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  • #16
    I am not sure why you would want a 36 volt inverter. This is not a standard setup at all. I have several hi capacity 24 volt banks of batteries and use one Classic 150 charge controller on each bank. One charge controller is fed with an array of 72 cell "24" volt panels which have a MPP of 36 volts. These are wired 2S6P , a series connection that produces about 72 volts at MPP. The classic converts this 72 volts down to the 24 to 30 volts needed to charge the battery. The other nearly identical system has 96 cell 53.5 volt @MPP Sanyo HIT multilayer panels wired as all parallel. 12P . Again the Classic converts this 53.5 volts down to the 24-30 volts needed to properly charge this battery bank.

    If if you will notice......The array output voltage is >two times battery voltage......this is what is required to properly charge a FLA battery set with an MPPT....(Maximum Power Point Tracking) controller

    Also please note.......The batteries are NOT IN PARALLEL.......they are separate systems that can be paralled but are kept separate as parallel sets of batteries are problematic. I have 100% redundancy in a super reliable system....no fails, no brownouts, no system shutdowns , I have never had a LVCO (low voltage cut off) where the system shuts down cold due to discharged batteries. I have no utilities at all and do depend on my systems being super reliable as I use some power medically which is totally out of the scope of this forum.

    Please note......I am not here to criticize how someone else does things......I share my expereince doing what has been proven to work. If you disagree with me, then that's fine, I won't argue the issue. There are things that you have done that I would not do in any case.

    My background......born in the backwoods of Alaska, learned how to do with very little back in the 50's, a born off gridder...LOL I'm off grid because I know that I can do it!

    My suggestion for you...Get a decent charge controller and inverter, do a 24 or 48 volt system, keep it standard and listen very well to the good advise and you will get good help, ......be argumentative and folks will avoid you.....don't take that personally!...no really do take that personally........I don't mean that offensively.....

    david

    Comment


    • #17
      Originally posted by onesmallonebig View Post
      Really? Maybe that's why I cant get my four 36v battery banks to charge higher than mid 38 volts with these panels and it takes forever (days) to charge them back up.
      That's what Littleharbor was getting at up there when he referred to your panels as "24V" panels. "12V" panels are 36 cells, yours are 72 cells which is twice the number, twice the voltage, and therefore a good match for a 24V battery. Your mistake was looking at Vmp thinking that was the battery voltage that the panel was designed for.
      Last edited by sdold; 06-13-2019, 06:13 PM.

      Comment


      • #18
        Originally posted by Tecnodave View Post
        Have you stopped to consider that a 36 volt battery bank will need at least 43-45 volts out of the controller and with an MPPT controller that will require about 60-70 volts into the controller to maintain that 43-45 volts out!

        Also please note that a 220 volt inverter is not a split phase 120/240 volt inverter.........they are not interchangeable!
        Okay Dave, so with my six 36v panels I'm going to wire two panels together in series and make three 72v mini arrays. Then hook those three up in parallel for one big 72v array?

        Thanks for your advice.
        James

        Comment


        • #19
          Originally posted by sdold View Post
          That's what Littleharbor was getting at up there when he referred to your panels as "24V" panels. "12V" panels are 36 cells, yours are 72 cells which is twice the number, twice the voltage, and therefore a good match for a 24V battery. Your mistake was looking at Vmp thinking that was the battery voltage that the panel was designed for.
          I realize that now. I couldn't understand what the guys were saying. I'm dumb. I was trying to match all the numbers. Didn't know I needed twice as much to get half as much lol. I was growing older watching the 36v battery bank recharge at 1/10 of a volt a day lol.
          I'm stuck with this 36 volt system now. I have six 36v panels, two 36v inverters and a one size fits all MPPT. These 6 $80 each used 36v/310w panels have become a PITA. But Im learning.

          At least my 12v system "seems" to be working good so far. I'm not touching it. I did steal three batteries from the dysfunctional 36v system, so the 12v system has 10 batteries now. It's running everything about 50% of the time all by itself this week. At sunrise its about 11.5ish and by sundown its back up to 13.4ish. Is that good or bad?

          Comment


          • #20
            > by sundown its back up to 13.4ish.

            What is the battery voltage an hour after sundown? Generally, 14.5V is a good charging voltage for daily cycles. 13.4 seems a bit low. Remember, charging voltage needs to be several volts above the battery resting voltage.

            battery-state-of-charge LeadAcid.jpg
            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


            • #21
              Originally posted by Tecnodave View Post
              I am not sure why you would want a 36 volt inverter. This is not a standard setup at all. I have several hi capacity 24 volt banks of batteries and use one Classic 150 charge controller on each bank. One charge controller is fed with an array of 72 cell "24" volt panels which have a MPP of 36 volts. These are wired 2S6P , a series connection that produces about 72 volts at MPP. The classic converts this 72 volts down to the 24 to 30 volts needed to charge the battery. The other nearly identical system has 96 cell 53.5 volt @MPP Sanyo HIT multilayer panels wired as all parallel. 12P . Again the Classic converts this 53.5 volts down to the 24-30 volts needed to properly charge this battery bank.

