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Nickel Iron Battery - NREL Test Results

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  • #16
    Originally posted by Mike90250 View Post
    Please make the dropbox files available to the unwashed public.
    It (dropbox) wants me to log in to view them.
    I have no problem accessing it from the link right now. I have downloaded all three directories as zip files.
    SunnyBoy 3000 US, 18 BP Solar 175B panels.

    Comment


    • #17
      Originally posted by Mike90250 View Post

      Mike
      Willits, CA.
      Hey Mike, curious, didn't realize you were from Willits. You wouldn't happen to be my old neighbor, lived on the other side of Pine mountain, would you?

      Comment


      • #18
        Originally posted by Iron Bran View Post
        Here are a couple of systems using Nickel Iron batteries...


        [ATTACH=CONFIG]2693[/ATTACH]

        [ATTACH=CONFIG]2694[/ATTACH]

        [ATTACH=CONFIG]2695[/ATTACH]

        [ATTACH=CONFIG]2696[/ATTACH]
        So what is the rough installed cost for the typical 1.2kw home system?

        Comment


        • #19
          40 cells

          Originally posted by Mike90250 View Post
          After moldering along for 8 months, this thread wakes up.

          So, my off-grid experience living with NiFe batteries ( a large 48V, 800ah bank, single series string)
          is so far, mixed. I'm going through a lot of water, even in winter, with cloudy and short days. Shortly
          after sunrise, and way before the batteries get to absorb voltage, the battery shed sounds like a den of snakes, with all the bubbles hissing away. And when it hits absorb...... you nearly need earplugs.

          I have my major loads (large water pump for agricultural water) on a timer to only run on daylight hours, to not cycle the batteries, and do other load shifting, as anyone off grid would. So nights, the batteries are really only running the fridge and small amounts of lighting.

          Power has not gone out, but in cloudy weather, I've got a fair amount of generator run time, to keep
          the NiFe bank up, since it electrolyzes a lot of water compared to lead acid.

          So, I'm still reserving judgement, and when I have time, will break out the carbonate test kit, and
          see how the electrolyte is holding up.

          Mike
          Willits, CA.

          How many cells are you running?

          Comment


          • #20
            Originally posted by inetdog View Post
            I have no problem accessing it from the link right now. I have downloaded all three directories as zip files.
            I got it too, had to allow several scripts from different sites, to run.

            I'm not near Pine Mtn, I'm on the west side.

            I'm running 42 cells, with absorb set to 67.5V, which is just below my inverter max input voltage.
            I could disconnect the inverter and up the voltage another .75 volt, but I don't think it will help with the gassing.
            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 Mike90250 View Post
              I'm not near Pine Mtn, I'm on the west side.
              hahaha, didn't think you were the same Mike. Been 25 years since I lived up there.

              Comment


              • #22
                Originally posted by Mike90250 View Post
                I got it too, had to allow several scripts from different sites, to run.

                I'm not near Pine Mtn, I'm on the west side.

                I'm running 42 cells, with absorb set to 67.5V, which is just below my inverter max input voltage.
                I could disconnect the inverter and up the voltage another .75 volt, but I don't think it will help with the gassing.
                Has anyone tried using condensing battery caps to cut down on watering?

                I have had experience with nickle-iron, but not in solar. Years ago I worked in a DuPont polyester plant. Job involved use of electric forklifts (special built for job, about 4 times the size and weight of normal propane ones and spent the shift moving 10,000lb containers around) that ran on 2 nickle-iron batteries, about 3ft high, 3ft long and 1ft thick. We would install new ones at start of shift and run them for 8 hours. By end of shift could tell they were getting low and sometimes had to used one to tow a dead one into the changing room. So guess you could say we drained them dead regularly. We did have to top of the water in the used ones after instilling the fresh ones, best I recall was only maybe a pint or so per battery. Plant run 24/7/365 and each set got used once per day. I was there for 2 years and never noticed any drop off in performance and the batteries had been there long before I started. I'm planing a new house and will be off-grid and I am very seriously thinking of using Nickel-iron. I plan on being around another 30years or so and want the systems in the house to do the same and not have to spend a large pile of mony replacing things like batteries.

                Comment


                • #23
                  Originally posted by mtman8 View Post
                  Has anyone tried using condensing battery caps to cut down on watering?
                  ......
                  There are 2 types, one with "plastic beads" in them, that intercept the "mist" and let it drip back into the cell. The other type has a platinum mesh (like steel wool) inside, that recombines the H & O2 back into water, and lets it drip back in. I think the electrolyte (alkaline) will destroy the platinum.

                  Neither type has the air check ball valve that helps exclude Co2.
                  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
                    The other type has a platinum mesh (like steel wool) inside, that recombines the H & O2 back into water, and lets it drip back in. I think the electrolyte (alkaline) will destroy the platinum. .
                    Mike you are correct. Platinum is a Noble metal like gold. However like gold It does not oxidize in air at any temperature, but unlike gold, platinum is corroded by cyanides, halogens, sulfur, caustic alkalis and acids.

