH per day. How do I
                      translate this to watts or amps or VAs so I can size the battery
                      bank? If you choose to give me the answer, please be kind and show
                      your calculations so we can learn something.

                      What is the opinion of AGM batteries? Are they worth the extra
                      money? Garth's company has recently started using them, but not for
                      long enough for him to form an opinion of them. The companies
                      decision is not necessarily a good recommendation.

                      Bright Blessings,
                      Kim

                    • John Miggins
                      go to sunwize.com and download their sizing document, this is by no means an exhaustive or comprehenisive sizing tool just a good place to start good luck.
                      Message 10 of 20 , Oct 23, 2006
                        go to sunwize.com and download their sizing document, this is by no means an exhaustive or comprehenisive sizing tool just a good place to start
                         
                        good luck.
                         
                        kyocerasolar.com also has nice sizing tools
                         
                         
                        John Miggins
                        Harvest Solar & Wind Power
                        "renewable solutions to everyday needs"
                        www.harvest-energy.com
                        Phone/Fax 918-743-2299
                        Cell: 918-521-6223
                        ----- Original Message -----
                        Sent: Monday, October 23, 2006 10:04 AM
                        Subject: Re: [hreg] Technical questions

                        Greetings,

                        This will never be a solar system.  Eventually it will be charged by wind or a methane powered generator at which point we will be off grid.  Since I don't as yet have enough animals to create all the methane I need, that will be a while.  For now, I would just like to be able to go for a full day on my batteries and inverter without having to power them.  Running the tractor and charger in a storm is not my first choice of things to do.

                        The chart did not come through with your email.  Will you please send it again?

                        Bright Blessings,
                        Kim




                        At 09:23 AM 10/23/2006, you wrote:

                        X-Yahoo-Newman- Property: groups-email- trad
                        Content-Type: multipart/alternati ve;
                         boundary="----=_NextPart_ 001_01B5_ 01C6F684. D6B993C0"

                        Kim, here is a handy guide to help size the battery bank and solar system.
                        there needs to be some judgement applied to this as to how many days of back-up you want etc...
                         
                        AGM batteries are less hassle since they require little maintenance, they will last from 3 to 5 years.  Most large solar system used lead acid, unsealed batteries that allow you to check the state of charge and add water when needed.  They last longer so cost less in the long run.
                         
                        Rolls Surrette, Trojan or others are a good investment.  If the batteries are just for occasional use for back-up I would then use sealed ones .
                         
                        Google Solar batteries and you will find more info than you need.
                         
                         
                         
                         
                        John Miggins
                        Harvest Solar & Wind Power
                        "renewable solutions to everyday needs"
                        www.harvest- energy.com
                        Phone/Fax 918-743-2299
                        Cell: 918-521-6223
                        ----- Original Message -----
                        From: Garth & Kim Travis
                        To: hreg@yahoogroups. com
                        Sent: Monday, October 23, 2006 8:57 AM
                        Subject: [hreg] Technical questions

                        Greetings,

                        We are working on a back up system for our home for when the grid is
                        down. We have a 2500 watt inverter that for now is running off my
                        tractor, but I would prefer to have a battery bank for it and just
                        charge it from my tractor, as a first step. I have our power
                        consumption figured at a maximum of 18 KWH per day. How do I
                        translate this to watts or amps or VAs so I can size the battery
                        bank? If you choose to give me the answer, please be kind and show
                        your calculations so we can learn something.

                        What is the opinion of AGM batteries? Are they worth the extra
                        money? Garth's company has recently started using them, but not for
                        long enough for him to form an opinion of them. The companies
                        decision is not necessarily a good recommendation.

                        Bright Blessings,
                        Kim

                      • Garth & Kim Travis
                        Greetings, Thanks, I would be interested in the refurbished batteries. Money is never plentiful. Actually that is from my heaviest month of power consumption
                        Message 11 of 20 , Oct 23, 2006
                          Greetings,

                          Thanks, I would be interested in the refurbished batteries. Money is
                          never plentiful.

