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So, lets spec out and set up a system of LiFePo4 batteries and inverter

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  • So, lets spec out and set up a system of LiFePo4 batteries and inverter

    As the title says lets put together a model system.

    I would like to get all the parts together to be able to do a test system. I would need everything - assume i have nothing. I need test instruments, and crimpers to make cables, strapping gear to strap up a set of 3.2v cells + anything you can think of one should have in a workshop to mess with LFP setups.

    Lets say i do a 24v system. That will be 8 x 3.2v Cells, say 100ah. Then i would use an Exeltech XP 600 watt inverter (this is just a small test system to get experience with).

    I would want to use mains power to keep the batteries charged. I would also like to use the same system hooked to solar panels - what CC should i use for that - one that can be optimized for LFP use or at least the config setup such that it can charge LFP batteries from solar panels.

    What charger would you suggest i use?

    What instrumentation could i use to have it talk back to a server (or some such setup) to log data of the system? This is useful if i wanted to put this in my weekend cabin but monitor from home during the week (Internet is available at the cabin) so i can see how much power is in the battery etc.

    What else am i missing that i need to think about getting so i can build out, setup and configure LFP systems?

    I would like to try a bigger system for full time off grid home use but would like to mess with a few smaller systems first to learn all the in's and outs.

    Thanks for any pointers
    Sammy Sparrow - a legend to Sydney radio listeners

  • #2
    No takers huh?

    Come on, this would be interesting - a parts list to build an LiFePo4 lab. Spec out all the parts one would buy in to setup a small LFP/Inverter/Solar Panel test lab so that one could practice setting up an LFP bank, practice bottom balancing, top balancing, BMS if one wanted to dabble in that etc.

    Its only a small system - 24v 100ah 600w inverter.....maybe 4 panels?

    Then have all the right meters and instruments to practice setting the batteries up to the various modes of operation.

    I have seen nothing like this anywhere - lots of chat about LFP but no actual mention of instrument part numbers or suppliers so one could put all this together.

    Does this have any merit at all or is it a stupid idea?

    If you want to learn Cisco routing, you put together a lab of Cisco routers, switches etc and then practice configuring it all. Why could this concept not work for LFP so us newbs can get up to speed on all this.

    I'd love to get into this and start experimenting and learning - but what parts? what tools do i need? which CC, which inverter?
    Sammy Sparrow - a legend to Sydney radio listeners

    Comment


    • #3
      In a hurry ? Give the coffee time to work before you demand an answer.

      Forget the mains/grid charger, for testing you won't need it.

      Look at the specs of your cells, the min voltage, and the max.

      There is also a voltage higher than the min, that if you go below, you have to only trickle charge, till you get above the slow charge threshold. No solar charge controller I know of, can do that, so you must have a LVD for the inverter when you approach that voltage.

      Midnight Classic and the Morningstar MPPT 45 & 60 I own, and have widely adjustable setpoints (so I can use them with my NiFe battery)
      Same with my XW inverter, has adjustable setpoints and LVD, so I could just drop in a LFP pack and tweak things.

      Another problem, is thermal. When cold, below freezing, you cannot charge the cells, so you need some sort of heater and charger interlock.
      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


      • #4
        24 volts @ 100 AH is no small learner system. That is over $1000 jus tin batteries in which you have no idea of what is needed to care for the. Most of the equipment you need does not exist, and would have to be built, or modify existing equipment to do something it is not designed to do.

        It is possible to use solar to charge LFP batteries. But there is only one Charge Controller made by GenaSun out there made for LFP and it is 12 volts at 10 amps or a single 120 watt panel. Until you know LFP batteries inside and out and have a couple years of experience, save your money and make your first set of destroyed batteries an inexpensive FLA or a handful of 18650 LFP cells. I guarantee you will destroy a $1000 set of LFP's real quick on ignorance.

        LFP is for pros who know what they are doing and can make or modify equipment to work with LFP. or folks who have more money they they know what to do with. It can be done, but not by many people.
        MSEE, PE

        Comment


        • #5
          Originally posted by Mike90250 View Post
          In a hurry ? Give the coffee time to work before you demand an answer.
          No not in a hurry - just 20 views no comment. The coffee percolator had run dry

          I guess in hindsight i could have said " is this a stupid idea and no one is therefore interested"

          It would be nice to have some help in assembling a small work bench of tools/meters , some chargers of different capacities (micro chargers for applying tiny chargers to a battery and a bigger battery that can put in some serious amps as/when the situation may require), cable making gear (where do i find a quality crimper - how do i even describe such a thing while looking for one .... a battery cable crimping tool?)

          A number of you here have all this stuff - what are the makes/model numbers - what do you like about them or why would you buy a different model if you were starting again etc?

