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Everything posted by Bobster

  1. PS. So far today (it's 18:10 now) I've drawn 0.74 kw/h from the grid.
  2. Thanks @Coulomb. That's a more plausible explanation. Exporting is a matter of where one lives. In CT it is allowed and people do it. In Johannesburg (where I live) it is allowed but the tariffs make it not worth my while. So they allow it and discourage it at the same time. Starting with the special meter that I have to pay for.
  3. Thanks @Coulomb. That's a more plausible explanation. Exporting is a matter of where one lives. In CT it is allowed and people do it. In Johannesburg (where I live) it is allowed but the tariffs make it not worth my while. So they allow it and discourage it at the same time. Starting with the special meter that I have to pay for.
  4. I've mentioned this before. I get a puzzling situation on my system where reported SOC makes a sudden jump. This happened today Now this has been worrying me. It's happened quote a lot lately. The jump always happens when 1) SOC drops to 40% or lower 2) When reported SOC rises back to 70ish %. So what do I believe? The 70 or the 100? I mailed Revov. They sent somebody out to test the batteries. This pleased me - I have some support. The technician checked ONLY the batteries. This seemed fair to me. The rest of the system is not theirs. Some points that emerged from this 1) The Revovs are "1C" batteries. As I understand it, this means they can be charged quickly, and they supply quite a hefty current on discharge. 2) The charge current on my system is set to 90.23 amps. Which (tech says) is high but OK for the batteries I have. 3) The tech interrogated the Revov BMS to check the condition of each cell in the battery pack and to look for error logs. This test gives the battery pack a clean bill of health. He says I should believe the 100 4) He also hypothesised that if the charge current was reduced then the sudden jump would be less sudden. 5) Between the BMS and the Inverter there is another box, added by my installer to stabilise the system. This is not made nor supplied by Revov. So what the portal is getting is the output from that box. This seems to me to be a major problem with these systems, because no company makes entire systems. You always get batteries from one company, panels from a second, batteries from a third. In my case a BMU from a 4th. So the challenge is to get all the bits working together harmoniously, and quite naturally the various manufacturers will only offer support and be concerned about their part of the system. In this case it didn't lead to fingerpointing, but I can see how it could have. 6) He tells me business is very good right now. Lots of people are installing solar at home or at business. But nice that they sent somebody out to run some diagnostics on a 2 year old battery pack.
  5. This. My hybrid system uses a small amount of grid power on even the sunniest of days. When you think about it, this makes sense. These inverters have the ability to send spare power back to the grid to take advantage of resell tariffs. So if you think about it, the inverter has to, as @FixAMess points out, synchronise with the grid. If the grid is at 228V, then 228V is what we must send back. So this synchronisation requires drawing a little power from the grid as a sample.
  6. This is such cool advice from @Sarel. I can't say my system has failed me, but it is right on the edge, and so compromises have had to be made (hot water bottles instead of electric blankets for example), and it hasn't taken my off grid. I pretty much am on a day like today (just as well because we won't have grid for a total of 5 hours today), but if we have 2 or 3 consecutive overcast days then I'd have to start using some grid power. And it's going to be hard to extend this system, although it meets our current needs. I could have done my homework better, but I didn't know what homework to do.
  7. THIS! I find it an on-going struggle. I thought that there would be a learning period - including us learning what to run when - and then routine would set in. But no... First problem, and I blame myself for it, is that it didn't occur to me that the thing would be load limited on the output side. So we do run our dishwasher, our kettle, our hot water heating, our microwave on the backed up side, but we can't run them all at the same time. Doh! Of course there's a limit. Why didn't that occur to me? I should have clarified this at purchase time. Anyway, that has been solved by the "rule of two": Look around the kitchen and take note of the microwave, the dishwasher and the kettle. Are two of those on? Then you can't turn on a third. This is not a technically perfect rule (the dishwasher doesn't draw a lot for it's entire run time, and the rule allows headroom for the heat pump) but it gets the job done. But 2 years later I still have conversations that include the sentence "but the sun is up". That can mean anything from "I have to wear sunglasses inside the house" to "I can see a crack of light through the curtains." Well yes, the sun is above the horizon, but what about all those white fluffy things up there too? Again I have a rule: don't do stuff before 8 am and after 4 pm. There's more science here (or more demonstrable science). I can show that on a nice clear day like today we are getting about 700w of PV at 7:30, but around 2 KW half an hour later. And I can show that on an overcast day those figures go down a lot. But somehow this doesn't sink in and I get regular reminders that "the sun is up". Well, it IS above the horizon, and we don't have to drive with headlights on, but that doesn't necessarily mean that we are getting a lot of PV. Because what is electricity really? It's a convenience. We expect it to just be there for whatever it is we want to do. And compromising on that goes against the grain a bit. So this is a very good question. Because for some folks having to change their lifestyle is not an option. They don't want a "rule of two". If they want to shower at 2 in the morning and then run the espresso machine and heat up a convenience meal which they will eat whilst chillaxing by watching the tropical fish in the heated tank... well at the very least a system that works for me won't work for that guy. In the meantime I've had to learn how to operate the dishwasher.
