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  • #16
    PNjunction,

    Thank you for taking the time to explain the details. I can be pretty binary about things..

    My folding panel set and the Optimate 6 arrived today and I confirmed with the local distributor that they have both the AGM 31 as well as the AGM 27 in stock. I could have picked them up today but they closed at 1:00pm and I didn't make the call till noon. I'll be making a run at lunchtime on Monday.. After your explanation I'm feeling pretty good that the panels, the Optimate 6 (thanks again, SunEagle), and one of the AGM batteries will do the trick.

    I just found the twelvevoltstore website.. I can see how this could be pretty addictive..

    thanks again,
    david

    Comment


    • #17
      Ok cool!

      I don't know if we've been over this before, but a quick reminder of *rested* soc values for most new agm's (4 hours or more, no load, no charge). Junky old sulfated batteries don't count.

      12.9v + 100%
      12.5v 75% <--- try to recharge to at least this level to help slow sulfation until you can get it truly fully charged...
      12.2v 50% <--- try not to go lower than this
      12.0v 25% <--- going this low on a regular basis just eats up your cycle life
      < 12.0v major hurt being put on battery. Even worse is if you let an inverter low-voltage disconnect activate as that is even lower!

      When you receive the batteries, put a voltmeter across the terminals. If they read much less than 12.4v, that means they have been sitting around in the manufacturer/distributor chain a long time. If they come really low, like at 12v, then I'd definitely reject them. Or, for this non-critical learning setup, let the Optimate recover it, and choose another distributor next time.

      Try not to use shirt-pocket voltmeters, or el-cheapo specials. There are a lot of options in the medium quality range. I personally use Fluke gear, and their low-end models 114/115/117 do just fine. There are many options, just don't go too cheap.

      Comment


      • #18
        Thanks again PNjunction.

        All points duelly noted and I have good tools to make the measurements.

        Keep the smoke in,
        david

        Comment


        • #19
          Originally posted by PNjunction View Post
          Ok cool!

          I don't know if we've been over this before, but a quick reminder of *rested* soc values for most new agm's (4 hours or more, no load, no charge). Junky old sulfated batteries don't count.

          12.9v + 100%
          12.5v 75% <--- try to recharge to at least this level to help slow sulfation until you can get it truly fully charged...
          12.2v 50% <--- try not to go lower than this
          12.0v 25% <--- going this low on a regular basis just eats up your cycle life
          < 12.0v major hurt being put on battery. Even worse is if you let an inverter low-voltage disconnect activate as that is even lower!

          When you receive the batteries, put a voltmeter across the terminals. If they read much less than 12.4v, that means they have been sitting around in the manufacturer/distributor chain a long time. If they come really low, like at 12v, then I'd definitely reject them. Or, for this non-critical learning setup, let the Optimate recover it, and choose another distributor next time.

          Try not to use shirt-pocket voltmeters, or el-cheapo specials. There are a lot of options in the medium quality range. I personally use Fluke gear, and their low-end models 114/115/117 do just fine. There are many options, just don't go too cheap.
          Did I cheap out too much on this one? http://www.amazon.com/gp/product/B00...rch_detailpage

          Comment


          • #20
            Personally, I would have chosen a unit that has true-rms, and also a min/max hold/record function.

            True rms for better non-sinusoidal waveform ac voltage measurements (msw inverters, etc.) and the min/max hold is extremely useful for tracking the charge algorithms and being able to easily discern what your absorb voltage truly is. Ie, making sure that when your charge controller is actually reaching the set values, or in some cases, if your CC or charger is merely attempting to finish absorb, but never reaches it, and falls back to float. Very handy unless you want to babysit the charge all the time vetting each new piece of gear.

            Accuracy specs are one thing. The real question is do you actually TRUST the Extech out of the box if you don't compare it to another reference standard, or higher end multimeter for peace of mind? If it does meet spec, how long will it do so? 1 year? 5 years? 20 years - like many Flukes do.