          That sort of help. Maybe no one else out there is reading this forum and wanting to get started but is starting from zero and who wants to setup a work bench for messing with batteries? I do. I can peice together by trial and error if i have to, but would be nice to hear from the experts here. Thats all.

          But thanks for any input so far.
          Sammy Sparrow - a legend to Sydney radio listeners

          Comment


          • #6
            battery cable crimper = Hydraulic Crimp tool. About $50 on flea bay for a 10 ton version. If you are doing any work for hire, it needs to be the $400 tool with certified die paired to the lugs, or a failed connection lawsuit (house burns down) comes out of your pocket. There are some good pages / tutorials of what a good crimp is like, not overcrimped.

            Batteries - each brand/model has their own spec, so not knowing what you have, I gave no numbers.

            Don't forget the arc-quenching fuses (class T)
            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


            • #7
              It can be done easily - but one has to honestly judge their own competency and safety. It wouldn't be my recommendation as a *first* solar project.

              To make it easier, get the cells already in the voltage you need, and already properly strapped, banded, and cell-linked for you.

              ElitePower Solutions in Arizona who specialize in GBS cells have these. BatterySpace has them already built. Some amateur EV dealers sell them pre-built this way.

              If you want to go the manual route, Batteryspace also sells 3.7v "single cell chargers". Your local auto parts store has headlamps or smaller incandescents to make good dummy loads for the whole manual-balance thing. Or you can go with hobby-RC type chargers with balance leads.

              I've done the whole balance thing a few different ways with my cells for experimental purposes.

              You may want to read this sticky:
              http://www.solarpaneltalk.com/showth...rging-and-care

              It isn't really hard to go with an experimental LFP system, but it isn't for the guy next door, or as your first project.

              Comment


              • #8
                [PHP][/PHP]
                Originally posted by Mike90250 View Post
                There are some good pages / tutorials of what a good crimp is like, not overcrimped.
                Where ? URL's for this please.

                Batteries - each brand/model has their own spec, so not knowing what you have, I gave no numbers.
                I have nothing so far - not a thing. Starting at the bottom and want to build a decent work bench with whatever i need to be able to setup a few different systems to play with as i go along.

                Don't forget the arc-quenching fuses (class T)
                Yeah the fuses - a whole "side show" all to itself. Which ones do you recommend?
                Sammy Sparrow - a legend to Sydney radio listeners

                Comment


                • #9
                  Originally posted by PNjunction View Post
                  It can be done easily - but one has to honestly judge their own competency and safety. It wouldn't be my recommendation as a *first* solar project.
                  I hear you on that one !!

                  Actually it is YOU PNJUNCTION who has inspired me to go this way. I have read every post i can find of yours and have been for a while. I first saw you on other forums then saw you here and frankly i like this forum a lot. It gets a bit crabby at times, but the info here is GOLD.

                  I have read your posts encouraging people to have a try at LFP and setup small systems to play with and get experience on. As i have said many times now, i want to get serious about LFP and setup a workshop to build these batteries out. Its for my own use only, but i have a number of systems i could use. 2 houses at different ends of the country, plus an office in town, plus some other isolated projects i am involved in that could use backup power.

                  LFP may not be for everyone but there are huge advantages to me here in my specific situation, hence going forward to learn all i can and get the experience required to safely put these batteries together. No one was born an LFP expert - you all started somewhere. Now its my turn to get started. I am very interested in all this.

                  To make it easier, get the cells already in the voltage you need, and already properly strapped, banded, and cell-linked for you.
                  I am in Africa so not easy to get what i need. Hence wanting to put together a shopping list - i will need to get it all shipped in. I would much rather dig in at the deep end and do it all myself. That way, with sufficient supplies and stocks on hand, i rely on no one. Its the mindset you need out here in the bush in the middle of Africa if you are to survive.

                  ElitePower Solutions in Arizona who specialize in GBS cells have these. BatterySpace has them already built. Some amateur EV dealers sell them pre-built this way.
                  I am interested in making contact with the Chinese directly - its much more cost effective to get stuff shipped in from China to East Africa then it is for the batteries to come from the USA.


                  It isn't really hard to go with an experimental LFP system, but it isn't for the guy next door, or as your first project.
                  Understood - but some of us are die hards and want to know this stuff. I have no illusion its going to be easy but you can learn anything if you want too and have the "can do" mindset. I guess if i was one to shy away from challenges or things that are a little bit too hard, i wouldn't be living in the bush in the middle of Africa.