                          Actually that is from my heaviest month of power consumption this
                          year. In the winter we only use around 500KWH per month. When I do
                          use a peak, it would be for things like my wood working shop,
                          especially the table saw with heavy duty vacuum. I can easily forgo
                          using this stuff during an emergency. Since I have a complete small
                          appliance outdoor kitchen for summer use, I can avoid using my big
                          stove/oven, nor do I have to have my dryer. We are in the process of
                          adding 2 - 1500 gallon water tanks for rain collection/ water back up
                          so being without the well for a few days is no problem at all. The
                          inverter will power my back up pump that gets water out to the
                          critters. I am set up to be able to switch circuits and so I can
                          arrange to never over power the poor inverter.

                          Last time the power went down I had new calves on the place that
                          weren't use to my electric fence. They were still testing it. Well,
                          the next morning, after the power came back on late at night, I had a
                          pair of calves at the neighbors. And his fence was now hot. I had
                          to wait all day for him to get home to get my calves back. Not a
                          real problem, but if NAIS becomes reality, this could really cost me
                          money. I have to make sure I always have power for my electric fence.

                          While I would not like to live permanently with just a 2500 watt
                          inverter, during a grid down time it is sufficient to prevent any
                          damage from lack of power. We are the tail end of the line and
                          always the last ones to get our power back on. 5 or 6 days with no
                          power can be hard on a deep freeze full of meat, or deadly to a batch
                          of baby birds.

                          Bright Blessings,
                          Kim


                          At 09:33 AM 10/23/2006, you wrote:
                          > > We are working on a back up system for our home for when the grid is
                          > > down. We have a 2500 watt inverter that for now is running off my
                          > > tractor, but I would prefer to have a battery bank for it and just
                          > > charge it from my tractor, as a first step. I have our power
                          > > consumption figured at a maximum of 18 KWH per day. How do I
                          > > translate this to watts or amps or VAs so I can size the battery
                          > > bank? If you choose to give me the answer, please be kind and show
                          > > your calculations so we can learn something.
                          > >
                          >This is going to depend on how long you need power. (Also, even though your
                          >overall consumption is incredibly low, what are your peak needs?)
                          >
                          >Let's assume you want/need 24 hours of off-grid backup.
                          >18KWH is 18000 watts for an hour (equivalent). 18000 watts is 12V (I'm
                          >assuming here, since it's coming off your tractor right now) times 1500A.
                          >So you should need 1500AH of batteries. Say your batteries are rated for
                          >50AH each. You'd then need 30 batteries.
                          >
                          >30 batteries x 50AH = 1500AH
                          >1500AH x 12V = 18000WH (18KWH)
                          >
                          >I think that's right. I'm not an engineer. (I've just been dealing with
                          >UPS's and batteries a lot for work lately.)
                          >
                          >
                          > > What is the opinion of AGM batteries? Are they worth the extra
                          > > money? Garth's company has recently started using them, but not for
                          > > long enough for him to form an opinion of them. The companies
                          > > decision is not necessarily a good recommendation.
                          > >
                          >I think AGM was one of the brands the Toshiba UPS rep recommended when we
                          >talked to him Friday. I've emailed him for a list of recommendations. He had
                          >also mentioned "refurbished" batteries from UPS's. I'll see what it takes to
                          >get hold of some of those.
                          >
                          >Paul
                          >
                          >
                          >
                          >Yahoo! Groups Links
                          >
                          >
                          >
                        • Garth & Kim Travis
                          Greetings, I didn t know there was a NTREG group. I assume that means North Texas Renewable Energy Group? I will go and find the group to join. I have heard
                          Message 12 of 20 , Oct 23, 2006
                            Greetings,
                            I didn't know there was a NTREG group.  I assume that means North Texas Renewable Energy Group? 

                            I will go and find the group to join.  I have heard about telecom batteries from others, but had no idea where to find them.