                    FWIW the USN uses a lot of platinum in submarines.
                    MSEE, PE

                    Comment


                    • #25
                      I have been thinking of upgrading our entire 12 volt nicad 180ah system to a 1000 watt 600 ah nickel iron set up. Zapp works is more expensive than Iron Edison. Is it not true that you can't run these down 80% without damage? I thought you could? I would expect loss of distilled water, which can be replaced relatively easily. Please correct me if I am wrong. I would like to move from the propane servel to a sundazer or other efficient 12 volt refrigerator or freezer or both, run some radios, laptops, and a couple of lights. Does anyone with experience nickel iron batteries have some input for me? I am new to this and building on my father's design.

                      Comment


                      • #26
                        Montezuma,

                        First and foremost.... Can you drain NiFe batteries down to 80% without damage? That's a relative question that invites lots of opinions, but the better question is..

                        "Can you run them down to 80% and not void the warranty?"

                        That answer I believe to THAT question is NO. I think you are limited to drawing them down to a specific voltage. How much of the capacity that is compared to a 100% draw down I will leave for others to answer as I really don't know off the top of my head.

                        Also, you ask for real life experience? You are talking to the right guy when you converse with Mike. He's living the NiFe "dream" .


                        For everyone....


                        Might was well post this here as others might find this interesting. All this information is from an old 24v setup of C6 Edison cells I've had in service for the past year or two, and haven't really documented much of what I learned as the discussions were perhaps "too hot" and the value might get lost in the noise. I emphasize, the information that follows is from my own personal experience with these older cells. Exactly how that translates to the current cells on the market, I do not know for sure - but I feel as though a lot of the basic learning should be the same.

                        To start with, I found this to be my "charging equation" after reconditioning the cells:

                        E = 1 - EXP((A-C)/100)

                        where:

                        E = Charge Efficiency Factor
                        C = Battery Capacity in Amp Hr
                        A = Battery Current State (Amp Hr) at start of charge

                        For my cells, the value of C was found to be 358 over a series of investigations. I find it interesting that my C value is very close to Edison's published value of 365, but only state that I find it interesting. I cannot defend the mathmatics of the similarity of the values on any theoretical basis other than 365 will be the maximum charge that I can pack into my battery bank.

                        Using this equation as reference, you can see that if I use only the top 20% of the battery capacity, my coulombic efficiency is only about 50%. When I run my batteries in the bottom end of their range, I am achieving coulombic efficiencies in the 90's, but how long I can keep up those cycles before I must again recondition them I cannot yet be certain. Important to state again - the NiFe battery warranties I have seen will not allow you to do this and keep your investment covered by their warranty. I am NOT advocated you run like this, but since I've only got $600 invested in my cells and I'm a curious sort, I am free to push them however I like to learn more about the NiFe technology.

                        A few things worthy of note...

                        (1) Coulombic Efficiency does NOT equal Watts In versus Watts Out. NiFe batts charge at a very high voltage relative to their discharge. If I put 100 amps in at 1.6 volts and pull those same 100 amps out at 1.3 volts, that's only 81% efficient on power recovery even though I might be 100% efficient in coulombs. Also, the harder you pull on a NiFe the lower the voltage will be (i.e. voltage sag). Therefore the more instantaneous watts you draw, the lower the overall efficiency you will experience from the battery. This is worse for a NiFe than a traditional LA cell due to higher internal cell resistance.

                        (2) Water loss is a given with NiFe... According to the Nernst equation for splitting water, the water loss due to electrolysis can occur with as little as 1.23 volts across the cell. Truthfully speaking though, you gotta give it a bit more of a nudge to get over the threshold hump for the electrolysis reaction to proceed so it's really more like 1.48 volts that splits the water in the cell. That's great for a lead acid cell as we typically charge just a little lower than this, but unfortunately for NiFe we use higher voltages. For example, Mike said he absorbs at about 67.5 on a 48 volt bank - or about 1.68 volts per cell (assuming he's got 40 cells). If he absorbed at a lower voltage he'd use less water - but he'd also not pack the cells as full / fast. Unfortunately, that's just the way it is with NiFe.

                        (3) Misting... At least with my C6 "bubble tops", misting is a real issue - even more so than water electrolysis (I absorb at 1.60v per cell as my bank is now in UPS service). The mist that comes out of the batteries with the H2/O2 off-gassing settles back down and creates a highly alkaline, corrosive "dust" on the tops of the batteries. I have to wash these off every so often.

                        Other things worthy of note that I've learned but have not seen stated elsewhere....

                        (4) Iron Poisoning... Yeah, yeah, yeah... Lot's of noise about this, but what the heck is it? From what I've seen in my testing, there are two major sources of it. (A) When the battery is in the charged state, iron from the anode is corroded by the alkaline electroltye and can be deposited back on both the anode and cathode plates. This does not occur so much when the battery is only partially charged because the iron is in the form of iron oxide (not subject to alkaline corrosion), but who wants an uncharged battery?