                  Solar is a well understood trade and easy enough to study if you want to get into all that (which i do). But the energy storage end of it all is where the rubber meets the road as far as i can see. Get the storage wrong and its very costly and the system is not that useful. So the storage that i see as the future, despite what one fellow here says all the time, is LFP. Maybe not for you all, but for some of us its an ideal battery tech.
                  Sammy Sparrow - a legend to Sydney radio listeners

                  Comment


                  • #10
                    I'll have to start a "sticky" thread for crimping.
                    meanwhile, here is a link to some lightweight crimping gear
                    http://www.pbase.com/mainecruising/b..._cables&page=1
                    http://www.pbase.com/mainecruising/wire_termination

                    There are some good examples of correct crimps, and examples of poor crimps.

                    remember, legally acceptable crimp connections use UL listed Lugs and their matching Die. The tool has a ratchet to prevent undercrimps.

                    Many shops use UL lugs, and whatever die fits. To be legal, the brands match and the die imprints a code on the crimp. Most hydraulic crimpers under $300 are capable of giving a good crimp, but don't have the imprint die.

                    try googling " hydraulic wire crimp tutorial " many sub-par videos, but a few good ones.

                    Solder has no place in a well crimped connection.
                    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


                    • #11
                      Originally posted by sammy_sparrow View Post
                      I am in Africa so not easy to get what i need. Hence wanting to put together a shopping list - i will need to get it all shipped in. I would much rather dig in at the deep end and do it all myself. That way, with sufficient supplies and stocks on hand, i rely on no one. Its the mindset you need out here in the bush in the middle of Africa if you are to survive.
                      Here is the problem. You are just as well off in the USA as Africa. Like any DIY the only batteries you have access to is Chi-Com POS LFP batteries like GBS and CALB. You cannot get the good stuff. Only EV and OEM's can get the good batteries.

                      Second problem there is no solar equipment made for Lithium batteries other than a small Marine Market using a single 140 watt panel. Great for a 12 volt toy using 12 volt 100 AH battery. Otherwise you wil have to use equipment made for EV's, and modify it to work with Solar. All of which voids all equipment warranties.

                      Playing with quality 18650 cells that cost $5 is one thing, playing with expensive cheap Chi-Com large format cells is a painful expensive lesson when you learn the truth about them and have to replace them every couple few years.

                      Lithium batteries are not ready for RE storage. Just way too soon. The fist to use them will be utilities. Bu tUtilities have to wait because the batteries do not exist yet. It is all prototypes and PR garbage to find find investors. Today Flooded Lead Acid is less expensive and last longer, and tons of equipment made to work with it. LFP will not be the future o lithium Batteries. Wrong chemistry. It will be either Lithium Titinate or some undiscovered annode/cathode material. Wait for it.

                      If you want to play buy some 18650 cells that cost $2 to $4 each and you only need 4 of them. Last thing you want to do is burn up $200 cells x 4 of them. If you need $800 of battery power from Lithium, a whopping 1 Kwh or enough top make a pot of coffee, buy a $400 FLA that will last at least twice as long for half the cost. It will not hurt as much when you destroy the battery.

                      Trust us, YOU WILL BURN UP YOUR FIRST BATTERY SET from negligence and ignorance. So which do you choose to throw in the fire place to burn? A $10 experiment battery or a painful $800 lesson you will regret.
                      MSEE, PE

                      Comment


                      • #12
                        SK,

                        So what happens with your big Pb bank that gets down to 50% SOC and the genset is "offline" for the next week or two? So much for Pb is cheaper then LFP now - right? So we can throw away our "cheaper" Pb bank when its ruined or its life shortened because it sat under charged for weeks. LFP will happily sit at low SOC for extended periods then charge right back up. This is the single biggest thing that makes LFP so valuable to me. Granted, bad situations "SHOULD NOT" occur.....but now come down to ground level and live life......Stuff happens! So i have to deal with it. How cheap is a ruined Pb bank compared to a more expensive to buy LFP bank that survives multiple "incidents" over a few years?

                        The other "biggie" for me is that LFP can take a huge charge. I can fill em up fast while i have the opportunity...which in my case, that charge opportunity may be gone in a few hours and not return till tomorrow...... or a few days later.....or sometimes even a few weeks later (worst we had so far was 3 weeks with no grid and a fuel shortage to go with it - a double wammy !!!) Stuff happens out here on the perimeter.

                        So you cant say Pb is best for every situation - its horses for courses. In my case LFP has some outstanding properties that make real sense to me. I understand they are not so useful to you. But that does not mean i should not look, learn, investigate. As for ruined battery banks - well its the cost of tuition I'm afraid.

                        Gee, i could write a book on what i have learnt the hard way out here. The most valuable lesson I've absorbed - "Cheap is expensive"
                        Sammy Sparrow - a legend to Sydney radio listeners

                        Comment


                        • #13
                          Sammy it can be done as I've pointed out.

