Announcement

Collapse
No announcement yet.

PV Combiner Box for 24 Panels

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

  • #31
    Originally posted by littleharbor View Post

    Thanks Mike, As suggested previously, I thought the 3 strings is "ok" was bad and potentially dangerous advice.
    Depends on the Isc and the fuse rating. If the Isc is 6A and the fuse rating is 15A... how would you exceed 15A with 3 strings? If the Isc is 9A and the fuse rating is 15A you absolutely need fuses for 3 strings.

    Screen Shot 2019-07-05 at 6.31.09 PM.png
    Last edited by nwdiver; 07-05-2019, 08:32 PM.

    Comment


    • #32
      Originally posted by nwdiver View Post

      Depends on the Isc and the fuse rating. If the Isc is 6A and the fuse rating is 15A... how would you exceed 15A with 3 strings? If the Isc is 9A and the fuse rating is 15A you absolutely need fuses for 3 strings.
      Because most panels don't specify over 200% for the series fuse. a 6A panel often has a 10a or 12a fuse spec'd. I go with the common experience, not the odd exception.
      Congratulations for quoting something, from sometime.

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

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

      Comment


      • #33
        Originally posted by Mike90250 View Post

        Because most panels don't specify over 200% for the series fuse. a 6A panel often has a 10a or 12a fuse spec'd. I go with the common experience, not the odd exception.
        Congratulations for quoting something, from sometime.
        The quote is from the NEC 690.9 (A) exemption b; I think it's useful to understand the basis of a rule. If the combined short circuit ampacity is < the fuse rating fusing is not required. Usually this is 2 or fewer strings. Sometimes it's 3 or fewer. Depends.

        Comment


        • #34
          Generally, with neophytes and electrical gear, advice is given in the cautious mode. When I'm at burning man, I play safety 3rd, but not here with folks that barely know a watt from a volt.

          Do you want to be part of the problem, and have people hate solar 'cause it burned their house down, or have them think it's expensive at first, and then slowly pays back ?
          Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
          || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
          || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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

          Comment


          • #35
            Originally posted by Mike90250 View Post
            Generally, with neophytes and electrical gear, advice is given in the cautious mode. When I'm at burning man, I play safety 3rd, but not here with folks that barely know a watt from a volt.
            W = V x A... is that right? 😀This neophyte with only MFA in vide/film/performance art from UCLA has worked in audio visual field for 35+ years; is trying to learn about solar off grid systems which, of course, is a very specialized field with its own terminology etc.

            Right now, all I use for my electric power needs is Goal Zero Yeti 3000 solar generator with 8 x 100 Renogy/HQSL panels. I already like it millions times better than few of my Champion and Briggs&Stratton inverter gas generators.
            It can almost run my 20" whole house window fan, mini fridge and my LED lights all day long but my microwave shuts it off in less than 30 sec.

            So I would like to upgrade my solar power if it's possible that I can do it all by myself; not because of the cost of hiring someone but for several other reasons.
            Maybe l can learn how to do it by reading and asking questions here. Only time will tell.

            I think l almost know now how to deal with the solar panels and maybe I am sold on Midnite Classic 200. My last question about the batteries needs is still open then I'll move to inverter charger questions.
            Last edited by Bozant; 07-06-2019, 09:16 AM.

            Comment


            • #36
              Originally posted by Bozant View Post
              Then, if I understand you correctly, I can use the Midnite Classic 200 with lithium or other batteries because I'd be able to set its voltage to the voltage required by the batteries?
              I guess the next thing is deciding the type, brand, size and the voltage for the battery bank. Any suggestions? Please! Thank you!
              Yes, the midnight classic is very adjustable, either by the front panel controls, or by the Local App over ethernet.
              the sale of a small batch of a custom surplus run, is about the best price you will ever see, if the stripped down version meets your needs
              http://midniteftp.com/forum/index.php?topic=4606.0

              I guess the next thing is deciding the type, brand, size and the voltage for the battery bank. Any suggestions? Please! Thank you!
              Several things set the battery:
              24 hour load (in watt hours)
              Peak Load (in watts, your microwave, coffee pot, well pump)

              For example, my average daily load is about 350watts, but to start my well pump, I need a 6kw inverter. Going large on an inverter means it consumes as much power at idle as some small appliances. So if you don't have a fridge or microwave or well pump, you can get by with a pretty minimal system.