  8. Hi all. I am considering one of these leaf catcher covers for my swimming pool. As far as I can tell they are made from 55% shade cloth. So two questions for those of you who have experience with such covers: 1) Do they drop the pool temperature? 2) Do they significantly reduce evaporation? Thanks
  9. Thanks for the clarification. That's a disgraceful state of affairs.
  10. That won't get you off-grid. Assuming it gets you through the night (may, may not, you have to try it and see) what happens when you have 2 or 3 overcast days in a row? The battery will not get properly charged, will run down and then? Going off-grid just with solar and batteries can't be done. OK... maybe it can be, if you have a lot of batteries and a lot of panels and a system that can handle the batteries and panels. So you're going to need a generator, or to go for a hybrid solution and retain the grid connection. If you go gennie then ideally you want a system that can start the genny up for you, in case the batteries run down at 2 in the morning. Reducing your bill and your dependency on the grid can be done reasonably. Going all the way off-grid is more costly.
  11. First identify the problem. There hasn't been any load shedding for some time now (which surprises me, given the problems Eskom have been having, but there it is). Unless your friend's factories are in one of those areas where Eskom are practicing "load reduction".
  12. Many, many years ago I fixed electronic watches for a living. You can imagine the volume of flat batteries that our workshop accumulated. Because we did SA repairs for a prestige brand we couldn't use just any old battery. We had a list of batteries that met the brand's requirements. Some watches used the now common 3V lithium cells, but quite a few used the little 1.5V cells (think hearing aid batteries). These latter, if we used the approved items, had a small quantity of silver in them. Serendipitously we learned of a company that would buy our old batteries for recycling. They would pay us according to the quantity of silver they recovered. They would also only take consignments of a certain size. This makes sense - it's way too much trouble to try and extract that small amount of silver from a single battery. When we had several thousand old batteries we stuck the drum containing them into the back of the company bakkie and took them to the recycling company. They showed us around. Essentially they had a small electric furnace and they would melt the batteries down and extract the molten silver. You can guess how this ends. We had decided that we'd use our new found wealth to buy cool drinks for the workshop fridge. Well... the amount of silver eventually produced you could put on a finger nail and we got about enough to buy a 6 pack of coke. What was left over was several kilograms of slag which was taken down to the municipal dump. We tried to get them interested in old circuit boards. We didn't replace whole boards very often, but we occasionally did and there was gold on those. But they said that due to various laws extracting and then selling silver was one thing, extracting and selling gold quite another, so they weren't interested. This was back in the early 80s when very few were thinking about the amount of junk we generated, but I will never forget that small bead of silver and that much larger lump of slag. A lot of so-called "recycling" is just extracting the tiny valuable component of whatever it is and dumping 99.995% of the original. You don't actually recycle much. Round about the same time we heard about another company (still there as far as I know) which "recycled" motor oil. They bought it from you for a very small amount. They said the oil itself didn't actually degrade, but the difference between old oil and new oil was the sludge that represented the wearing of the moving parts of your engine. So they would separate out most of the sludge by gravity, get the rest with magnets, do some filtration and add some sort of detergent and, they said, you could use this when servicing your car. It was cheaper than any brand name. A couple of my colleagues bought this product (they serviced their own cars) and said it seemed like a good product but there was no real way of knowing. The company also recycled 2 stroke oil and resold that for use in motor bikes and lawn mowers. So with the oil there was still all that sludge to be disposed of, but I'm inclined to believe the ratio of what could be reused and what made it's way to dumps and groundfill was a bit more skewed to the re-use side. Sorry to pour more rain on your day.