                        The largest problem I observed in the C6's when I reconditioned them was that (B) some of the iron oxide formed on the anode during discharg had sluffed off and fallen to the bottom of the cell. Perhaps you've heard about "carbon" in the bottom of these old cells? Rubish!! That's black iron oxide. None too good to have it fall from the anode, but even worse when it builds up to the point that it shorts out the cell. This is certainly minimized in the solar use of these cells as they are stationary, but it might still well occur.

                        (5) Carbonate Formation.... well first let's talk about, "Why use potassium hydroxide and not the cheaper sodium hydroxide?"

                        I thought maybe the potassium was a better choice than the sodium due to it's increased reactivity, but BOTH perform essentially equally well in a NiFe cell, and I wouldn't spit for the difference in the power curves I've seen. KOH is still my preferred choice though. Since NaOH is like half the price (or less) than KOH, then why do I consider KOH to be a better choice? It has to do with the "flavor" of pesky carbonate that is be formed. Potassium carbonate is greater than 5x more times soluble in water than sodium carbonate and you don't want kickout in your cells or the power performance will be adversely affected (i.e. increased voltage sag at respectible draw rates or even worse - cells shorting out). If you use potassium hydroxide (KOH) as your hydroxide source, the resultant potassium carbonate is soluble at about 50% by weight in water.

                        (6) What's the issue with carbonate formation if it doesn't kick out? - aka "Much ado about carbonate"

                        The presence of the carbonate itself isn't really that big of an issue. I've done studies with and without potassium carbonate being in the cell, and in reasonable concentrations it just "goes along for the ride". The biggest issue we have to deal with is that in our cells as carbonate increases in concentration, it indicates consumption of the hydroxide. Hydroxide is necessary for the NiFe redox reactions to proceed. Too lean of a hydroxide content and you will experience decreased reaction rates which can cause abnormally high voltage decrease while pulling out the stored amps and/or decreased charge efficiency when charging at high rates. Once you are at the "critical content" of hydroxide in the cell, further increases in the OH content will not improve cell performance as other factors will take over controlling the maximum discharge rates. Rather than simply worrying about carbonate, we really need to be concerned with the "Free KOH" content (assuming you are using potassium hydroxide as your base source). I measure "free KOH" by taking a sample from the cell and crashing out the non hydroxide species with Barium Chloride (i.e. make the insoluble Barium Carbonate). After filtration, all titrated species will then be hydroxide and thus we get the free KOH measurement. If / when the hydroxide is consumed it can be replaced by adding concentrated KOH back into the cell. What I've found is that if you keep your free KOH up above the critical level, the cells do not loose performance unless kickout occurs.

                        NOTE: In stationary cells such as ours, you should NOT be forming carbonate at a very high rate at all. The vapor phase above the cell liquid should be mainly hydrogen and oxygen due to the hydrolytic cracking of water side reaction that goes on during charging. If you ARE forming carbonate at too high a rate, you need to investigate why. Main thing I'd be looking at is heating and cooling of the battery causing it to "breathe" gas in and out thus pumping CO2 into the cell. Sure, you can use a "float" on the surface to minimize this formation, but I'd rather it not be a carbon based material (i.e. mineral oil) as that too can be converted to carbonate during charging. My decision was to use no float at all. Carbonate has not shown itself to be an issue for me (yet).

                        I hope this helps some people out - if nothing else perhaps feeds their curiosity. I'm certainly not claiming to be an expert on NiFe technology. Just simply sharing some observations / data I have collected.

                        Comment


                        • #27
                          Originally posted by Robert1234 View Post


                          (3) Misting... At least with my C6 "bubble tops", misting is a real issue - even more so than water electrolysis (I absorb at 1.60v per cell as my bank is now in UPS service). The mist that comes out of the batteries with the H2/O2 off-gassing settles back down and creates a highly alkaline, corrosive "dust" on the tops of the batteries. I have to wash these off every so often.
                          I am using neoprene stoppers with a 4mm hole in the center as a substitute for the "bubble tops" Insert 4mm PFE/A tubing in the stopper and vent to a 1G water container nearly filled. No more cleaning of the cell tops required. It acts as a trap for CO2 also. The trap effect worked great in warmer weather but siphoned back a couple times in cooler weather. I think adjusting tube height will correct this. One source is General Lab Supply in Pasadena, Tx. Part number that works great on an Edison C6 is PLS R6300-1. Thanks for sharing your NIFE information.

                          Comment


                          • #28
                            That's a neat way to address the issue. I have thought about doing things similar, but just haven't followed through. Since you've proven out the concept already, maybe that'll inspire me to get off my butt and install the solution. Thanks

                            Comment


                            • #29
                              hmm

                              Originally posted by Iron Bran View Post
                              Here are a couple of systems using Nickel Iron batteries...
                              pics pics and pics
                              Mod note - no need to copy picture.
                              Last edited by russ; 11-21-2014, 06:32 AM.

                              Comment


                              • #30
                                Originally posted by Robert1234 View Post
                                Montezuma,

                                First and foremost.... Can you drain NiFe batteries down to 80% without damage? That's a relative question that invites lots of opinions, but the better question is..

                                "Can you run them down to 80% and not void the warranty?"..........
                                Thank you Robert, for this great post.
                                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

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