            There are many multimeters that will do the job, but like the charge controller, for me, a trusted reference like a Fluke that will stay trustworthy is invaluable for my solar setups. If I'm going to point the finger at something, none of it means much if I can't have even ONE thing I trust.

            Over the years, the "out of box" trust with Fluke has been established, and reconfirmed when I got a few of their low end 11x models since an 87V is kind of overkill for non-benchwork type stuff. And if anything, even though Flukes have +/- accuracy specifications, you'll tend to find them in the middle, and not at the edge of spec.

            Quick test - try doing some voltage measurements with both fresh and old heavily discharged batteries powering the multimeter. Do you notice any difference? Some of the cheaper units don't regulate voltage all that well when the batteries are going - even though they may not trigger the low-voltage warning in the display itself.

            I really don't want to get into a multimeter thread - plenty of those around. See Dave's EEVBLOG videos and MJ Lorton's videos about all the various models from low to high end if you really want to get into it.

            Comment


            • #21
              Originally posted by PNjunction View Post
              Personally, I would have chosen a unit that has true-rms, and also a min/max hold/record function.

              True rms for better non-sinusoidal waveform ac voltage measurements (msw inverters, etc.) and the min/max hold is extremely useful for tracking the charge algorithms and being able to easily discern what your absorb voltage truly is. Ie, making sure that when your charge controller is actually reaching the set values, or in some cases, if your CC or charger is merely attempting to finish absorb, but never reaches it, and falls back to float. Very handy unless you want to babysit the charge all the time vetting each new piece of gear.

              Accuracy specs are one thing. The real question is do you actually TRUST the Extech out of the box if you don't compare it to another reference standard, or higher end multimeter for peace of mind? If it does meet spec, how long will it do so? 1 year? 5 years? 20 years - like many Flukes do.

              There are many multimeters that will do the job, but like the charge controller, for me, a trusted reference like a Fluke that will stay trustworthy is invaluable for my solar setups. If I'm going to point the finger at something, none of it means much if I can't have even ONE thing I trust.

              Over the years, the "out of box" trust with Fluke has been established, and reconfirmed when I got a few of their low end 11x models since an 87V is kind of overkill for non-benchwork type stuff. And if anything, even though Flukes have +/- accuracy specifications, you'll tend to find them in the middle, and not at the edge of spec.

              Quick test - try doing some voltage measurements with both fresh and old heavily discharged batteries powering the multimeter. Do you notice any difference? Some of the cheaper units don't regulate voltage all that well when the batteries are going - even though they may not trigger the low-voltage warning in the display itself.

              I really don't want to get into a multimeter thread - plenty of those around. See Dave's EEVBLOG videos and MJ Lorton's videos about all the various models from low to high end if you really want to get into it.
              I bought it without really knowing what I was going to do with it, except for the very basic things. Like my $25 Harbor Freight inverter, I am glad I did not invest much before I started to research what I wanted to do .... which seems to change every month!

              I did struggle with one thing, that I can see the fluke would have helped with. I was very interested in what the NOCO charger was doing to my batteries and when, and also when the voltage dipped below what I calculated was 50% DOD during discharge. Do I understand you correctly that the record feature gives that sort of history?

              Comment


              • #22
                Originally posted by lkruper View Post
                I did struggle with one thing, that I can see the fluke would have helped with. I was very interested in what the NOCO charger was doing to my batteries and when, and also when the voltage dipped below what I calculated was 50% DOD during discharge. Do I understand you correctly that the record feature gives that sort of history?
                Yes it does, and brings up a very good point - the SPEED at which the multimeter can measure accurately, and also any under or over-shoot issues. The low end meters are typically not good at this, and if you use the min/max feature, you can be misled. Does the Extech seem to need time to "settle down"?

                Granted, fast transitions on a large bank take time - but that can happen pretty fast in absorb depending. If you later delve into LFP, or do other lithium-ion projects, then speed-with-accuracy here is vital.

