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LiFePO4 - The future for off-grid battery banks?

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  • Originally posted by TroyDog View Post
    ... Charge controller has a user type battery selection mode, plug a laptop into it and you can set the bulk\float voltages. As there are no readily available Lifepo4 solar chargers off the shelf, this one seems ok and with bulk voltage set to 13.8, float set to 13.2 it charges the 12 volt battery quite well ....
    Hi Troy - welcome! That is a reasonable setting for solar. Assuming your bank is balanced, bulk to 13.8v just to the start of the upper charge knee is wise. And at 13.2v for float (which lifepo4 doesn't need), that is a benign setting since essentially nothing is happening, and the voltage is well under 13.8. Be sure you have DE-activated any sort of temperature compensation!

    That controller may be confused if you did not attach the batteries first, and THEN the panels. Do it the opposite way, and they can become confused. But seriously, I would not hang an iPanda controller in front of my lifepo4 bank. At this stage of the game, name brands with a history of reliability are important, but that's me.

    the BMS is very configurable from its front panel display and is set for low cell = 3.0, max cell = 3.6 and balance voltage = 3.50. With these settings in this setup taking into account circuit breaker\fuses\cables voltage drops, the solar charger switches to float mode at cell voltages approx 3.55 in the region where the balance boards across each cell start to activate.
    Once balanced, you shouldn't need to rebalance them again, or risk the additional points of failure of the bms. We get these cells predominantly from the EV industry, where high-voltages, high-currents, massive series-parallel wiring infrastructure, and the desire to squeeze the last drop of blood from them frequently takes them to abusive levels.

    We on the other hand are running a simple 4S bank (mine are GBS cells), with relatively low voltage, and low current needs and a simplified wiring infrastructure. Other than an HVD (your charge controller), and an LVD, the balancing function of the BMS can become more of a liability than an assett. Essentially, in a low-C environment, once balanced they will stay in balance. Just stay out of the charge / discharge knees. When I measured my capacity, I easily exceeded the capacity ratings by only staying within the knees.

    Consider that your present controller will not ever take the batteries to the point where the bleed balancers operate. So my recommendation is that if you have proven to yourself that the bank is staying in balance with the controller set as it is now, (about no more than 0.050v, or 50 millivolts spread after a few hours rest after taking them to 3.55v each) you may want to remove the bms if you are solely using it for balancing, and have other measures for HVD and LVD.

    Many outside our service application from the motive-power industry (be it EV, Ebike or RC modeling) spell doom and gloom unless you hang a rats nest of wiring over a simple 4S storage bank. If it is balanced, then just do sanity checks on it once in awhile, rather than letting a bms fail, and inadvertently ruin your bank.

    Comment


    • Getting ready to replace lead acid battery Bank

      Interested in this thread for LiFePO4 for replacement of Lead Acid Battery Bank and would like to see the pictures.

      Comment


      • Originally posted by Iron Bran
        ........
        Interesting way of using this forum for your advertising.

        Comment


        • Originally posted by SunEagle View Post
          Interesting way of using this forum for your advertising.
          Right - a first time poster asking for photos - oh well, they are now gone.
          [SIGPIC][/SIGPIC]

          Comment


          • Moderator

            Originally posted by russ View Post
            Right - a first time poster asking for photos - oh well, they are now gone.
            This first time poster is not asking for photos but wants to see photos that are posted and being moderator I take it that you know that you need to make a post in order to view them ouch.

            Comment


            • Are you replying to me ?

              Originally posted by SunEagle View Post
              Interesting way of using this forum for your advertising.
              From Russ's answer I take it this is for me but tell this first time user how would I know that that 184 Post is for me?

              Comment


              • Originally posted by discovery5 View Post
                From Russ's answer I take it this is for me but tell this first time user how would I know that that 184 Post is for me?
                No. I was not referring to you but to Iron Bran who provided 4 pictures of a battery system that I believe he is trying to sell.

                I have no issues with someone providing information or a place to look at specific hardware but I believe anyone that posts hardware that they sell should first get approval of the Solar Panel Talk forum owners.

                Comment


                • Originally posted by SunEagle View Post
                  No. I was not referring to you but to Iron Bran who provided 4 pictures of a battery system that I believe he is trying to sell.

                  I have no issues with someone providing information or a place to look at specific hardware but I believe anyone that posts hardware that they sell should first get approval of the Solar Panel Talk forum owners.
                  Iron Bran is hardly a first time user.

                  Comment


                  • Originally posted by discovery5 View Post
                    Iron Bran is hardly a first time user.
                    Maybe not but he shouldn't have been selling his hardware or providing pictures of his hardware for people to see and maybe go purchase.

                    We have discussed numerous types of batteries and PV hardware on this site. Most provide good data but are not trying to actually sell anything. Although there is a "line" that some posters cross.

                    I was just pointing out that I felt Iron Bran was using this thread to advertise his hardware which may have been ok with the Moderators or maybe not.

                    Comment


                    • Originally posted by SunEagle View Post
                      Maybe not but he shouldn't have been selling his hardware or providing pictures of his hardware for people to see and maybe go purchase.

                      We have discussed numerous types of batteries and PV hardware on this site. Most provide good data but are not trying to actually sell anything. Although there is a "line" that some posters cross.

                      I was just pointing out that I felt Iron Bran was using this thread to advertise his hardware which may have been ok with the Moderators or maybe not.
                      Not as far as I am concerned - if he wants to sign up with Solar Pete for paid advertising then fine - until then there is no reason we should allow an advertising of an different system. We have no idea what is being sold, the quality or any thing else about it.
                      [SIGPIC][/SIGPIC]

                      Comment


                      • So, do any of you have photos to share?

                        Lots of chatter, very few photos. Anyone have actual install photos to share???

                        Originally posted by russ View Post
                        Not as far as I am concerned - if he wants to sign up with Solar Pete for paid advertising then fine - until then there is no reason we should allow an advertising of an different system. We have no idea what is being sold, the quality or any thing else about it.

                        Comment


                        • Originally posted by discovery5 View Post
                          Interested in this thread for LiFePO4 for replacement of Lead Acid Battery Bank and would like to see the pictures.
                          here is the floor plan layout for my battery shed. I replaced a 600ah Pb-H2So4 bank, with an 800ah NiFe bank. Took a lot more floor space, and if I'd not had it in mind beforehand, it would not fit.
                          BatteryShedLayout_2_NiFe2.jpg
                          More photos in my .sig links
                          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


                          • Originally posted by Iron Bran View Post
                            Lots of chatter, very few photos. Anyone have actual install photos to share???
                            You are asking this as a lead in so you can post about what you are trying to sell?
                            [SIGPIC][/SIGPIC]

                            Comment


                            • A Picture is worth a thousand words

                              Originally posted by Mike90250 View Post
                              here is the floor plan layout for my battery shed. I replaced a 600ah Pb-H2So4 bank, with an 800ah NiFe bank. Took a lot more floor space, and if I'd not had it in mind beforehand, it would not fit.
                              [ATTACH=CONFIG]6415[/ATTACH]
                              More photos in my .sig links
                              Thanks for the Pics

                              Comment


                              • Originally posted by Iron Bran View Post
                                Lots of chatter, very few photos. Anyone have actual install photos to share???
                                Most people don't want the criticism and ridicule from the posters that inhabit the site. Potential Advertisers / Sponsors would see it as a net loss to be on here.

                                Comment

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