                          It isn't all that drastic as long as one follow basic battery safety. And sounds like you've done a bit of homework.

                          The Chi-com batteries referenced will lead a pampered life since we aren't treating them to EV like usage environments. These batteries are good enough (GBS, Winston, CALB) for our mundane usage of them. Ironically, most anti-china viewpoints are expressed and read directly from Chinese home computers. And the op may well have a chinese high-end smartphone in their pocket. So not *everything* coming from China is automatically of poor quality.

                          The key here, whether you get them from a distributor, or directly from the mainland, is to get FRESH stock from a reputable place. Do not fall for new-old-stock, returns, bargain-bin offers, etc.

                          As an experimenter, you'll probably want at least a "single cell" charger, or perhaps a bench variable power supply with protection, like a Mastech "EX" series.

                          Before you jump in, I'm hoping you've seen Compass Marine's "Lifepo4 thoughts and musings" on lifepo4 battery building. It will give you a better idea of what you are up against starting out with bare cells and going totally diy.

                          I personally don't use any "balancing" on mine, other than the initial sanity check and frequent followup checks (much like a serious fla owner does with his hydrometer) but to each his own.

                          Comment


                          • #14
                            Originally posted by PNjunction View Post
                            Sammy it can be done as I've pointed out.
                            PNJ, as i have said, you are my inspiration for wanting to tinker. Your point of view resonates with me - completely.

                            It isn't all that drastic as long as one follow basic battery safety. And sounds like you've done a bit of homework.
                            A dose of common sense and dont try doing things you have no idea about - dont be shy to ask for guidance along the way - that's my point of view. I've done lots and lots and lots of reading over a year or two on batteries. I've got a few sets of AGM's running, both 24v and 48v. I've had mini AGM systems running to keep Wi-Fi AP's UP all the time as the power here goes off and on. I've got 24v AGM systems running communication systems at client sites. So some experience in general but not "technical" stuff like you talk about with meters and the like.

                            The Chi-com batteries referenced will lead a pampered life since we aren't treating them to EV like usage environments. These batteries are good enough (GBS, Winston, CALB) for our mundane usage of them.
                            Yeah i wonder about this. I've not read ANY posts anywhere about someone saying how bad their experience has been with LFP from the so called "Chicoms"

                            Ironically, most anti-china viewpoints are expressed and read directly from Chinese home computers. And the op may well have a chinese high-end smartphone in their pocket. So not *everything* coming from China is automatically of poor quality.
                            Totally agree. In general i dont buy Chinese. I always prefer the western product over the same Chinese product - but the line is blurring. As you point out much of the western stuff is made in China these days. I've had it explained to me here (as we get LOTS of Chinese stuff here) that you can buy 1st , 2nd and 3rd grade Chinses goods. If you want cheap the Chinese will oblige. If you want the best its also available out of China.

                            Thing is, if you want LFP, then you have little choice but to buy from CALB or GHB or Winston.

                            The key here, whether you get them from a distributor, or directly from the mainland, is to get FRESH stock from a reputable place. Do not fall for new-old-stock, returns, bargain-bin offers, etc.
                            I am going to look into shipping directly from China to East Africa. I most likely dont have anywhere near the volume required for the factories to deal direct with me, so not sure how this will work out.

                            As an experimenter, you'll probably want at least a "single cell" charger, or perhaps a bench variable power supply with protection, like a Mastech "EX" series.
                            HA HA ! This is what i need -
                            like a Mastech "EX" series
                            - i'll check them out.

                            Before you jump in, I'm hoping you've seen Compass Marine's "Lifepo4 thoughts and musings" on lifepo4 battery building. It will give you a better idea of what you are up against starting out with bare cells and going totally diy.
                            I haven't but will. In the end it doesn't really matter - it is what it is - and whatever it is i have to jump that hurdle. Our power situation out here is atrocious - LFP has some very real advantages in MY situation .

                            I personally don't use any "balancing" on mine, other than the initial sanity check and frequent followup checks (much like a serious fla owner does with his hydrometer) but to each his own.
                            On thing i have learnt here is to bottom balance and use a LVD. Thanks to SK for that ! I agree with his logic in this regard. This man, SK, knows what he is talking about - he just likes to argue a lot

                            PNJ, keep up the good work - i am sure there are a LOT of people out there who follow your posts - i do.
                            Sammy Sparrow - a legend to Sydney radio listeners

                            Comment


                            • #15
                              Originally posted by sammy_sparrow View Post

                              Yeah i wonder about this. I've not read ANY posts anywhere about someone saying how bad their experience has been with LFP from the so called "Chicoms"

                              It sounds like you have a pretty good BS filter. PNJ has the research and expertise to give you a good foundation on LiFepo4 to give you success and keep you out of trouble.

                              Comment

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