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admin
When charging 50% it charges with 5.02 kW.

5 kW is 50% of 10 kW, so inverter uses its max rate for percentage calculation.

I might have misunderstand how the calculation in WW works and why numbers come out as they do. What I want is that the calculated charge is distributed over the available periode. With upper numbers as example):
Battery capacity times (1 - SOC) divided by hours in period.
12.8 * (1-55/100) / 6 = 0.96 kW. Which is 9.6% of the 10kW. However, WW have calculated todays charge rate to 18%, which means, that charge has finished in 3.2 hours. I expected the charge to be distributed over all 6 hours. How can I achieve this?

      Status last night :
      Charge stop SOC 95%
      Charge rate 100%

      Status this morning::
      charge stop SOC : 100%
      charge rate at 100%

      I had put the battery max setting to 3kW , to give it a try.

      Looking at my import graph it seems charge at full 100% for about 30 min, but stop at the correct target level (it just hit SOC 74%)



      So SOC stop setting seems to work, but not charging rate

      So just to confirm: 50% charge rate is 50% of inverter power. I do not know if inverter may limit this by battery max rate for smaller batteries, not sure how I could check that .

      Note , at the end of the charge session can you set back the charge stop SOC and charge rate to what is was before the charge session ? Say WW charges it with 30% , in the afternoon I need it back to say 100 charge rate and my 95% default stop SOC to maximally charge via solar - ( I prefer 95% think better for batteries, but guess WW setting it back to what it was is always best option ?)

      Thanks

      perfrank

      5 kW is 50% of 10 kW, so inverter uses its max rate for percentage calculation.

      Cool, so now we know that, we also need the inverter max charge, as well as your battery max charge of 5-6kW.

      We'll add a setting for that (which we assumed we may have needed, so just as well we kept this under the Advanced section!).

      We basically need both (if they are different) in order to calculate the correct charge rate. If inverter charge rate isn't being set by the user, we just use the max charge rate of the battery.

          ok, I have notices something odd today...
          I have changed no advanced settings as far as I am aware (I did view them), and overnight charging correctly grid charging to 100%, but today the solar has pretty much stalled at 80%-ish and is exporting the majority.
          I cannot be sure if this is some oddity inside Growatt or the inverter, or if WW has set something...

          I know WW writes out to Time Slot 3, so not sure if the grid first is causing this?

            krustydad Ah, it might because with TL-X inverters you need a specific window/timeslot for Load First that should be enabled? @Jorrit ?

                admin It's been working fine until today, so not sure.

                UPDATE: it seems that Charge Stop SOC (seen above as 20%) was set by something.
                I have not knowingly changed this, but setting to 100% the battery has immediately started to charge from solar again.
                I cannot see anything in the WW log that makes me think this has been set, but is there anything not visible in the UI that could explain WW setting this?

                If it helps, I had looked at the Agile Octopus configuration page, and entered my postcode "to see what happened" but didn't save any changes as far as I know.

                    krustydad

                    So the question then is, did you Change Timeslot 3 back to Load First and also left it at disabled? And did that fix it?

                        Default is load first, so that would not need any timeslot. I think the thing we noted was in the timeslot you can only set the ‘mode’, nothing else . All other settings are general , ie apply all the time (and for all timeslots.)

                        Again , just to confirm I see the same on the server page : Timeslot 3 is left after WW charge with “grid first” with timesetting 00:00 - 00:01 and disabled .

                        (Guess you need to do like that as it seems you can not save back to default 00:00-00:00 . Will not accept that . So very messy time set up in Growatt it seems to me )

                        krustydad

                        UPDATE: it seems that Charge Stop SOC (seen above as 20%) was set by something.
                        I have not knowingly changed this, but setting to 100% the battery has immediately started to charge from solar again.

                        We do set both charge rate and charge SOC back to 100 at the end of the charge schedule. Those values are actually hardcoded at the moment.

                        From the logs I also couldn't spot anything to the contrary for your account. Charge rate and charge SOC stop got reset successfully.

                            krustydad
                            From Your screenshots I can see, that Your HX model is different from my SPH in the settings. On SPH, priority is set by enabling time slots in either "Grid first" or "Batteri first" group. Obvious not both can have an active timeslot. If neither is active at the actual time, SPH defaults to "Load first". I assume, that if all timeslot is "Disable", Your inverter should preferably do the same: Default to "Load first". If it does not, things get a little more complicated, and WW (or You) should set an enabled "Load first" slot.
                            I hope, that this makes sense. English is not my native language, and I struggle to make myself clear. And i miss a dictionary, with definitions, over PV related terms. Growatt could use that too;-)



                              admin Sounds fine.
                              When you get the time, I will very much like to have a description of the logic behind the Scheduled time slots with the calculation rules. Or is it very complicated? Or secret? It is just because I can better decisions entering parameters when I know the logic behind.