              So, the more accurate your load calculations, the more "rightly sized" your system can be. I like to think a good starter system is four golf cart batteries, in series, gives a 24V 200ah system.
              batteries are cheap, won't last more than 4 years, and you learn a lot about the gear without spending big bucks. When battery replacement time comes, you will know if you are ready for a lithium battery bank and all the requirements for it (runs between 40F - 95F, needs BMS, not inside your building envelope)



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

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

              Comment


              • #37
                Originally posted by Mike90250 View Post
                So, the more accurate your load calculations, the more "rightly sized" your system can be. I like to think a good starter system is four golf cart batteries, in series, gives a 24V 200ah system.
                batteries are cheap, won't last more than 4 years, and you learn a lot about the gear without spending big bucks. When battery replacement time comes, you will know if you are ready for a lithium battery bank and all the requirements for it (runs between 40F - 95F, needs BMS, not inside your building envelope)
                No way. I need minimum 8500WH per day. I like to have at least 2 of my Air King 20" whole house window fans running 24/7. With my LED lights and mini fridge, I am using on average at least 350Wh. In winter I may even want to use some of my 1500W electric heaters.

                My main reason for upgrading from Yeti 3000 lithium solar generator, 1500W, 270AH, 3000WA is because it can't run my microwave. My peak AC power has to be at least 3000W with the surge higher than that. I also use electric tools.

                You have to understand that I've been using Inverter gas generators for my electric needs for some time now. I have 3 of them each 3500W continuous power and a small one 2300W that won't start. I can use these to charge my solar batteries when there is not much 🌞. I am in 3 -- 3.5 sun peak hrs, Brooklyn NY.

                I learn these things by using solar generator for couple of months now. It tells me how many Watts are going out and how many coming in, what % is my battery at, how many hours of running time, how many for full charge, how many till empty.

                I want lithium batteries because of safety, weight and easy operation, don't want to have to worry about over discharge fumes and fire. There are 3 brands I am thinking about: BattleBorn, Aims Power and LifeBlue. BTW, I'm not poor. Wondering if anyone has any opinion about these?


                Comment


                • #38
                  Originally posted by Bozant View Post
                  No way. I need minimum 8500WH per day. I like to have at least 2 of my Air King 20" whole house window fans running 24/7. With my LED lights and mini fridge, I am using on average at least 350Wh. In winter I may even want to use some of my 1500W electric heaters
                  .........
                  .........
                  I want lithium batteries because of safety, weight and easy operation, don't want to have to worry about over discharge fumes and fire. There are 3 brands I am thinking about: BattleBorn, Aims Power and LifeBlue. BTW, I'm not poor. Wondering if anyone has any opinion about these?

                  > worry about over discharge fumes and fire
                  Yep, that's the failure scenario for Li batteries, and why they should not be in the building you live in. Even this year, laptops are still burning up, and those are the highest screened batteries except for what launches into space.

                  With the sort of loads you mention, you are solidly in 48V bank territory. For bad weather, will you retain a generator for power, when the sun isn't ?

                  8.5kwh daily, needs double that in battery capacity, which gives you 1 cloudy day before flat. 17kwh of battery @ 48V is going to be a 350 - 400ah battery, and it's not going to run your electric heater very long.
                  Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                  || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                  || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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

                  Comment


                  • #39
                    Originally posted by Bozant
                    In winter I may even want to use some of my 1500W electric heaters.

                    I also use electric tools.
                    Resistance electric heaters are about the quickest way there is to destroy your energy
                    reserve. Get high efficiency mini split heat pumps and multiply your efficiency maybe
                    4 times. Obviously can be used for AC as well.

                    Unless you have a saw mill, intermittent hand tools will not accumulate enough running
                    time to be a big problem. Which is why battery powered versions are practical.
                    Bruce Roe

                    Comment


                    • #40
                      Originally posted by Mike90250 View Post

                      > worry about over discharge fumes and fire
                      Yep, that's the failure scenario for Li batteries, and why they should not be in the building you live in. Even this year, laptops are still burning up, and those are the highest screened batteries except for what launches into space.
                      What? Is this based on sound science, research and testing or a personal opinion? All the sources I've checked are telling me that LiFePO4 is the way to go for a slow discharge battery and I'm not talking about only couple of sources or a YouTube video. Although, how long they will last is not my main concern, I'll probably be dead in 4 years, I would like batteries free of maintenance, clean, easy to handle that I can put in my house right next to the rest of the stuff on a good wire cart with wheels.

