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  • #16
    PV systems

    Are you worried about return on investment? If you can't get the system for a buck a watt you'll never get a reasonable payback. Evan is correct about the load etc. A much cheaper alternative would be to install CFLs and Super T8 light fixtures and high efficiency motors on your equipment. You have to decide on what you want save money or self-sufficency. Remember a battery rack isn't maintenance free and should ideally be contained in a seperate dedicated building.
    I recently did a cost analysis for a 5kw system, my numbers were in the 70-80 range, the contractor can back with a 100k quote.
    Non, je ne regrette rien.

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    • #17
      Originally posted by AZSORT
      The only time to even consider using a battery tied solar system is if you are in an off-grid situation. The batteries are still the biggest problem - being expensive maintanence headache, safety and reliability issue, and significantly hurt the system efficiency. The way to go anymore (as long as you are on the grid) is a grid-tie inverter that can track the max power point of your panels and extract every precious watt out of them.
      Most ANY decent charge controller these days will do max power point tracking, that is NOT reserved for grid tie.

      Batteries are hardly an expensive maintenance item, and they DO provide backup power thru the inverter, which you cannot get from a grid-tie-only. Most grid tie units shut down if the grid goes out, that is an IEEE requirement to prevent "islanding". That type will not provide local power unless you can manually over-ride, and naturally would require batteries to provide power off-solar-peak or at night. I'd never consider such a system for a moment.

      I have had the same T105 batteries in the system for over 12 years, and they still have sufficient capacity to be quite usable, somewhere around 80 to 90 percent of original capacity, maybe more. I just feed them some distilled water as needed.

      Properly located and fused, they are not a safety hazard either.

      The most expensive maintenance item in my system has been the panels. They had to be replaced after the tree fell on them (from the North), and naturally were not insured.
      Last edited by J Tiers; 09-08-2007, 11:42 PM.
      1601

      Keep eye on ball.
      Hashim Khan

      Comment


      • #18
        I've looked into light tubes before,they look good for daytime light,but most of my shop time will be at night.

        If I go with a two panel system all it will cost extra is the cost of a 6 circut panel and an extra ground rod since I do my own wiring.Even if I don't go with solar now it will be ready to plug and play if something happens later like super cheap panels.

        Even though I will be on the grid,things like hurricanes happen and it would be nice to have a backup for my refrigerator and maybe a fan or two.Plenty of sunlight after a hurricane,but little fuel for generators.

        What intriques me is a setup a friend has at his fishing camp.It's off grid and generators make noise so he bought 2-45 watt Chinese solar panels,a 3500 watt inverter and a 1,000amp tractor battery.With that setup he can run all the lights he wants,and a small portable cooler all weekend.He has been doing this once or twice a month for three years and has yet to need a new battery.
        Now I realise that isn't going to happen that easy for me since he has a long recovery time availible between fishing trips,but it still looks promising with a bit more infrastructure.

        Besides HF has the panels on sale right now
        I just need one more tool,just one!

        Comment


        • #19
          How good are the HF panels?

          TMT

          Comment


          • #20
            Originally posted by Too_Many_Tools
            How good are the HF panels?

            TMT
            Dunno,they are similar to the ones Buddy bought,same type cells as I recall.His are just sitting on the south slope of the camp roof with a 3/16" plexiglass shield over top.Absolutly nothing fancy.

            There on sale $199 including the controller not counting a 15% one item coupon they have running.
            I just need one more tool,just one!

            Comment


            • #21
              Got Rhode Island Red cartoon character in my head.......

              "I say I say come on men, answer the booooys question! I say I say the sale ain't gonna last forever you know!"

              My trailer has a round vaulted roof and these particular units (3seperate one to a panel) would lay nice on the roof.
              - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
              Thank you to our families of soldiers, many of whom have given so much more then the rest of us for the Freedom we enjoy.

              It is true, there is nothing free about freedom, don't be so quick to give it away.

              Comment


              • #22
                Ok. Simple answer is that solar electric still can't compete with grid prices. For the times the grid is down you are better off to have a diesel backup. Diesel fuel keeps well so availability shouldn't be a problem if you plan ahead.
                Free software for calculating bolt circles and similar: Click Here

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                • #23
                  When the grid is down, and you run out of fuel, the cost per kilowatt hour is just not very important........
                  1601

                  Keep eye on ball.
                  Hashim Khan

                  Comment


                  • #24
                    That's where the planning part comes in.
                    Free software for calculating bolt circles and similar: Click Here

                    Comment


                    • #25
                      Originally posted by Evan
                      That's where the planning part comes in.
                      Plan for a week, power will be out 9 days..... Plan for two weeks, power will be out 3.

                      Plan for 6 months...... Naw, forget it.............

                      How long has power been out in parts of New Orleans now? How long was it out in Mississippi?

                      Power was out in St Louis for 10 days a year ago July, and out for 6 last December. It would be very reasonable here to plan for 3 or 4 days....... (at least it WAS reasonable)

                      Also, there are a lot more things to go wrong with a diesel plant, or gasoline plant, than there are with cells and batteries, 12V lamps, Peltier coolers, etc. Those things are the fallback if the inverters croak.