  13. Thank you so much. So the question is what timer switch is that? And does it switch the power itself, or, as it appears to me, does it switch relays? In which case which relays are in use because with the DC from the panels there is a chance of arcing. But thanks again. This would give me significant extra power and flexibility.
  14. There is that, but that doesn't cancel out the municipality's or eskom's interest in what is being connected to the grid. Their interest is legitimate and so their inspections are justified. What we should want is the rigour, with the necessary paperwork, but with clean finances. Which is what we up here on the highveld are told happens in Cape Town, but I hear lots of complaints from that part of the world about the municipality overstepping the mark. There's a middle ground somewhere.
  15. Power suppliers (Eskom or municipalities) have a legitimate interest in what is connected to the grid, so in principle I don't mind them have mechanisms in place to find out who has something connected to the grid and whether or not it's properly connected. I know of people who have built their own solar systems. It's easy and cheap! That's what the tell you. It might be dangerous to them - which is one thing - but it might also be dangerous to a sparkie who believes the juice to be off. Same as people with generators. Sure they should be allowed to run a genny, but they shouldn't be allowed to connect it to their house any old how they please. There has to be some regulations (for the safety of the grid and of people) and some enforcement of those regulations. But that's what it should be about: good operation of the infrastructure and protecting the public.
  16. Ok... I'm interested in this. I have half my panels facing east and mostly this works, but every now and then I get an overcast morning and a clear afternoon and I can lose out a bit. Plus if I had west facing panels I could take advantage of the PM sun and run a 2nd geyser. Simply switching from one string of panels to another hadn't occurred to me. Is it not possible to have a timer do the switching? Because I am lekker forgetful and can see myself switching from E to W one afternoon and then leaving things set that way and running out of battery the next morning.
  17. So I have 10kw/h of life batteries and the accompanying electronics. One day (not next week, but one day) these are going to need replacing. I doubt I can just chuck them in the wheely bin. So where do they go? I'd like to dispose of them responsibly. Other problems. 1) how will I know it's time? I presume they gradually last less long (ie don't get through the night anymore). 2) will there be anything compatible with a 10 ish year old inverter?
  18. I hear what you're saying, but I still have to try and recover the cost of the entire installation. Saying my panels are paid off but the batteries will still take a while still leaves me with the same spend to recover/justify.
  19. A reccomended course of action is to not shoot, not to resort to the courts, but to file a complain with the Civil Aviation Authority. Apparently they have real teeth and in the last couple of years have hit several indiscrete drone operators with 50 grand fines.
  20. I just had a look at that. Before the rinderpest, owners of a property owned all the air above it and all the ground beneath it (they could sell or lease those rights, but the rights were theirs to lease or sell). But all over the world that made commercial air travel a difficult proposition, so laws have been changed or, if you prefer, rights have been eroded. One revision was made in 2018 specifically to deal with drones. Drones, with permission from the relevant authority, may overfly your property at a "reasonable" altitude. We don't know what "reasonable" is, but there is another law that basically says that 50m is trespassing (theoretically this may make it impossible for your neighbour to fly his drone in his property as he has to keep it 50 m away from your property). Presumably you can permit the drone operator to operate within that 50m limit, but again this is your gift. Checking for solar panels can be done at a greater height than 50m. You can see mine on Google Maps, and they didn't have a drone snooping around my property with me trying to bring the varmint down with the pool net. Current laws also rule out shooting down a drone (a net may still be an option) or anything else. If you discharge a firearm in a residential area that is an immediate offence. Obviously if you have a good reason then you will escape a penalty. If you shoot some guy coming at you with a chain saw then you'll be OK, if you shoot into the sky because you're vrot and you want to show your new toy to your buddies then you will be in trouble. Shooting down a drown (even within the 50 meter limit) is a no-no. That all said, we should be concerned about encroachment of our privacy by municipalities. Though read your property deeds carefully and note how many organisations have servitude rights*. Note how often the word "reasonable" crops up. Personally I'm in favour of a reasonable (haha) amount of this. None of us live on an island. ADSL got a very bad rep in my neighbourhood, but the problem was that some people had very overgrown gardens and trees that were fouling Telkom's cables. The cables are Telkoms, they have servitude rights, but the owner says "my property, I say who can come in and who can't." Telkom's offer in my area was that they would visit properties known to be problems or even just carry out an inspection if you wanted one - at their cost, at a mutually agreed time, with minimal trimming of branches that were actually fouling lines (not felling of trees). One of my neighbours said "no" and called the police and ADT. The result was that the rest of the street had slow, unreliable ADSL connections, because of one unreasonable person. City Power in Johannesburg have had trouble with trees planted on private properties but which then are not kept in check and foul power lines. They come to lop of the branch and next thing you know some property owner is threatening them with his dogs, his lawyer and the Constitution. So whilst I think that we need to be wary of the state/city's inclination to take liberties, we need to see the big picture as well. * a while back I wanted to improve the storm water drainage in my driveway. If I did it by the book I had to get permission from nine separate organisations, all of whom may have had cables or pipes across my driveway or some other reason for having servitude. All an oke wants to do is dig a trench across his driveway to divert rain water, but it's not that simple. I notice that other people in my area have not done things by the book and made simple concrete structures which just divert the rain water onto their neighbour's drive way. That doesn't seem like a better scenario to me.