                      Originally posted by Mike90250 View Post
                      With the sort of loads you mention, you are solidly in 48V bank territory. For bad weather, will you retain a generator for power, when the sun isn't ?

                      8.5kwh daily, needs double that in battery capacity, which gives you 1 cloudy day before flat. 17kwh of battery @ 48V is going to be a 350 - 400ah battery, and it's not going to run your electric heater very long.
                      Yes, I will have to use my gas generators to charge when sun input is very low for days (that happens here a lot); as much as I hate walking to the gas station with a shopping cart to get 20 gl of gas each trip. I was thinking about starting with 4 or 6 x 12V, 100Ah = 400Ah-- 600Ah at 12V and adding if I need to. I guess l would have to hook them up in series somehow to get 48V. With these: SimpliPhi PHI 3.5 kWh 48v 69 Ah LFP Battery, I would need only two but they maybe too heavy for me, more than 70lb.

                      Comment


                      • #41
                        Originally posted by Bozant View Post
                        What? Is this based on sound science, research and testing or a personal opinion?
                        You will have to read for yourself, about what happens to a lithium battery that is overly discharged or over charged. Either way, ends badly.
                        https://batteryuniversity.com/learn/..._ion_batteries
                        Flooded lead acid batteries are amazingly forgiving, just add a bit more water, or recharge before 48hr elapses to avoid sulfation. They have some stinky fumes and hydrogen to vent, and that is easily handled with an outdoor vented battery box.
                        When Li batteries go bad, they short internally, heat up, vent toxic hydrofluoric acid vapors (takes a painful week to kill you)
                        Here's a jolly article about that https://www.nature.com/articles/s41598-017-09784-z & https://batteryuniversity.com/learn/...ns_with_li_ion
                        This thermal runaway that occurs is known as "venting with flame." "Rapid disassembly" is the preferred term by the battery industry.


                        Yes, I will have to use my gas generators to charge when sun input is very low for days (that happens here a lot); as much as I hate walking to the gas station with a shopping cart to get 20 gl of gas each trip. I was thinking about starting with 4 or 6 x 12V, 100Ah = 400Ah-- 600Ah at 12V and adding if I need to. I guess l would have to hook them up in series somehow to get 48V. With these: SimpliPhi PHI 3.5 kWh 48v 69 Ah LFP Battery, I would need only two but they maybe too heavy for me, more than 70lb.
                        Your stated loads require about 17 - 20 kwh of battery, which is 350 - 400ah @ 48V. it does not matter if lead acid or LFP, that's the minimum battery to reliably make it through nights in winter, unless you don't mind the inverter shutting down from low battery.
                        trying to start with a small bank, and build up to a larger bank is not a good choice. If you use lead acid, you will be adding fresh batteries to worn/aged batteries, which quickly makes the new batteries equal in age to the oldest/worst battery (this happens in weeks)
                        Li chemistry, you have to have a BMS that can expand as you add more cells. And we've not even started with Top Balance vs Bottom Balance.

                        Endlessly adding more batteries is a fools errand, and I caution you against spending your $ down that sewer hole. 48V, 400ah is the smallest to start with, and even that is marginal. That's going to be 16 golf cart batteries wired 8S2P for 48V 400ah. At $100 each you are in for $1,600 plus connecting cables. You can price the lithium and see what you get, you won't like it.

                        Your desired loads are too much for a 12V system, marginal at 24V, and usable at 48V. one of your 1500w heaters will consume about 140A at 12V. The cabling required to carry only that is prohibitive, and well manufactured 2Kw 12V inverters are rare and expensive. Sure, there's lots of 12v inverters with a 4kw sticker, but they are not safe.

                        Li batteries also have strict charging constraints when cold. Below 40F, their efficency drops off, and at 33F (or 32 if you dare) they cannot be recharged at all. If charged when cold, they will be damaged and prone to Rapid disassembly when recharged. https://batteryuniversity.com/index....w_temperatures

                        Marinate in this information, this is not BS from the YouFool cheering section of the intertubes, this is real life stuff for a safe install

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

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

                        Comment


                        • #42
                          Now this neophyte feels as if hit in the head with a 200 lbs flooded battery.

