Schneider XW+6848 and MPPT 80 600 settings questions

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  • Hotrod
    Junior Member
    • May 2019
    • 27
    #1

    Schneider XW+6848 and MPPT 80 600 settings questions

    Hello all. So, I'm running 2-XW+6848s with 2-MPPT 80 600 CCs, a combox, 13.4kW array, and a 1430AH FLA battery.

    The battery is a refurbished 24-85-27 GNB battery and the seller told me the voltage settings are:
    Bulk= 59.4
    Absorb= 58.2
    Float= 54.0
    EQ= 63.0

    So i changed the settings in the 6848 and they took just fine. I cant change those settings in the CCs. So it sticks to the factory settings of:
    Bulk= 57.6
    Absorb= 57.6
    Float= 54.0
    EQ=64.0

    It's using the settings in the CCs and not the 6848s. Why cant I change those settings? Why doesn" the Master inverter dictate charge voltages and profiles to the CCs? Am I missing something?

    Another question is why won't the system drive to full out put when the grid support voltage is set above the EQ voltage as suggested in the manual. When I follow those instructions the system does exactly what it says it will but clips the solar output to ~5kW once the battery is in float. If I drop the grid support voltage to 49.5 during a bright sunny day with the battery in float I've had it hold ~9kW for several hours. ~8kW is what i expected the equipment to produce at full tilt, so when i managed to get a little over 9kW i was pleasantly surprised. Why does it clip the array to ~5kW? the attached screenshot shows the difference of changing nothing but the grid supply voltage from 65v to 49.5v with direct light, although not at apex, notice time of day. After 2 minutes I changed it back. Clouds are spotty today and if the GSV is at 49.5 when a cloud passes over it sells power to the grid from the battery. I want it to never use from the battery while generating power regardless of GSV setting. I want it to run the battery through a complete charge cycle without interruption once it starts, no matter the solar output. Make the battery the priority during daylight hours and run from the grid or solar during that time. I'd like to tie the battery directly to solar output so that as long as there is output from the solar array, the battery is charged, using the grid if necessary, to maintain a perfect charge profile and maintain it in float until the array drops below cutoff voltage for the CCs. Are there settings to do that?

    Screenshot 2019-05-28 at 11.06.16 AM.png

    Jason
    Last edited by Hotrod; 05-28-2019, 12:41 PM.
    Too much stuff for 50 characters
    Tags: None
    • extrafu
      Solar Fanatic
      • Apr 2016
      • 185
      #2
      I have the same gear but also with a generator. The settings in the XW6848 are for when the generator is used, the settings from the CCs are for when solar panels are used. That's why they are different. You can change them from the SCP by entering in advanced mode or from the Combox. Also make sure you adjust your battery bank capacity vs. 2% Ah cut-off from absorb to float based on your battery specs. The 2% is hardcoded on the CCs, you can't change that so if you want to switch from float to absorb when you reach 1% Ah of your rated battery capacity, you must set the battery bank to 50% of its true size. I learned that the hard way last year and it sulfated my Rolls batteries a bit.

        Comment

        • DickyDck
          Member
          • Sep 2018
          • 57
          #3
          interesting, I see the same/similar results when adjusting the Grid Support voltage around... wonder why this is...

            Comment

            • paulcheung
              Solar Fanatic
              • Jul 2013
              • 965
              #4
              To the OP, Do you have Net Metering? if you do. you shouldn't cycle the batteries unless for periodically exercise the battery bank. if you have Net Metering, set the grid support voltage at 54 like the floating volts. your battery will keep full all the time except when you exercise them or when you have a power cut and no sun.

                Comment

                • DickyDck
                  Member
                  • Sep 2018
                  • 57
                  #5
                  Originally posted by paulcheung
                  To the OP, Do you have Net Metering? if you do. you shouldn't cycle the batteries unless for periodically exercise the battery bank. if you have Net Metering, set the grid support voltage at 54 like the floating volts. your battery will keep full all the time except when you exercise them or when you have a power cut and no sun.
                  Could you define "exercise" please, I'm relatively new in the solar thing and don't know all the terminology yet. My batteries are AGM so if "exercise" means the same as "equalize" then it doesn't apply to me and my setup.

                    Comment

                    • SunEagle
                      Super Moderator
                      • Oct 2012
                      • 15126
                      #6
                      Originally posted by DickyDck

                      Could you define "exercise" please, I'm relatively new in the solar thing and don't know all the terminology yet. My batteries are AGM so if "exercise" means the same as "equalize" then it doesn't apply to me and my setup.
                      My definition of "exercise" would be to "use" more cycles on the batteries. A higher cycle rate will lower the lifespan of all batteries.