  21. You also need to get the COC updated and then give a copy to your insurer. Otherwise if the worse comes to the worse, Mr Loss Adjuster will come along, find all this wiring that's not mentioned on the COC they have (or the last COC issued) and then you have not described the property accurately and then their obligation to you vanishes.
  22. When I bought my system I did a calculation on a little piece of paper and figured a 7 year payback (given annual escalations > 10% by Eskom). That was the cost of the system against what I wasn't going to run up on the meter. I know longer think that will happen (for one, stupid me didn't factor in overcast days), at the very best I will break even just in time to splash out on new batteries. However, this doesn't mean my wife is unhappy. Firstly the savings increases year on year as the tariffs increase. Secondly, since installation we have always had power, the lights have always been on, the fridges and the deep freezers stay on and so we don't lost contents (and I can always get a cold beer), we never miss Strictly Come Dancing. These are things that we can't attach a rands and cents value to and so set off against the purchase price of the system, but they surely are worth something. So I think in pure rands and cents terms - where the only saving you can measure is on your meter - it's difficult to balance the books, but there's the advantages that I've described above, and if reducing your carbon footprint is worth something to you then there's another thing that is worth something.
  23. Where do you live? Who supplies you with electricity? And how much of that monthly amount is fixed? If you live in Johannesburg, are supplied by City Power and are on the regular post-paid tariff then about R700 a month is flat fees and you are paying 1300 to 750 for actual electricity - and that's what you can save.
  24. Where do you live? Who supplies you with electricity? And how much of that monthly amount is fixed? If you live in Johannesburg, are supplied by City Power and are on the regular post-paid tariff then about R700 a month is flat fees and you are paying 1300 to 750 for actual electricity - and that's what you can save.
  25. My heat pump is a few years old. At the time I had it installed I wanted a solar geyser (I'd had one at my previous property) but there was no way to position the tubes so that they would face north (according to salesperson. At my previous place of abode they'd built a framework and mounted geyser and tubes on that, he told me that's not allowed in Jo'burg anymore). This then led to "ok, how much is it going to cost?" The answer was that there was not much in it in terms of putting a solar geyser on the roof or hooking up a heat pump to my existing geyser. To be clear, this is a heat pump to heat a 200l geyser, not to warm up a swimming pool a bit. OK... so maybe solar geysers got cheaper in the meantime, or you are proposing just tubes on a roof feeding an existing geyser. I think it's important to understand what varieties of fruit we are comparing. What you say about relative efficiency makes sense to me. What I don't get with the heat pump is loss of water due to the water getting too hot and a pressure relief valve sometimes having to pop and send lots of scalding hot water down the roof and into the gutters. What makes the heat pump work for me, I think, is the improvement in efficiency V a common or standard geyser (which, in turn, means I can run it early AM off my batteries), and that I can use the timer to just run it at certain times of day which suit our lifestyle. RE Cost. Yes... the heat pump is more expensive than a regular geyser (or even a geyserwise as far as I can tell). It's like so many of these things - you have to play the long game and bet that over 7, 8, 9, 10 cars you will make the money back and then start saving.
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