                          Mike90250, my understanding is that lithium-ion, the subject in your links and lithium-iron, LiFePO4 are different. But even with lithium-ion, to quote from your link:

                          "With more than a billion mobile phones and computers used in the world every day, the number of accidents is small. By comparison, the National Oceanic and Atmospheric Administration say that your chance of being struck by lightning in the course of a lifetime is about 1 in 13,000. Lithium-ion batteries have a failure rate that is less than one in a million. The failure rate of a quality Li-ion cell is better than 1 in 10 million."

                          "While lithium-based batteries are heavily studied for safety, nickel- and lead-based batteries also cause fires and are being recalled. The reasons are faulty separators resulting from aging, rough handling, excessive vibration and high-temperature. Lithium-ion batteries have become very safe and heat-related failures occur rarely when used correctly."

                          Moreover, are you saying that this, for example is false?

                          "LiFePO4 batteries are the safest type of Lithium batteries as they will not overheat, and even if punctured they will not catch on fire. The cathode material in LiFePO4 batteries is not hazardous, and so poses no negative health hazards or environmental hazards. Due to the oxygen being bonded tightly to the molecule, there is no danger of the battery erupting into flames like there is with Lithium-Ion. The chemistry is so stable that LiFePO4 batteries will accept a charge from a lead-acid configured charge."

                          Is this also false?

                          "Like nickel-based rechargeable batteries (and unlike other lithium ion batteries), LiFeP4 batteries have a very constant discharge voltage. Voltage stays close to 3.2 V during discharge until the cell is exhausted. This allows the cell to deliver virtually full power until it is discharged, and it can greatly simplify or even eliminate the need for voltage regulation circuitry."

                          How about this, is it nonsense?

                          "Most lead acid batteries experience significantly reduced cycle life if they are discharged more than 50%, which can result in less than 300 total cycles. Conversely LIFEPO4 (lithium iron phosphate) batteries can be continually discharged to 100% DOD and do there is no long term effect. You can expect to get 3000 cycles or more at this depth of discharge."

                          If I'm to believe the last quote; wouldn't discharging my batteries to 100% give me twice as much watts per hour than if I was discharging them only 50%, therefore cutting down on my battery bank size need 50%?

                          As for low temperature, isn't that irrelevant since I plan to keep the batteries in my house with temperatures never reaching 32 F or I would have big problem with my water pipes and myself freezing?

                          And also, with LiFePO4, my understanding is that there is no problem with adding more of them to the battery bank at any time which I think is great. It allows you to start with fewer batteries and add on as you feel how it all works for you through all the seasons.

                          One more thing. The weight for an old person, disabled with PD is a big factor.

                          So, go head, lighten me' where am I wrong?

                          BTW, I am aware of the high price of LifePO4. No big problem. Don't have much time left. Don't have anyone to leave my $ except for the birds but they wouldn't know how to use it to buy seeds.

                          Comment


                          • #43
                            LFP (LiFePO4) are the "safest" Li battery style. But they are not immune.
                            https://batteryuniversity.com/learn/...ns_with_li_ion
                            If you like MORE safe batteries consider LiFePO4 these are more safe than Lithium-ion and also have a much longer lifespan. 2000 cycles instead of 300-500 for Lithium-Ion's

                            Now regarding these comments:

                            Is this also false?
                            "Like nickel-based rechargeable batteries (and unlike other lithium ion batteries), LiFeP4 batteries have a very constant discharge voltage. Voltage stays close to 3.2 V during discharge until the cell is exhausted. This allows the cell to deliver virtually full power until it is discharged, and it can greatly simplify or even eliminate the need for voltage regulation circuitry."

                            How about this, is it nonsense?
                            "Most lead acid batteries experience significantly reduced cycle life if they are discharged more than 50%, which can result in less than 300 total cycles. Conversely LIFEPO4 (lithium iron phosphate) batteries can be continually discharged to 100% DOD and do there is no long term effect. You can expect to get 3000 cycles or more at this depth of discharge."
                            I've no idea where these came from. Those quotes are wildly optimistic. Even LFP is only recommended to cycle from 90% full to 20% full , using 70% of the battery.
                            ONLY if you have experience with electronics, and completely understand the Li voltage cycle, you "might" be able, with redundant safeties , be able to take a Top or Bottom balanced pack (this is a exacting procedure) and be able to run it without a BMS. I figure 1% of users have the discipline to do this correctly over a period of years.