                      So the question is saving the few pennies when you use the batteries worth the cost of a new set sooner then expected?

                        Comment

                        • paulcheung
                          Solar Fanatic
                          • Jul 2013
                          • 965
                          #7
                          Originally posted by DickyDck

                          Could you define "exercise" please, I'm relatively new in the solar thing and don't know all the terminology yet. My batteries are AGM so if "exercise" means the same as "equalize" then it doesn't apply to me and my setup.
                          I was assume the batteries are FLA. since they are AGM then you won't have any problem. just use them as stand by and set the grid support voltage to 54 volts and you batteries will last as long as they are design for.

                            Comment

                            • Mike90250
                              Moderator
                              • May 2009
                              • 16020
                              #8
                              How deeply do you want to exercise the batteries (use them up) ( Exercise is not the same as Equalize )

                              Each cycle of a battery wears it out somewhat. Do you consume a $3,000 battery in 2 years in order to shave $40 monthly on the electric bill ? If you only shave $3 monthly, you get 8 years life from your battery.

                              The following chart shows the deeper the cycles (exercise) the shorter the battery life (this is a generic chart, the one for your battery will basically be the same)

                              DoD_vs_CycleLife.gif
                              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

                                • DickyDck
                                  Member
                                  • Sep 2018
                                  • 57
                                  #9
                                  Originally posted by SunEagle

                                  My definition of "exercise" would be to "use" more cycles on the batteries. A higher cycle rate will lower the lifespan of all batteries.

                                  So the question is saving the few pennies when you use the batteries worth the cost of a new set sooner then expected?
                                  I think in my setup, the batteries are constantly in an influx of in/out since I have a XW6848 which is grid-tie only? So I think the batteries are always doing a low "exercise"

                                    Comment

                                    • paulcheung
                                      Solar Fanatic
                                      • Jul 2013
                                      • 965
                                      #10
                                      4000-IEC-1024x574.jpg Mike This is a chart from Roll 4000 series RE batteries. it is a little different from the one you have above, and the one below is Rolls 5000 series. Your chart from a regular deep cycle battery?5000CYCLEDOD-e1556766144472-1024x761.png
                                      Last edited by paulcheung; 07-30-2019, 11:04 AM.

                                        Comment

                                        • paulcheung
                                          Solar Fanatic
                                          • Jul 2013
                                          • 965
                                          #11
                                          Originally posted by DickyDck

                                          I think in my setup, the batteries are constantly in an influx of in/out since I have a XW6848 which is grid-tie only? So I think the batteries are always doing a low "exercise"
                                          Since you have AGM this won't apply to you. With FLA batteries. We have to use the batteries periodically to stir up the electrolytes so it won't settle in the bottom. Once per week I cycle my bank to 40 to 50%DOD and charge back with C/8 current. That is what I mean exercise the battery bank.

                                            Comment

                                            • SunEagle
                                              Super Moderator
                                              • Oct 2012
                                              • 15126
                                              #12
                                              Originally posted by DickyDck

                                              I think in my setup, the batteries are constantly in an influx of in/out since I have a XW6848 which is grid-tie only? So I think the batteries are always doing a low "exercise"
                                              A "slow" exersize could cause an early death to some batteries. In other words "they need to be kicked in the butt" every once and a while to truly exercise them but not every day. Also a daily low "exercise" may cause the battery to stagnate and never allow it to get back to 100% SOC.

                                                Comment

                                                • DickyDck
                                                  Member
                                                  • Sep 2018
                                                  • 57
                                                  #13
                                                  Originally posted by SunEagle

                                                  A "slow" exersize could cause an early death to some batteries. In other words "they need to be kicked in the butt" every once and a while to truly exercise them but not every day. Also a daily low "exercise" may cause the battery to stagnate and never allow it to get back to 100% SOC.
                                                  Even for AGMs? It is set to bulk recharge daily, but if that is too much I shall modify.

                                                    Comment

                                                    • SunEagle
                                                      Super Moderator
                                                      • Oct 2012
                                                      • 15126
                                                      #14
                                                      Originally posted by DickyDck

                                                      Even for AGMs? It is set to bulk recharge daily, but if that is too much I shall modify.
                                                      All battery chemistries are slightly different. Some allow deeper discharges or higher recharges. The trick is to find what is needed to get the most cycles at whatever is the best DOD% for your batteries.

                                                      There should be some type of direction to recharge your AGM's but again the battery people are in the business to sell you new batteries so I would investigate more on the battery manufacturer feedback forums.

                                                        Comment

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