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Bobster

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Bobster last won the day on December 31 2021

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  1. It's a good idea, thanks, but I don't think it will do much good. There are 4 LEDs, so 25%, 50% and so on. When it's DISCHARGING and you see 3 LEDs you know it's somewhere north of 50%. When it's charging, you will get one flashing light, that's the "segment" that's charging now. So two LEDs on and a third flashing tells you that it's past 50%, not yet at 75%. So the chances of catching it at exactly the right moment would be slim. But back to my original question - 2 years ago my batteries could power that heat pump in the morning. Now the batteries last about 20 minutes doing the same job. I know that the batteries will degrade over time, but is this exceptional degradation or not? If not then I just have to learn to live with this increasing decline in performance. BTW, all the firmware involved is not much help here. Ever since I've been paying attention (at least a year), the "state of health" for the batteries has been reported as 103%. Huh?
  2. I called Revov. They told me how to check if the batteries are 100% and if there is cell balancing going on. However this involves watching LEDs on the the BMS - who has the time? But I am grateful for the information.
  3. A recurring event in my solar life. Remembering that the green trace is SOC, look what happened later today (this is not uncommon)
  4. Here's an illustration. I don't know if this is usual/acceptable or not. But I believe that numbers don't lie, so this is what it is. With a return to the office and thus an early morning commute imminent, I want to run my heat pump earlier in the morning. I used to do this. It was the situation when my system was installed in mid 2019. Here's what happened 23rd July 2019 SOC at midnight was 82%. Pump turns on at 4:30 with SOC 75%. The thermostat turns the pump off at 6:10 with SOC now 41%. Here's what the portal shows me for 25th Jan 2020 70% SOC at midnight. Heat pump kicks in at 4:30. SOC when the heat pump turns on is 58%. At 5:15 the thermostat kicks in, heatpump turns off and SOC is 46% at that point. Whilst I've been working from home I have set the heat pump to turn on later as I take exercise in the morning and don't have to leave early to get the bus. Now with a return to the office looming I want to start running it early again. So this is what happened this morning. SOC at midnight was 76%. Heat pump turns on 5:30 with SOC at 60%. 25 minutes later SOC has hit 40% (my maximum on-grid DOD is 60%) and the system starts drawing from grid. Load in 2020 and 2022 varies around the 1.8 kw mark. So these batteries seem to have lost quite a bit of woema in 2 years.
  5. I think there is an element of truth to this. Eskom and City Of Johannesburg, where I live, have both been arguing for a split fee for all properties connected to the grid. One part of this will be fixed and will pay for the connection, the other is for actual consumption. At the moment post-paid residential single phase users in COJ pay about R700 a month in flat fees. Prepaid users pay a higher per kw/h rate, but not flat fees, so if you are careful with using electricity then you can save quite a bit (still, though not as much as you could 5 years ago). The cost to the city of supplying a post and prepaid property is the same, but not everybody is paying equally towards the provision.
  6. I'm wondering if it's financially viable anywhere. I live in Jhb and I could export some power most days, but I'd have to change to the reseller's tariff, which means about R700 a month in flat fees, plus I'd have to pay over a grand for the required meter. At the rate they buy back at, I'd have to export a lot to effect an actual saving, so it's cheaper for me to just not export.
  7. Sure. But if it goes from 999956 to 000002 then that's no real problem. But do the same calculation using the figures that I provided and you will get a nasty surprise when you bill comes through the letter box.
  8. Some tings seem to be a matter of interpretation. After some work about a year ago I chatted with the electrician about a COC. He said sure. I said "what about the solar system? are you comfortable with that?". He said "oh we can just put that down as an 'appliance'".
  9. It is the case that there is an extra level of complexity with pre-paid meters. Makes sense, they have to track consumption AND credit. I always wonder when I hear these stories about meters running backwards. I think it's OK if you are still a net consumer, but imagine this situation Opening reading 123456 Closing reading 123433 Any half way decent billing system would be built to cope with a scenario where a meter will eventually get to 999999 and then to 000000. What would such a system do with such figures?
  10. I do this, but for me it introduces a danger period. My heat pump kicks in at 7am. If there is solar by then, then all well and good, but on overcast mornings like this morning my battery very quickly hits the allowed DOD and I start drawing from the grid. If there is an outage then - with my inverter - I need to either turn off the geyser, or take a chance on allowing the battery to be depleted. It would probably last an hour. There are never perfect solutions, but maybe you can plan a little differently here and change the run time for the inverter (or maybe the Sunsynk is smarter than the Goodwe). The worst case scenario now is bad weather and load shedding. When I know we have load shedding I pay more attention to weather forecasts and I look at the load-shedding schedule and may decide to top my battery up a bit round about 4am if we are going to have early morning shedding and it looks like the sun will not be shining too brightly.
  11. And he answered truthfully but incompletely. In any municipality where feeding back is allowed, you must at least have a special two way meter, configured to allow the feedback. Also, in most cases it is not worth your while. Tshwane allow it, sure, but it will probably mean the aforementioned meter, probably at your cost, and a change to a reseller's tariff. Check the tariffs. COJ allow reselling but it simply isn't worth it for most homeowners (if you have business premises with lots of space for panels then maybe) so I set my system to not export. However it exports a little every day. I presume this is to try to reset the usual small movement on the meter, but it doesn't work - which may again be down to the meter. But we are talking a few rand a month here, and the cure, for me, is to go on to the reseller's package which will mean about R700 a month in flat fees, a new meter at my expense, and a buy back tariff of... I can't remember, but a good distance south of R1 per kw/h exported. So I take that small loss every month. Summary 1) Get a copy of the tariffs and do the sums and see if there is a net benefit to you reselling. 2) In the meantime set your inverter to not export.
  12. It's long seemed to me that both the app and the portal infer some figures rather than use data from the system.
  13. Possible. But I have a different kind of battery and a different kind of BMS. And the manufacturer of the batteries is advertising that they can be discharged all the way with no harm. I'm not saying the latter claim is true, but why would they then put a hard limit into their BMS?
  14. I have firmware 2121D and a different brand of battery. I can't set the DOD lower than 90%. So I suspect this is a hard limit in the app or in the inverter.
  15. Thanks. Just in case I ever have to tell an electrician to look out for it.
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