              If if you will notice......The array output voltage is >two times battery voltage......this is what is required to properly charge a FLA battery set with an MPPT....(Maximum Power Point Tracking) controller

              Also please note.......The batteries are NOT IN PARALLEL.......they are separate systems that can be paralled but are kept separate as parallel sets of batteries are problematic. I have 100% redundancy in a super reliable system....no fails, no brownouts, no system shutdowns , I have never had a LVCO (low voltage cut off) where the system shuts down cold due to discharged batteries. I have no utilities at all and do depend on my systems being super reliable as I use some power medically which is totally out of the scope of this forum.

              Please note......I am not here to criticize how someone else does things......I share my expereince doing what has been proven to work. If you disagree with me, then that's fine, I won't argue the issue. There are things that you have done that I would not do in any case.

              My background......born in the backwoods of Alaska, learned how to do with very little back in the 50's, a born off gridder...LOL I'm off grid because I know that I can do it!

              My suggestion for you...Get a decent charge controller and inverter, do a 24 or 48 volt system, keep it standard and listen very well to the good advise and you will get good help, ......be argumentative and folks will avoid you.....don't take that personally!...no really do take that personally........I don't mean that offensively.....

              david
              Sorry Dave, I keep missing posts. There's a page 2 button. This is my first forum in a long time. I dont go on twitter or facebook, etc either. Love youtube though. free old movies.
              <I am not sure why you would want a 36 volt inverter.>
              I thought I needed a 36v inverter to "match" the 36v panels I bought. Oh well, now I have two 36v inverters lol. 2S3P panels soon.
              <parallel sets of batteries are problematic>
              I'm running 3S3P (stole 3) now with my battery bank to get 36v to the two 36v inverters I'm stuck with. Good? Bad? Or should I go with 3 MPPT charge controllers. One on each 36v bank, two panels in series to each controller?
              I dont mind buying more stuff, but I want to use the stuff I already have.

              Except for the freezing temps up there, you are my off gridder hero. I turned down an offer to weld the pipeline in the late 70s because it so cold up there.... all the time.
              Too late for standard. One 'good" controller and inverter costs more than both of my systems combined.
              I think the arguers are finally done. We got past ghost electricity, Energy Star, battery cables, sales pitches, keyboard warriors, I did everything wrong, etc.
              This is what I got to work with and this is what I want to do. If you can give me any advice on how to do it better within those parameters, I'm all ears. Just explain it to me like you are talking to a 5 year old

              James


              Last edited by onesmallonebig; 06-15-2019, 03:24 AM.

              Comment


              • #22
                Originally posted by Mike90250 View Post
                > by sundown its back up to 13.4ish.

                What is the battery voltage an hour after sundown? Generally, 14.5V is a good charging voltage for daily cycles. 13.4 seems a bit low. Remember, charging voltage needs to be several volts above the battery resting voltage.

                battery-state-of-charge LeadAcid.jpg
                I'm not even sure how to see the charging voltage.
                My 36v systems is offline til I rewire it in series. It started at 38.8v and kept creeping down 1/2 volt per day. I shut it off at 35.7. its only back to 36.3 now. But thats all changing tomorrow.
                My 12v system has been nonstop for two months. It gets to 13.8 sometimes in the early afternoon and I panic and tilt the panels away from the sun lol. The automatic kill switch is 14.1 by default.
                I'm thinking if its in the high 12s then I'm good. Wrong huh? It has hit 11.1 twice and I shut it down. A friend came over those two times and i was too busy to keep an eye on it. If you know what I mean.
                An hour after sundown and most of the evening its in the mid 12s. Then it starts creeping down to the mid 11s about 4am. Right now at almost midnight its.... BRB.... 11.9v. But the fridge was running and I made a pot of coffee too. I just shut off the fridge for the night. Just the TV, satellite box, laptop and a 30w LED lamp for the rest of the night.
                Nice chart, alright new goal 12.37v 70% minimum on the 12v system. I'll let it hit 14.1 for now on. Where's the non-standard 36-V bank column? lol 37.11? 3 times 12.37.
                Last edited by onesmallonebig; 06-15-2019, 03:22 AM.

                Comment


                • #23
                  Remember, that chart is for resting voltage, 12V flooded batteries generally need 14V or more to charge in the limited daylight hours. (so the 36v bank needs 42v if your panels can provide that)

                  I'm really sorry you are stuck with mismatched gear.
                  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


                  • #24
                    Originally posted by Mike90250 View Post
                    Remember, that chart is for resting voltage, 12V flooded batteries generally need 14V or more to charge in the limited daylight hours. (so the 36v bank needs 42v if your panels can provide that)

                    I'm really sorry you are stuck with mismatched gear.
                    Thanks Mike, Okay 42 to 42.5v resting (no load at night?) it is.
                    I'm getting there slowly but surely. I tested the 72v system 2S3P for the first time today with 3s3p batts. At 10am, I hit these numbers under load (fridge, TV, satellite box, garden pump). Of course I panicked, took two pics, and flipped the panels away from the sun. Eventually I flipped them back and let whatever happens happen but checked it every 15 minutes all day long. Seemed to be working fine.Both fans were going most of the day. And the MC4 connectors felt warm. Highest temp I saw was 53C when I panicked. I was driving myself nuts looking at the numbers so I quit looking. But the PV hit 80v several times. When the batts hit 42 something, I assume the CC defaults reduced its output to 375w to match the load I was using? Before sundown, it was about 1100w output and about high 41s.
                    I shut the system off at sundown. Tomorrow, I'm gonna test more loads, the swamp cooler., tank water pump, jucuzzi pump... not at the same time.
                    Attached Files
                    Last edited by onesmallonebig; 06-20-2019, 03:20 AM.