                            Thanks & Bright Blessings,
                            Kim


                            At 09:52 AM 10/23/2006, you wrote:
                            Kim, if you haven't read the NTREG Yahoo group site lately, you might want to check out recent postings. There will be a number of telcom batteries available soon through a Dallas battery recycling company who has offered them to the RE community before they go public on Ebay.
                             
                            Jim Duncan
                            North Texas Renewable Energy Inc.
                            ntrei@...
                            817.917.0527

                            ----- Original Message -----
                            From: Garth & Kim Travis
                            To: hreg@yahoogroups.com
                            Sent: Monday, October 23, 2006 8:57 AM
                            Subject: [hreg] Technical questions

                            Greetings,

                            We are working on a back up system for our home for when the grid is
                            down. We have a 2500 watt inverter that for now is running off my
                            tractor, but I would prefer to have a battery bank for it and just
                            charge it from my tractor, as a first step. I have our power
                            consumption figured at a maximum of 18 KWH per day. How do I
                            translate this to watts or amps or VAs so I can size the battery
                            bank? If you choose to give me the answer, please be kind and show
                            your calculations so we can learn something.

                            What is the opinion of AGM batteries? Are they worth the extra
                            money? Garth's company has recently started using them, but not for
                            long enough for him to form an opinion of them. The companies
                            decision is not necessarily a good recommendation.

                            Bright Blessings,
                            Kim

                          • Garth & Kim Travis
                            Greetings, I am not sure what information you want, or I would happily supply it. Can you tell me what a load profile is? If I knew, I may be able to tell
                            Message 13 of 20 , Oct 23, 2006
                              Greetings,
                              I am not sure what information you want, or I would happily supply
                              it. Can you tell me what a load profile is? If I knew, I may be
                              able to tell you.
                              Bright Blessings,
                              Kim


                              At 09:59 AM 10/23/2006, you wrote:
                              >Kim,
                              >
                              >Paul raises some of the many variables which would influence your design.
                              >
                              >If we could get a comprehensive view of your load profile, then that will
                              >answer, or prescribe, most of them.
                              >
                              >Regarding batteries, there are likewise some conversion inefficiencies which
                              >need to be addressed in the sizing, in addition to the matter of autonomy
                              >Paul raised.
                              >
                              >On batteries, AGM (Absorbed Glass Mat) is a cell technology, not a brand,
                              >and 30 cells in parallel would be way too many (you only want about 4 max).
                              >
                              >Andrew H. McCalla
                              >NABCEP Certified Solar PV System Installer (TM)
                              >
                              >Meridian Energy Systems
                              >2300 S. Lamar, Ste. 107
                              >Austin, TX 78704
                              >
                              >Voice: (512) 448-0055
                              >Fax: (512) 448-0045
                              >www.meridiansolar.com
                              >
                              >
                            • SBT Designs
                              I still have 8 used T105 Trojans for sale at $25.00 each. Steven Shepard SBT Designs 25581 IH-10 West San Antonio, Texas 78257 (210) 698-7109
                              Message 14 of 20 , Oct 23, 2006
                                I still have 8 used T105 Trojans for sale at $25.00 each.
                                 
                                Steven Shepard
                                SBT Designs
                                25581 IH-10 West
                                San Antonio, Texas 78257
                                (210) 698-7109
                                www.sbtdesigns.com
                                 
                                ----- Original Message -----
                                Sent: Monday, October 23, 2006 10:24 AM
                                Subject: Re: [hreg] Technical questions

                                Greetings,

                                Thanks, I would be interested in the refurbished batteries. Money is
                                never plentiful.