                                admin OK , checked it in a trial schedule. The schedules say charge to 37% with charge rate 43% . These settings are both correctly visible on the server and the time slot (3) is correctly set to grid first. We have already seen it will re-set back to 100% for SOC stop and charge rate after the session, so the integration works correctly

                                I also see it charging with 4.1 kW which seems in line with the 43% (9kW inverter)

                                  But for the calculation, I think there are some issues there:

                                  the schedule calculated a 43% charge rate (= approx. 4,1 kW in my case) with the max battery rate set to 3 kW in advanced setting (Smart battery charge enabled)

                                  And it calculated a charge rate of 43% to go from SOC 35% to target SOC 37% (2% increase which is 0,6 kWh in my case) for the set time period of 30 minutes .

                                  (In my logic is should have charged with 1.2 kW to reach the target in the 30min slot ., so 1.2kW /9kW * 100% = 13% charge rate

                                  With the calculation putting a max for the battery charge rate setting. In my case I put 3kW as battery max charge =33% max charge rate )

                                  You want to share your calculation logic or do you want it to work different as I describe perhaps? ( and “ Krustydad” I believe)

                                    Jorrit We'll put a fix out tomorrow for this and I'll post the way we calculate the charge rate.

                                        admin As you guessed, I did edit Slot 3 to Load First (sorry I didnt mention this previously - I forgot - I have started to log manual config changes so I can report correctly and also undo anything detrimental) but this had no effect despite waiting an hour or so. Only changing Charge Stop SOC allowed charging to continue as expected.

                                        Thanks for your continuing support and responsiveness

                                          admin Looking forward to see the logic.
                                          And I recognize, that You have a hard job developing WW. Managing different inverters from several suppliers in different versions and properly some obscure API which are not well documented. It can't be easy. And I see Your point in keeping general settings clean with minimum parameters. Let's hope "Advanced" menu can be held with a few settings.

                                          Could a drop down menu with different (supported) inverters be a way to manage things in the UI? In the background You could maintain differences in behavior and calculate accordingly? In the long run, I thing this will keep things tidy and improve oversight.

                                          I see, that the drop-down is already there. Maybe expand it with different types SPH, HX, etc.

                                              perfrank

                                              Looking forward to see the logic.

                                              So - to calculate the charge rate, given we know how many target kWh we need, the time window to charge in, and the max battery plus max inverter charge rates:

                                              var chargeRatePercentage = (targetKWattHoursRequired / offPeakWindowInHours) / maxBatteryChargeRate * 100;
chargeRatePercentage = (maxBatteryChargeRate/inverterMaxChargeRate)*chargeRatePercentage;

                                              For most people the adjustment on the second line is simply a multiplication of 1. In your scenario, it will be the 6/10 adjustment to recalculate the percentage based on your inverter max charge being higher than your battery max charge rate.

                                              Ran it with a few unit tests and test cases, looks good and would work for you.

                                              The only other thing we add is if the charge rate is below 10%, we set it to a lower bound of 10%. Not sure there's much point getting calculated values like 1 and 2 % charge rate...

                                              Let me know what you think, we'll probably roll this out later on today.

                                                  admin hi Admin . But I think this may not be correct . I do not think you should make the battery charge rate part of the calculation at all. I believe it should only function as a max rate.

                                                  You calculate as you say the percentage based on required charge rate and the time slot . You just want to max out out on the battery rate.

                                                  chargeRate= MINIMUM ( (targetKWattHoursRequired / offPeakWindowInHours ; MaxBatterychargerate)

                                                  ChargeRatePercentage= Minimum( charge rate / maxinvertchargerate *100% ; 100%)

                                                  (also assuring calculation never exceeds 100%)

                                                  ( formula in Excel style)

                                                  Or in other words , as long as you do not exceed the battery charge rate you do no want to charge any slower , the target is still the target.

                                                  Does that make sense to you ?
                                                  Thanks

                                                      Jorrit

                                                      Looks to me like we are using a similar mechanism and all the same inputs.

                                                      You mentioned earlier that when you send 50% charge rate to your inverter, your battery charges at 5kW.

                                                      If we just use your battery max charge rate of 6kW, as you suggest, and we work out you need 3kWh in one hour charge window, and plug those values into our formula, we end up with the 30% value too.

                                                      Just give it a test run. 😄

                                                        Reason for me raising the case was two fold:
                                                        1) On my system (10kW inverter, 12.8kWh battery), it looked a little strange that 50% charge rate gave 5Kw charge power and 100% charge rate gave 6kW charge power, due to the limited charge power allowed by the battery. But this is not that essential, just a strange charge curve;-)

                                                        2) WW charged with a higher power that necessary, thereby nor utilizing the whole charge period.

                                                        I believe, that "Low and slow" is best for batteries (along with not utilizing extremes like 0% or 100% for longer periods. And I thought, that WW could be optimized with respect to battery life by taking into account the maximum charge rate possible for a given battery. This said, I have not found any scientific sources with relevant information regarding this.

                                                        By the way, I found out, that Growatt limit discharge to 10%. It is not user kontrollabel and they will not guarantee battery life if changed. So, I paid for 12.8 kWh and got 11.5kWh.

                                                        Thank You, Admin, for taking the time to improve WW on this topic, I'll try it out a few days and report back with the results.