                Example: when qualifying the Optimate 6 charger, which does an absorb by oscillating between 13.8 to 14.4v, a lesser quality meter with sluggish response or under / overshoot may read that it is oscillating between 13.2 to 14.1v for instance, leading to a false conclusion, a quick replacement which does the same thing and a bad online review.

                With a good meter, you can verify what a manufacturer is doing, or better spot something that is already on the edge of it's specifications. If the meter itself is at the edge of spec, or not fast enough to catch quick transitions, errors start to accumulate overall.

                More importantly, when seeking help in forums we are under the assumption that the measurements being reported are truly accurate, and if they are off somewhat, may lead to errant responses based on that, leading you down the wrong road.

                Does one need something like a Fluke 289 with it's recording abilities just to do the normal solar thing? I'd love one but can't justify it, although I am struggling to keep my wallet closed for that. In the meantime, my 11x series and the 87v as the ultimate reference do fine. I ignore the touch-hold function as the low-end series doesn't work the way it does on my 87v. So min/max is what serves my purposes best.

                Flukes aren't the only choice. I just don't want to endlessly test all the others or spend a lifetime doing research. For me, the Fluke's out-of-box performance and reliability just saves me a LOT of time.

                Note that there are models below the 11x series not usually intended for north american / european use - and like anything are built to a price-point and specs and features may start to widen. And as good as they are, USED old Flukes may be great, but you gotta' test them! Basically, I'm saying there is a limit, and starting new with nothing lower than a 11x series is your best bet - I'm not trying to hype the name across the board. My cute little model 101 is fine, and may beat out many cheapo shirt-pocket meters, but is not something I use to make critical measurements.

                Comment


                • #23
                  Originally posted by PNjunction View Post
                  Yes it does, and brings up a very good point - the SPEED at which the multimeter can measure accurately, and also any under or over-shoot issues. The low end meters are typically not good at this, and if you use the min/max feature, you can be misled. Does the Extech seem to need time to "settle down"?

                  Granted, fast transitions on a large bank take time - but that can happen pretty fast in absorb depending. If you later delve into LFP, or do other lithium-ion projects, then speed-with-accuracy here is vital.

                  Example: when qualifying the Optimate 6 charger, which does an absorb by oscillating between 13.8 to 14.4v, a lesser quality meter with sluggish response or under / overshoot may read that it is oscillating between 13.2 to 14.1v for instance, leading to a false conclusion, a quick replacement which does the same thing and a bad online review.

                  With a good meter, you can verify what a manufacturer is doing, or better spot something that is already on the edge of it's specifications. If the meter itself is at the edge of spec, or not fast enough to catch quick transitions, errors start to accumulate overall.

                  More importantly, when seeking help in forums we are under the assumption that the measurements being reported are truly accurate, and if they are off somewhat, may lead to errant responses based on that, leading you down the wrong road.

                  Does one need something like a Fluke 289 with it's recording abilities just to do the normal solar thing? I'd love one but can't justify it, although I am struggling to keep my wallet closed for that. In the meantime, my 11x series and the 87v as the ultimate reference do fine. I ignore the touch-hold function as the low-end series doesn't work the way it does on my 87v. So min/max is what serves my purposes best.

                  Flukes aren't the only choice. I just don't want to endlessly test all the others or spend a lifetime doing research. For me, the Fluke's out-of-box performance and reliability just saves me a LOT of time.
                  Yikes, what am I getting myself into? The 87v is $393 on Amazon which will probably be more than my first set of starter batteries. I think before I spend more money, I am going to make sure I know why I need it.

                  Comment


                  • #24
                    Exactly. The lower end 11x series is just fine for our needs - even if you go LFP.

                    Lots of inexpensive stuff is fine too - as long as you trust / test it. You might be the one who pulls the dud off the rack without knowing it unless you have another reference to check it with. And, do the new / old internal battery test too to see how well it regulates internally.

                    So one can cross their fingers, pull their hair out, or just spend a *little* more and not worry about it for the next 15-20 years.