                                Actually that is from my heaviest month of power consumption this
                                year. In the winter we only use around 500KWH per month. When I do
                                use a peak, it would be for things like my wood working shop,
                                especially the table saw with heavy duty vacuum. I can easily forgo
                                using this stuff during an emergency. Since I have a complete small
                                appliance outdoor kitchen for summer use, I can avoid using my big
                                stove/oven, nor do I have to have my dryer. We are in the process of
                                adding 2 - 1500 gallon water tanks for rain collection/ water back up
                                so being without the well for a few days is no problem at all. The
                                inverter will power my back up pump that gets water out to the
                                critters. I am set up to be able to switch circuits and so I can
                                arrange to never over power the poor inverter.

                                Last time the power went down I had new calves on the place that
                                weren't use to my electric fence. They were still testing it. Well,
                                the next morning, after the power came back on late at night, I had a
                                pair of calves at the neighbors. And his fence was now hot. I had
                                to wait all day for him to get home to get my calves back. Not a
                                real problem, but if NAIS becomes reality, this could really cost me
                                money. I have to make sure I always have power for my electric fence.

                                While I would not like to live permanently with just a 2500 watt
                                inverter, during a grid down time it is sufficient to prevent any
                                damage from lack of power. We are the tail end of the line and
                                always the last ones to get our power back on. 5 or 6 days with no
                                power can be hard on a deep freeze full of meat, or deadly to a batch
                                of baby birds.

                                Bright Blessings,
                                Kim

                                At 09:33 AM 10/23/2006, you wrote:
                                > > We are working on a back up system for our home for when the grid is
                                > > down. We have a 2500 watt inverter that for now is running off my
                                > > tractor, but I would prefer to have a battery bank for it and just
                                > > charge it from my tractor, as a first step. I have our power
                                > > consumption figured at a maximum of 18 KWH per day. How do I
                                > > translate this to watts or amps or VAs so I can size the battery
                                > > bank? If you choose to give me the answer, please be kind and show
                                > > your calculations so we can learn something.
                                > >
                                >This is going to depend on how long you need power. (Also, even though your
                                >overall consumption is incredibly low, what are your peak needs?)
                                >
                                >Let's assume you want/need 24 hours of off-grid backup.
                                >18KWH is 18000 watts for an hour (equivalent) . 18000 watts is 12V (I'm
                                >assuming here, since it's coming off your tractor right now) times 1500A.
                                >So you should need 1500AH of batteries. Say your batteries are rated for
                                >50AH each. You'd then need 30 batteries.
                                >
                                >30 batteries x 50AH = 1500AH
                                >1500AH x 12V = 18000WH (18KWH)
                                >
                                >I think that's right. I'm not an engineer. (I've just been dealing with
                                >UPS's and batteries a lot for work lately.)
                                >
                                >
                                > > What is the opinion of AGM batteries? Are they worth the extra
                                > > money? Garth's company has recently started using them, but not for
                                > > long enough for him to form an opinion of them. The companies
                                > > decision is not necessarily a good recommendation.
                                > >
                                >I think AGM was one of the brands the Toshiba UPS rep recommended when we
                                >talked to him Friday. I've emailed him for a list of recommendations. He had
                                >also mentioned "refurbished" batteries from UPS's. I'll see what it takes to
                                >get hold of some of those.
                                >
                                >Paul
                                >
                                >
                                >
                                >Yahoo! Groups Links
                                >
                                >
                                >

                              • Paul Archer
                                ... 30 cells was with a theoretical 50AH per battery. I don t know what s typical for a battery. Assuming that you had, say 200AH cells, you d still need about
                                Message 15 of 20 , Oct 23, 2006
                                  >> On batteries, AGM (Absorbed Glass Mat) is a cell technology, not a brand,
                                  >> and 30 cells in parallel would be way too many (you only want about 4 max).
                                  >>
                                  >> Andrew H. McCalla
                                  >> NABCEP Certified Solar PV System Installer (TM)
                                  >>

                                  30 cells was with a theoretical 50AH per battery. I don't know what's
                                  typical for a battery.

