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Discrepancy between Rolls/Surrette S-550 and Battery Bank spec sheet/description

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  • Discrepancy between Rolls/Surrette S-550 and Battery Bank spec sheet/description

    I was looking at an ad on a website for a 24V 428Ah bank: http://www.wholesalesolar.com/189852...vdc-10272-wh-4

    And the individual 6v 428Ah batteries I assumed are in the bank: http://www.wholesalesolar.com/990015...batteries/s550

    The battery bank description refers to 3000+ cycles at 50% DOD and 2000+ cycles at 80% DOD, and the S-550 battery spec sheet has a chart that shows approximately 1500 cycles at 50% DOD and 750 cycles at 80% DOD.

    I tried calling the reseller, and they said they are going to have someone get back to me. Anyone here have a comment on this apparent discrepancy? My eyes lit up when I saw #'s like 2000 and 3000 cycles... I am missing something.

    Thanks in advance.

  • #2
    Originally posted by Living Large View Post
    The battery bank description refers to 3000+ cycles at 50% DOD and 2000+ cycles at 80% DOD, and the S-550 battery spec sheet has a chart that shows approximately 1500 cycles at 50% DOD and 750 cycles at 80% DOD.

    I tried calling the reseller, and they said they are going to have someone get back to me. Anyone here have a comment on this apparent discrepancy? My eyes lit up when I saw #'s like 2000 and 3000 cycles... I am missing something.

    Thanks in advance.
    Reseller never called me back. I have verified that the bank is made up of four S-550 cells. It can't be that the individual batteries are spec'd at 1500 cycles at 50% DOD, and a bank of 4S is 3000+ cycles at 50% DOD. Sloppy advertising?

    Comment


    • #3
      maybe they mean if you buy 8 of em and switch them out every other day?
      1150W, Midnite Classic 200, Cotek PSW, 8 T-605s

      Comment


      • #4
        Originally posted by Living Large View Post
        I was looking at an ad on a website for a 24V 428Ah bank: http://www.wholesalesolar.com/189852...vdc-10272-wh-4

        And the individual 6v 428Ah batteries I assumed are in the bank: http://www.wholesalesolar.com/990015...batteries/s550

        The battery bank description refers to 3000+ cycles at 50% DOD and 2000+ cycles at 80% DOD, and the S-550 battery spec sheet has a chart that shows approximately 1500 cycles at 50% DOD and 750 cycles at 80% DOD.

        I tried calling the reseller, and they said they are going to have someone get back to me. Anyone here have a comment on this apparent discrepancy? My eyes lit up when I saw #'s like 2000 and 3000 cycles... I am missing something.

        Thanks in advance.
        I couldn't respond yesterday but I think there is some misleading information between the two systems.

        The 24VDC battery bank (4 x 6v) does indicate 2000+ cycles at 80% DOD which I believe really means 80% SOC. So where the S-550 specs indicates that you get 750 cycles at 80% DOD you can see that it also shows 2000+ cycles at 20% DOD or (80% SOC). So that can be confusing.

        Now I have no clue as to why the 50% DOD cycle numbers are twice as much (3000+) for the "bank" then the single S-550 battery at 1500+.

        Again it might be a typo because both adds are referring to the same S-550 battery.

        Comment


        • #5
          Originally posted by thastinger View Post
          maybe they mean if you buy 8 of em and switch them out every other day?
          Maybe. That ad for the bank appears to me a copy-paste conglomeration of item-specific S-550 and general information on Rolls-Surrette. If they said "up to" 3000+ cycles, I would feel better. As it stands, I'm pretty uncomfortable with that item description.

          The fact that none of the "technicians" the website advertises has gotten back to me concerns me also.

          Comment


          • #6
            The Rolls S-550is a Rolls 4000 series batteries. My point is do not go by what a distributor says just pull the sec sheet. If you are going to consider a L-16 battery which is what the Rolls S-550 really is, also look into a Trojan Industrial line of batteries. They cost less and every test ran indicate these of a solid 7 year battery.
            MSEE, PE

            Comment


            • #7
              Originally posted by Sunking View Post
              The Rolls S-550is a Rolls 4000 series batteries. My point is do not go by what a distributor says just pull the sec sheet. If you are going to consider a L-16 battery which is what the Rolls S-550 really is, also look into a Trojan Industrial line of batteries. They cost less and every test ran indicate these of a solid 7 year battery.
              Thanks. The distributor in this case also tauts an average life expectancy of 10 to 15 years. My inclination was to go by the spec sheet, which shows a cycle life a fraction of what they are showing in their description. Live and learn. As a newbie, I thought the distributor's #'s were too good to be true - though I know this is a very good battery.

              I was considering a downsized (1/4 of what I had planned) system to hold me over for 3 to 5 years, and then get rid of solar altogether when neighbors nearby are available to help make POCO a more economical option when they catch up from the economic downturn and build. I would need to go to 60% or 70% DOD - 1000 cycles. I suppose I may make that, depending on definition of cycle - and if it is 1000 or 2000 cycles, it wouldn't really matter. But I still have the 6 to 8 hour gen run time I was trying to escape by going LFP. Still crunching #'s.