                    Comment


                    • #25
                      Originally posted by PNjunction View Post
                      Exactly. The lower end 11x series is just fine for our needs - even if you go LFP.

                      Lots of inexpensive stuff is fine too - as long as you trust / test it. You might be the one who pulls the dud off the rack without knowing it unless you have another reference to check it with. And, do the new / old internal battery test too to see how well it regulates internally.

                      So one can cross their fingers, pull their hair out, or just spend a *little* more and not worry about it for the next 15-20 years.
                      I learned the lesson very early, still in school- tried to check Ohm's law using random ampere meter, voltmeter and some old resistor which turned out to have +- 20% tolerance(!). Well, I was pretty convinced the Ohm was wrong .

                      Comment


                      • #26
                        Regarding solar inverter

                        So here is my problem,
                        I hv installed a solar inverter along with battery(12v, 150Ah) and three solar panel(80 watt each). Main purpose is to provide power to an AC single phase induction motor of 373 watt with 1450 rpm. I am willing to run this motor on battery backup for around 2hrs, whenever there is power cut-off from the main grid. But it runs only for 5 mints.

                        Comment


                        • #27
                          Originally posted by kauboy View Post
                          So here is my problem,
                          I hv installed a solar inverter along with battery(12v, 150Ah) and three solar panel(80 watt each). Main purpose is to provide power to an AC single phase induction motor of 373 watt with 1450 rpm. I am willing to run this motor on battery backup for around 2hrs, whenever there is power cut-off from the main grid. But it runs only for 5 mints.
                          Your battery bank should be capable of supplying a total of 6000 watt-hours of energy at 100% discharge. You do not want to ever use a lead acid battery this way, so an available energy of 20% of that, 1200Wh, is reasonable. That should be enough to run you motor for more than three hours.
                          You are only getting about 30Wh going to the motor (373 watts times 1/12 hour).
                          The two most likely problems (assuming that the motor is good) are:
                          1. You battery is dead and has almost no capacity. Possibly is has not been properly charged.
                          2. The wiring is way too small to deliver the current needed by the inverter (at least 35A to let the inverter run the motor.)
                          SunnyBoy 3000 US, 18 BP Solar 175B panels.

                          Comment


                          • #28
                            Originally posted by inetdog View Post
                            Your battery bank should be capable of supplying a total of 6000 watt-hours of energy at 100% discharge. You do not want to ever use a lead acid battery this way, so an available energy of 20% of that, 1200Wh, is reasonable. That should be enough to run you motor for more than three hours.
                            You are only getting about 30Wh going to the motor (373 watts times 1/12 hour).
                            The two most likely problems (assuming that the motor is good) are:
                            1. You battery is dead and has almost no capacity. Possibly is has not been properly charged.
                            2. The wiring is way too small to deliver the current needed by the inverter (at least 35A to let the inverter run the motor.)
                            I have instaleed it three days ago. All purchases are new for best of my knowledge.

                            Comment


                            • #29
                              Originally posted by kauboy View Post
                              I have instaleed it three days ago. All purchases are new for best of my knowledge.
                              Did you charge up the battery first before testing?
                              Are you able to measure the battery voltage?
                              How big are the wires from battery to inverter? Compare the voltage at the battery terminals to the voltage at the inverter terminals.
                              SunnyBoy 3000 US, 18 BP Solar 175B panels.

                              Comment


                              • #30
                                Originally posted by max2k View Post
                                I learned the lesson very early, still in school- tried to check Ohm's law using random ampere meter, voltmeter and some old resistor which turned out to have +- 20% tolerance(!). Well, I was pretty convinced the Ohm was wrong .
                                Heh!

                                It's not really a case of multimeter brand snobbery. Maybe an anology would be like getting a hydrometer for your expensive new FLA battery bank from the auto-parts store sold right next to the pine-scented air fresheners. Maybe you'll get lucky. Or maybe not.

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