                            http://robotsforroboticists.com/lith...attery-safety/
                            2b. Lithium-ion batteries (including LiFePO4, etc...) that are used on many robots, are often larger and rechargeable. For these batteries there is not a lot of actual lithium metal in the battery, so you can use water, class ABC fire extinguisher, or CO2 extinguisher. The CO2 extinguisher are often nice since they do not leave a bad residue on your electronics. You do not use a class D extinguisher with these batteries. You will most likely need a lot of water or extinguishers.
                            &
                            3. Only charge batteries in designated areas. A designated area should be non combustible. For example cement, sand, cinder block and metal boxes are not uncommon to use for charging areas. For smaller cells you can purchase fire containment bags designed to put the charging battery in.


                            You are welcome to do your own research and come to your own conclusions. I'm being conservative. Put them in a safe place. Limit capacity usage. monitor closely.
                            They are lightweight, they are not cheap.
                            Powerfab top of pole PV mount (2) | Listeroid 6/1 w/st5 gen head | XW6048 inverter/chgr | Iota 48V/15A charger | Morningstar 60A MPPT | 48V, 800A NiFe Battery (in series)| 15, Evergreen 205w "12V" PV array on pole | Midnight ePanel | Grundfos 10 SO5-9 with 3 wire Franklin Electric motor (1/2hp 240V 1ph ) on a timer for 3 hr noontime run - Runs off PV ||
                            || Midnight Classic 200 | 10, Evergreen 200w in a 160VOC array ||
                            || VEC1093 12V Charger | Maha C401 aa/aaa Charger | SureSine | Sunsaver MPPT 15A

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

                            Comment


                            • #44
                              Originally posted by Mike90250 View Post
                              LFP (LiFePO4) are the "safest" Li battery style. But they are not immune.
                              https://batteryuniversity.com/learn/...ns_with_li_ion
                              If you like MORE safe batteries consider LiFePO4 these are more safe than Lithium-ion and also have a much longer lifespan. 2000 cycles instead of 300-500 for Lithium-Ion's

                              Now regarding these comments:



                              I've no idea where these came from. Those quotes are wildly optimistic. Even LFP is only recommended to cycle from 90% full to 20% full , using 70% of the battery.
                              ONLY if you have experience with electronics, and completely understand the Li voltage cycle, you "might" be able, with redundant safeties , be able to take a Top or Bottom balanced pack (this is a exacting procedure) and be able to run it without a BMS. I figure 1% of users have the discipline to do this correctly over a period of years.


                              http://robotsforroboticists.com/lith...attery-safety/
                              2b. Lithium-ion batteries (including LiFePO4, etc...) that are used on many robots, are often larger and rechargeable. For these batteries there is not a lot of actual lithium metal in the battery, so you can use water, class ABC fire extinguisher, or CO2 extinguisher. The CO2 extinguisher are often nice since they do not leave a bad residue on your electronics. You do not use a class D extinguisher with these batteries. You will most likely need a lot of water or extinguishers.
                              &
                              3. Only charge batteries in designated areas. A designated area should be non combustible. For example cement, sand, cinder block and metal boxes are not uncommon to use for charging areas. For smaller cells you can purchase fire containment bags designed to put the charging battery in.


                              You are welcome to do your own research and come to your own conclusions. I'm being conservative. Put them in a safe place. Limit capacity usage. monitor closely.
                              They are lightweight, they are not cheap.
                              Thanks for responding to my rants. It's difficult to make a right decision. There is a lot of misinformation on the net. People selling this stuff make it worse.


                              Comment


                              • #45
                                Originally posted by Mike90250 View Post
                                You are welcome to do your own research and come to your own conclusions. I'm being conservative. Put them in a safe place. Limit capacity usage. monitor closely.
                                They are lightweight, they are not cheap.
                                Thanks for responding to my rants. It's difficult to make a right decision. There is a lot of misinformation on the net. People selling this stuff make it worse.


                                Comment

                                Working...
                                X