                    Comment


                    • #25
                      Before something expensive cooks - What are your batteries ? I didn't see mention of them earlier. Flooded are pretty forgiving, but if you are using AGM, they have very strict voltage specs that need to be observed.
                      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


                      • #26
                        Originally posted by Mike90250 View Post
                        Before something expensive cooks - What are your batteries ? I didn't see mention of them earlier. Flooded are pretty forgiving, but if you are using AGM, they have very strict voltage specs that need to be observed.
                        19 Group 29 Deep Cycle 12V Marine/RV/Boat FLA batteries. Right now, 9 on the 72v system and 10 on the 12v system.
                        I know I know, the worst possible batteries on earth I can use lol
                        Last edited by onesmallonebig; 06-20-2019, 03:55 AM.

                        Comment


                        • #27
                          Originally posted by onesmallonebig View Post

                          19 Group 29 Deep Cycle 12V Marine/RV/Boat FLA batteries. Right now, 9 on the 72v system and 10 on the 12v system.
                          I know I know, the worst possible batteries on earth I can use lol
                          10, 12 volt batteries in parallel? Not necessarily the worst batteries but one horrible configuration.
                          2.2kw Suntech mono, Classic 200, NEW Trace SW4024

                          Comment


                          • #28
                            Originally posted by littleharbor View Post

                            10, 12 volt batteries in parallel? Not necessarily the worst batteries but one horrible configuration.
                            I still have nightmares from the first time you told me that LH
                            It was the only thing I had actual working for the last two months. I even had 12 batteries in parallel for the first month lol
                            In my defense (mercy of the court), I spread the love, CCs. I'm using 3 PWM 12v CCs. One on battery #1, one on battery #5 where the 12v/110v inverter is, and one on battery #9. My theory is, "Everybody gets some." I didn't change any of the default CC settings.
                            When they drop to 12v I'm NOW shutting off the inverter. And I'm no longer flipping the panels at 13.8v and just letting them fry (charge). I did let the voltage drop to 11.1 twice, my bad,
                            Also horrible is 9 panels in parallel... I have three 17v Vmp (thanks to you LH I know what that means) panels hooked to each CC in parallel. More love spreading.

                            Okay, now that the 72V system is FINALLY up and RUNNING and working good, thanks to you guys, let the 12v system reconfiguring begin...
                            The system MUST stay within these parameters...
                            1. Must be a separate stand alone system.
                            2. Must use most of MY 9 50w panels and no more than 12 50w panels (I'll buy up to 3 more, if necessary). That's all the room I have on my tracking frame to mount more small panels.
                            3. Must use most of MY 7 12v batteries and no more the 10 (I'll buy up to 3 more, if necessary). I'm stealing three of the 10 batteries currently on the 12v system to put "back on" the 72v system in series.
                            4. Only buy one new MPPT CC
                            5. Only buy one new 1500/3000w inverter.
                            6. No questions about my load demands or my battery cables lol

                            I'm all ears.

                            My idea...
                            My panels in 3s3p, my 3s3p battery bank, my 36v to 220v pure sine inverter "stepped down" to 110v, buy a 36v CC. Horrible?











                            Comment


                            • #29
                              24 hour typical load test
                              All numbers are at the inverters
                              72v, 12v systems
                              -----------------------
                              2pm: 42.7v, 14.8v
                              ----------------------
                              6pm: 42.6v, 14.8v
                              ----------------------
                              11pm: 37.9v, 13.6v
                              ----------------------
                              2am: 37.2v, 13.3v
                              ----------------------
                              430am: 36.5v, 13.0v
                              ----------------------
                              7am: 41.4v, 13.3v
                              ----------------------
                              8am: 42.5v, 14.0v
                              ----------------------
                              10am: 42.4v, 14.5v
                              ----------------------
                              noon: 42.5v, 14.8v
                              ----------------------
                              2pm: 42.5v, 14.8v

                              Good? Bad? So so? Horrible?

                              Last edited by onesmallonebig; 06-21-2019, 05:53 PM.

                              Comment


                              • #30
                                Here's the best setup I can come up with for the 12V panels.
                                Only have to buy a MPPT CC and step down converter.
                                And, I'll have and extra 12V/50W panel, 3 12V CCs, a 12V/110V Inverter, and a 12v battery to play with.
                                Is this more like how I'm supposed to do it?
                                Attached Files

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