                                  Assuming that you had, say 200AH cells, you'd still need about 8. If you
                                  want a max of 4 in parallel, then a 2x4 series/parallel arrangement would
                                  work (and provide 24V)--but what about the inverter? Do they typically
                                  handle multiple input voltages, or would Kim need a step-down transformer,
                                  or just a new inverter?

                                  Paul
                                • Roy Holder
                                  ... max). ... they go up and up in AH, just cost and weight. ... There are low cost 12, 24, 36 and 48 volt inverters I am aware of. the longer you plan to
                                  Message 16 of 20 , Oct 23, 2006
                                    At 11:15 AM 10/23/2006 -0500, you wrote:
                                    >>> On batteries, AGM (Absorbed Glass Mat) is a cell technology, not a brand,
                                    >>> and 30 cells in parallel would be way too many (you only want about 4
                                    max).
                                    >>>
                                    >>> Andrew H. McCalla
                                    >>> NABCEP Certified Solar PV System Installer (TM)
                                    >>>
                                    >
                                    >30 cells was with a theoretical 50AH per battery. I don't know what's
                                    >typical for a battery.

                                    they go up and up in AH, just cost and weight.

                                    >
                                    >Assuming that you had, say 200AH cells, you'd still need about 8. If you
                                    >want a max of 4 in parallel, then a 2x4 series/parallel arrangement would
                                    >work (and provide 24V)--but what about the inverter? Do they typically
                                    >handle multiple input voltages, or would Kim need a step-down transformer,
                                    >or just a new inverter?
                                    >

                                    There are low cost 12, 24, 36 and 48 volt inverters I am aware of.
                                    the longer you plan to rely on the inverter the higher the voltage of input.
                                    this is because batteries have an limitation that the faster you take out
                                    the amps, the more is lost to internal resistance, reducing the AH the
                                    battery can deliver. Net effect is that a 200 AH battery would only be
                                    able to deliver 120 Amp load in 1 hour before the battery was dead, while
                                    it might be able to deliver 10 amps over 24 hours before it was out of
                                    power for a total of 240 amps.

                                    The higher voltage systems draw less amps for the same load, preserving the
                                    batteries longer than a lower voltage system.




                                    >Paul
                                    >
                                    >
                                    >
                                    >Yahoo! Groups Links
                                    >
                                    >
                                    >
                                    >
                                    >
                                  • Garth & Kim Travis
                                    Greetings, I would like to thank everyone who has responded. Garth got in very late last night and didn t have a chance to read the messages that were posted.
                                    Message 17 of 20 , Oct 24, 2006
                                      Greetings,
                                      I would like to thank everyone who has responded. Garth got in very
                                      late last night and didn't have a chance to read the messages that
                                      were posted. He has an understanding of this stuff, to an
                                      extent. [Electronics not electrical] We will continue this thread
                                      after he gets a chance to read it.
                                      Bright Blessings,
                                      Kim
                                    • Andrew McCalla
                                      Kim, It sounds as if you are getting a lot of great information. I d say with that, your husbands experience, and the article below, you ve got it nailed.
                                      Message 18 of 20 , Oct 24, 2006
                                        Kim,

                                        It sounds as if you are getting a lot of great information.

                                        I'd say with that, your husbands experience, and the article below, you've
                                        got it nailed.

                                        http://www.homepower.com/files/loadcalc.pdf

                                        Feel free to contact me directly if you have any questions.

                                        Andrew H. McCalla
                                        NABCEP Certified Solar PV System Installer (TM)

                                        Meridian Energy Systems
                                        2300 S. Lamar, Ste. 107
                                        Austin, TX 78704

                                        Voice: (512) 448-0055
                                        Fax: (512) 448-0045
                                        www.meridiansolar.com




                                        -----Original Message-----
                                        From: hreg@yahoogroups.com [mailto:hreg@yahoogroups.com] On Behalf Of Garth
                                        & Kim Travis
                                        Sent: Monday, October 23, 2006 10:42 AM
                                        To: hreg@yahoogroups.com
                                        Subject: RE: [hreg] Technical questions