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              • #8
                LL check this site out. Sorry for no embedded link, site does not seem to be working right. I get no editing tools.http://www.mpoweruk.com/life.htm
                MSEE, PE

                Comment


                • #9
                  Originally posted by Living Large View Post
                  Thanks. The distributor in this case also tauts an average life expectancy of 10 to 15 years. My inclination was to go by the spec sheet, which shows a cycle life a fraction of what they are showing in their description. Live and learn. As a newbie, I thought the distributor's #'s were too good to be true - though I know this is a very good battery.

                  I was considering a downsized (1/4 of what I had planned) system to hold me over for 3 to 5 years, and then get rid of solar altogether when neighbors nearby are available to help make POCO a more economical option when they catch up from the economic downturn and build. I would need to go to 60% or 70% DOD - 1000 cycles. I suppose I may make that, depending on definition of cycle - and if it is 1000 or 2000 cycles, it wouldn't really matter. But I still have the 6 to 8 hour gen run time I was trying to escape by going LFP. Still crunching #'s.
                  Could you salvage most of your hardware and convert to grid-tied when POCO is available?

                  Comment


                  • #10
                    Originally posted by Sunking View Post
                    LL check this site out. Sorry for no embedded link, site does not seem to be working right. I get no editing tools.http://www.mpoweruk.com/life.htm
                    Thanks Dereck. I got about 1/4 the way through tonight, and it's getting deeper. I'll go back for more. Good stuff!

                    Comment


                    • #11
                      Originally posted by lkruper View Post
                      Could you salvage most of your hardware and convert to grid-tied when POCO is available?
                      Maybe. Low insolation in my area, and shading after 2:30pm. I don't think I can get any assistance with installation costs either initially, or after POCO, and I don't know how much I would be able to transfer over. Something to keep in mind I guess. Also, I'm thinking 1/4 my long term energy budget - so I would probably have to expand the system after going POCO.

                      Comment


                      • #12
                        Originally posted by Living Large View Post
                        Maybe. Low insolation in my area, and shading after 2:30pm. I don't think I can get any assistance with installation costs either initially, or after POCO, and I don't know how much I would be able to transfer over. Something to keep in mind I guess. Also, I'm thinking 1/4 my long term energy budget - so I would probably have to expand the system after going POCO.
                        Bummer on the shading. However if you are good from AM till then, you probably do get 50%+ of your power between 10AM and 2PM. One thing that surprised me is how big a difference panel orientation affected insolation. Are you planning on roof mounted panels? If you could pole mount them and change the orientation by season you might be surprised how much more power you get, especially in winter.

                        I don't understand why you would expand the system after POCO since you will have cheap power. If you could continue to use them as backup that would be a plus and if you could get net metering you would get some of your investment back.

                        Comment


                        • #13
                          Originally posted by lkruper View Post
                          Bummer on the shading. However if you are good from AM till then, you probably do get 50%+ of your power between 10AM and 2PM. One thing that surprised me is how big a difference panel orientation affected insolation. Are you planning on roof mounted panels? If you could pole mount them and change the orientation by season you might be surprised how much more power you get, especially in winter.

                          I don't understand why you would expand the system after POCO since you will have cheap power. If you could continue to use them as backup that would be a plus and if you could get net metering you would get some of your investment back.
                          I was planning for a fixed mount on a custom roof, due south favored towards optimum winter angle. I don't have much excess real estate available.

                          I haven't put much thought into "net metering" since I have been doing all I can just to get approval to spend big $$$ to install POCO. The thought just occurred to me to do something temporary with solar, and switch over in a few years - driven by neighbors not ready to build today but maybe in a year or two, that would result in $30,000+ in free primary wire length. Yes, that is risky to rely on - but I need to explore all options. I would only have 4 panels with this reduced capacity, which I guess I assumed would not warrant net metering.

                          Comment


                          • #14
                            Originally posted by Living Large View Post
                            I was planning for a fixed mount on a custom roof, due south favored towards optimum winter angle. I don't have much excess real estate available.

                            I haven't put much thought into "net metering" since I have been doing all I can just to get approval to spend big $$$ to install POCO. The thought just occurred to me to do something temporary with solar, and switch over in a few years - driven by neighbors not ready to build today but maybe in a year or two, that would result in $30,000+ in free primary wire length. Yes, that is risky to rely on - but I need to explore all options. I would only have 4 panels with this reduced capacity, which I guess I assumed would not warrant net metering.
                            You are designing a custom house?

                            Comment


                            • #15
                              Originally posted by lkruper View Post
                              You are designing a custom house?
                              At one point, I was thinking about designing into the side of the house. No, this would be a detached garage, which I need anyway.

                              Comment

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