                      The fallback with a diesel genset only is the Red Cross shelter..... or doing without.
                      Last edited by J Tiers; 09-09-2007, 11:36 AM.
                      1601

                      Keep eye on ball.
                      Hashim Khan

                      Comment


                      • #26
                        Here's a link to an article I wrote several years ago on the subject of solar power for RVs: http://www.fiberglassrv.com/solar.html

                        Since the article was written, we've changed trailers and now use an MPPT controller and 2 golf cart batteries. Most of the rest still applies.

                        As others have said, if your object is to save money by using solar power, you should lay down until the temptation passes: it ain't gonna happen. If you want backup, get a generator, fueled either by Diesel or propane; Diesel fuel keeps pretty well, and propane will keep forever. You should be able to store enough fuel for at least several days, and by then you should be able to get to some place to get more. Be sure to exercise your generator regularly, or it won't work when you need it. My genset is shown here:
                        http://www.oldengine.org/members/jdunmyer/genset/

                        Rigid conservation measures will save much more $$$ than any solar system.

                        My comments do not apply if you're off-grid.

                        Comment


                        • #27
                          Originally posted by Your Old Dog
                          Got Rhode Island Red cartoon character in my head.......

                          "I say I say come on men, answer the booooys question! I say I say the sale ain't gonna last forever you know!"

                          My trailer has a round vaulted roof and these particular units (3seperate one to a panel) would lay nice on the roof.
                          He was a HSM you know,Foghorn Leghorn,ever see the one where he is chasing the dog around the barnyard when he stops and chops down a tree drags it into the shop and spins a ball bat out of it to whack the dog?
                          I just need one more tool,just one!

                          Comment


                          • #28
                            I'm not looking for free electricity,pay me now pay me later is still in effect.If I could shave a few dollars off my monthly bill it would be nice.Using the system after a storm for running a few lights or fans or for that matter just saving a freezer of food would be nicer.In that case the cost of a small home built system might payback in a couple weeks.

                            I rode out Katrina,power was off two weeks here,1-1/2 in town and then on again off again for about 4 months later.A 5,000 watt Briggs generator drank 7 gallons of gas in about 8-9hrs run time,gas when you could find it was $5+.All that generator did was run lights a couple hours after dark and a couple fans so we could sleep,it sat idle during the day.$35/day especially when gas is scarce and you have basicaly no income because work has shutdown is difficult to manage.In two weeks of run time $500 goes down the toilet not counting the cost of the generator in the first place.From what I see a small home system could be assembled for less than $2,000.Diffrence is the solar system is quiet and won't be running out of fuel anytime soon.

                            I know the flaw in my thinking is possible damage to the panels in a storm,simple answer is bring them inside until the storm is past,average storms can be handled by plexi covers.After a storm like Katrina payback could be in a matter of a couple weeks.

                            We haven't even considered the age of our grid system and the possibility of terrorism.IMHO our grid system is one of the weakest areas we have and I believe the crazies realise this too unfortunately.
                            I just need one more tool,just one!

                            Comment


                            • #29
                              The panels the tree smashed were "folded over", the top 1/3 of the panel was at a 60 deg angle to the rest.

                              But, they were actually still putting out about 40% of the power they had before being squashed.

                              Arrays are not necessarily that fragile. And new ones have very substantial frames. The frames of the individual Carrizo panels were minimal, almost an "edging" only.

                              The overall frame was bent by the tree, or the panels might have been un-damaged. The tree fell about 40 feet and the panel setup was hit by two forks in the branch. The first one the panels actually split off the tree, likely without damage, but the second and larger one bent them.

                              I assembled my system for less than $1000, including a 2500W inverter, but you can't do that now. Panels have gone up a lot, and no more used ones are out there. Apparently some countries have tax credits, and they are buying every panel that can be made... no discounts.
                              Last edited by J Tiers; 09-10-2007, 10:38 PM.
                              1601

                              Keep eye on ball.
                              Hashim Khan

                              Comment


                              • #30
                                Originally posted by J Tiers
                                The panels the tree smashed were "folded over", the top 1/3 of the panel was at a 60 deg angle to the rest.

                                But, they were actually still putting out about 40% of the power they had before being squashed.

                                Arrays are not necessarily that fragile. And new ones have very substantial frames. The frames of the individual Carrizo panels were minimal, almost an "edging" only.

                                The overall frame was bent by the tree, or the panels might have been un-damaged. The tree fell about 40 feet and the panel setup was hit by two forks in the branch. The first one the panels actually split off the tree, likely without damage, but the second and larger one bent them.

                                I assembled my system for less than $1000, including a 2500W inverter, but you can't do that now. Panels have gone up a lot, and no more used ones are out there. Apparently some countries have tax credits, and they are buying every panel that can be made... no discounts.
                                I'm not as concerned with tree damage as I am them turning in to frisbies and ending up with Dorthy and Toto,but it is incouraging that they can take some abuse and still function.

                                There are some panels out there that aren't too bad price wise,the Chinese models for one.

                                How much wattage in panels did you have for what capacity system?
                                I just need one more tool,just one!

                                Comment

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