                                        Greetings,
                                        I am not sure what information you want, or I would happily supply
                                        it. Can you tell me what a load profile is? If I knew, I may be
                                        able to tell you.
                                        Bright Blessings,
                                        Kim


                                        At 09:59 AM 10/23/2006, you wrote:
                                        >Kim,
                                        >
                                        >Paul raises some of the many variables which would influence your design.
                                        >
                                        >If we could get a comprehensive view of your load profile, then that will
                                        >answer, or prescribe, most of them.
                                        >
                                        >Regarding batteries, there are likewise some conversion inefficiencies
                                        which
                                        >need to be addressed in the sizing, in addition to the matter of autonomy
                                        >Paul raised.
                                        >
                                        >On batteries, AGM (Absorbed Glass Mat) is a cell technology, not a brand,
                                        >and 30 cells in parallel would be way too many (you only want about 4 max).
                                        >
                                        >Andrew H. McCalla
                                        >NABCEP Certified Solar PV System Installer (TM)
                                        >
                                        >Meridian Energy Systems
                                        >2300 S. Lamar, Ste. 107
                                        >Austin, TX 78704
                                        >
                                        >Voice: (512) 448-0055
                                        >Fax: (512) 448-0045
                                        >www.meridiansolar.com
                                        >
                                        >




                                        Yahoo! Groups Links
                                      • noyes livingston
                                        John, I spoke to you earlier and never moved on it. I have enough money to at least put in a solar powered attic fan and perhaps for a small emergency solar
                                        Message 19 of 20 , Nov 11, 2006
                                          John,
                                           
                                          I spoke to you earlier and never moved on it.  I have enough money to at least put in a solar powered attic fan and perhaps for a small emergency solar powered backup due to power loss.
                                           
                                          I would also like to know if you could direct me in obtaining a loan ( I understand there are govt backed loans for "green" projects) to set up a decent RE system.  The idea is to create a patio that has enough solar panels mounted to provide power to at least some loads in our home.
                                           
                                          I would like to eventually move out of Houston and move on to bigger projects and learn.  Incidentally, my father has a home in Port Aransas and I am trying to sell him on the idea of a small turbine.  Do you have any idea on the cost to power a home of less than 1000 ft sq with modest electricity demands?
                                           
                                          Noyes Livingston

                                          ----- Original Message ----
                                          From: John Miggins <jmiggins@...>
                                          To: hreg@yahoogroups.com
                                          Sent: Monday, October 23, 2006 9:23:02 AM
                                          Subject: Re: [hreg] Technical questions

                                          Kim, here is a handy guide to help size the battery bank and solar system.
                                          there needs to be some judgement applied to this as to how many days of back-up you want etc...
                                           
                                          AGM batteries are less hassle since they require little maintenance, they will last from 3 to 5 years.  Most large solar system used lead acid, unsealed batteries that allow you to check the state of charge and add water when needed.  They last longer so cost less in the long run.
                                           
                                          Rolls Surrette, Trojan or others are a good investment.  If the batteries are just for occasional use for back-up I would then use sealed ones .
                                           
                                          Google Solar batteries and you will find more info than you need.
                                           
                                           
                                           
                                           
                                          John Miggins
                                          Harvest Solar & Wind Power
                                          "renewable solutions to everyday needs"
                                          www.harvest-energy.com
                                          Phone/Fax 918-743-2299
                                          Cell: 918-521-6223
                                          ----- Original Message -----
                                          Sent: Monday, October 23, 2006 8:57 AM
                                          Subject: [hreg] Technical questions

                                          Greetings,

                                          We are working on a back up system for our home for when the grid is
                                          down. We have a 2500 watt inverter that for now is running off my
                                          tractor, but I would prefer to have a battery bank for it and just
                                          charge it from my tractor, as a first step. I have our power
                                          consumption figured at a maximum of 18 KWH per day. How do I
                                          translate this to watts or amps or VAs so I can size the battery
                                          bank? If you choose to give me the answer, please be kind and show
                                          your calculations so we can learn something.

                                          What is the opinion of AGM batteries? Are they worth the extra
                                          money? Garth's company has recently started using them, but not for
                                          long enough for him to form an opinion of them. The companies
                                          decision is not necessarily a good recommendation.

                                          Bright Blessings,
                                          Kim



                                        • Bashir Syed
                                          Size of a home has nothing to do with the system one needs to install. It depends on the average total energy per day needed to operate lights, fans, other
                                          Message 20 of 20 , Nov 11, 2006
                                            Size of a home has nothing to do with the system one needs to install. It depends on the average total energy per day needed to operate lights, fans, other small appliances (like radio, TV etc.) for a Stand-Alone System, which would require a battery bank to store energy during the time SUN-shine is not available. 
                                            For a grid-tied, one does not need battery-bank to store energy as PV-array continuously feed s the energy to the grid through an Inverter plus a few essential parts.
                                             
                                            Bashir A. Syed
                                             
                                            ----- Original Message -----
                                            Sent: Saturday, November 11, 2006 5:54 AM
                                            Subject: Re: [hreg] Technical questions

                                            John,
                                             
                                            I spoke to you earlier and never moved on it.  I have enough money to at least put in a solar powered attic fan and perhaps for a small emergency solar powered backup due to power loss.
                                             
                                            I would also like to know if you could direct me in obtaining a loan ( I understand there are govt backed loans for "green" projects) to set up a decent RE system.  The idea is to create a patio that has enough solar panels mounted to provide power to at least some loads in our home.
                                             
                                            I would like to eventually move out of Houston and move on to bigger projects and learn.  Incidentally, my father has a home in Port Aransas and I am trying to sell him on the idea of a small turbine.  Do you have any idea on the cost to power a home of less than 1000 ft sq with modest electricity demands?
                                             
                                            Noyes Livingston

                                            ----- Original Message ----
                                            From: John Miggins <jmiggins@cox. net>
                                            To: hreg@yahoogroups. com
                                            Sent: Monday, October 23, 2006 9:23:02 AM
                                            Subject: Re: [hreg] Technical questions

                                            Kim, here is a handy guide to help size the battery bank and solar system.
                                            there needs to be some judgement applied to this as to how many days of back-up you want etc...
                                             
                                            AGM batteries are less hassle since they require little maintenance, they will last from 3 to 5 years.  Most large solar system used lead acid, unsealed batteries that allow you to check the state of charge and add water when needed.  They last longer so cost less in the long run.
                                             
                                            Rolls Surrette, Trojan or others are a good investment.  If the batteries are just for occasional use for back-up I would then use sealed ones .
                                             
                                            Google Solar batteries and you will find more info than you need.
                                             
                                             
                                             
                                             
                                            John Miggins
                                            Harvest Solar & Wind Power
                                            "renewable solutions to everyday needs"
                                            www.harvest- energy.com
                                            Phone/Fax 918-743-2299
                                            Cell: 918-521-6223
                                            ----- Original Message -----
                                            Sent: Monday, October 23, 2006 8:57 AM
                                            Subject: [hreg] Technical questions

                                            Greetings,

                                            We are working on a back up system for our home for when the grid is
                                            down. We have a 2500 watt inverter that for now is running off my
                                            tractor, but I would prefer to have a battery bank for it and just
                                            charge it from my tractor, as a first step. I have our power
                                            consumption figured at a maximum of 18 KWH per day. How do I
                                            translate this to watts or amps or VAs so I can size the battery
                                            bank? If you choose to give me the answer, please be kind and show
                                            your calculations so we can learn something.

                                            What is the opinion of AGM batteries? Are they worth the extra
                                            money? Garth's company has recently started using them, but not for
                                            long enough for him to form an opinion of them. The companies
                                            decision is not necessarily a good recommendation.

                                            Bright Blessings,
                                            Kim



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