Posts by rob

41) Questions and Answers : Windows : Computation error when BOINC halts (Message 69352) Posted 17 Jul 2023 by rob Post: There is a problem with a batch of CPDN tasks which affects some, but not all users - lots of discussion on their "number crunching" forum https://www.cpdn.org/cpdnboinc/forum_thread.php?id=9149 It is particularly prevalent with tasks starting with "WAH2_EAS2", but may not be limited to them. Taking care to shut down BOINC (not just close it) before shutting down the computer does appear to improve the situation a little. (Windows - right click on BOINC in the taks bar, select "EXIT", the "stop all running tasks".)
42) Message boards : Number crunching : Credit Question Answered (Message 69350) Posted 17 Jul 2023 by rob Post: Credit is not a "free bonus" to either the project scientists, or those running the applications on their computers. Even using the standard credit system requires configuration and monitoring, plus disk space to record. Also there is the, admittedly small, extra data that has to moved from the client (you and I) and the server. While the "standard" system works fairly well on the average project, where tasks minutes to hours to complete, it falls over for projects like CPDN which take days or weeks to run. For the majority of projects awarding credit on completion is OK, there's no substantial delay, but for long duration tasks it becomes a real pain - thus CPDN came up the trickle awards system, which isn't perfect, but it does mean that users get credit as work is done. Does credit work? Credit has, on its own, zero value apart from bragging rights. I know there have been schemes to monetise credit in various ways, but they don't appear to pull in many users. So, why have the number of BOINC users declined in recent years? Many reasons, perhaps the biggest are the lack of headline grabbing projects, and the low stability of some of those big projects.
43) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69314) Posted 13 Jul 2023 by rob Post: I give up. I've no idea at all what sort of weird nonsense your side of the pond uses for solar panels then. In reality pretty much the same panels as you do, leaving out the "toy" 6v panels (10 cells), and the highly suspect "12v" one (which may have 20 cells, but the suppliers are very cagey about how many they really have). We then move on to the 18v (30 cell), and then ever upwards. Obviously the mains side of our inverters is somewhat different to yours being 230v to neutral (single phase), but the low voltage chargers and the like are "all but identical". On my boat I have a pair of 60 cell panels, wired in series and feeding into an MPPT controller, which is configured to keep the boat's house battery bank properly charged when unplugged from a shore supply (provided the sun is bright enough - which is a problem in the UK for much of the year. Total aside : - Where does one get a 57.3 cell panel, I can only find 48.9 cell panels ;-)
44) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69298) Posted 13 Jul 2023 by rob Post: Well, there's the fact that one of the neighbour's houses needed to have substantial repairs due to the party-wall (terrace houses) cracking BEFORE the demolition may well have been damage due to being undermined is immaterial..... DO NOT comment on things you know nothing about, doing so only makes you look even more foolish. END OF CONVERSATION
45) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69290) Posted 13 Jul 2023 by rob Post: In this case laws are there to protect those who would be lawless (and the lawless from their own stupidity). The penalties for breach of planning law are quite extensive. - Thousands of pounds in fines, having the alterations removed under a court order - at the expense of the person who commissioned the modifications. If the modifications have been detrimental to the structural integrity of the building then demolition may be the only way forward, again under a court order. We had this in Tamworth a few years ago where an "owner occupier" decided to extend a small house up. He ignored a number of planning enforcement notices and ploughed on in his own arrogant manner. A summary of the works: up - added an extra floor by replacing the roof; down -dug a basement under the house and much of one of the gardens; and outwards -built an extension into the garden that didn't have the basement. Silly idiot argued that, as it was his own house he could do what he liked with it. He ended up with a monstrous fine, having to pay for the demolition of his house and the two adjoining houses due to them being undermined. His mortgage company cancelled his mortgage and required "full-term settlement" (from what I can grasp this means they wanted the principal plus interest at some assumed rate for the whole duration of the mortgage).
46) Message boards : Number crunching : New work discussion - 2 (Message 69247) Posted 12 Jul 2023 by rob Post: Well it survived last night's shutdown and this morning's restart. Onwards and upwards - ~6% done in ~8 hours.
47) Message boards : Number crunching : New work discussion - 2 (Message 69242) Posted 11 Jul 2023 by rob Post: I will be stopping and restarting the computer, so I'll keep you posted. It will be interesting as there are a couple of differences, one is I'm only allowing CPDN to run a single task just now, and also these tasks are from a different data set to those that were failing in minutes. p.s. Still running after 4.5 hours, but fingers and toes still crossed for the next 9 days of run time which is more like a couple of weeks clock time.
48) Message boards : Number crunching : New work discussion - 2 (Message 69240) Posted 11 Jul 2023 by rob Post: Thanks Glenn, I had a feeling there was a difference between the EAS & NZ data sets, but wasn't certain. It will be interesting to see how the "new, smaller" EAS data sets behave - hopefully better than the "old large" ones that have been so much trouble for so many (I'm so glad mine all failed in a couple of minutes, no several days).
49) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69237) Posted 11 Jul 2023 by rob Post: It's easier to seek forgiveness than permission. If only that were true in the case of deferred planning permission, it's way more expensive, time consuming, and is there is no guarantee that it will be granted. For some authorities the "success" rate is about 5%, which means 95% of the time there is a court order to revert the building to its stat before the works were undertaken, and if the individual doesn't do it then the council is able to engage contractors, at the property owner's expense, to do the work.
50) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69236) Posted 11 Jul 2023 by rob Post: Council inspectors do have "beats" - the whole of the council's area. They do walk/drive around, chat with folks in pubs, watch where traders' vans are going, where building materials are being delivered etc., and they do regularly catch people like yourself. So, of you want to be cavalier with the law then it's on your own head when you get the "knock on the door", followed by the court order to revert your property to its state before you undertook the illegal works. That can cost thousands of pounds in fines and building works. Most folks would rather stay within the law and pay the pittance to get planning permission & building regs (well a pittance compared to the total cost of the works).
51) Message boards : Number crunching : New work discussion - 2 (Message 69230) Posted 11 Jul 2023 by rob Post: After a run of wah2 ea25 tasks all of which failed in the first couple of minutes I've now got wah2 nz25 task which has run for 27 minutes and counting. Fingers and toes crossed for the next few days running and a successful conclusion.
52) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69227) Posted 11 Jul 2023 by rob Post: The Scottish government publishes the rules, which are clear as to what does and doesn't need planning permission. As a home owner or builder planning an extension one should work through those rules step by step and if the "thought of" extension falls outside any one of those rules then either rethink the idea of have a chat with the planning people for clarification (which may lead to the idea being accepted), but going ahead with an extension that falls outside the rules for presumed permission then one runs the risk of having to apply for retrospective permission, which can be very expensive (even more so if it is rejected and the extension has to be demolished - who wants to pay twice for the same job?).
53) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69225) Posted 11 Jul 2023 by rob Post: And it would appear we don't have a right to either. Makes a mockery of buying a property with a nice view. You have a right to a view, hence it is listed as being an allowable objection to a planning application. I thought building regulations were only for selling a house. For example I only have a fusebox, so that would be noted on a buyer's report. Even then I don't have to upgrade it before sale, it just might increase the sale price. Well, you've learned something - building regulations apply to building works not to sale. The latest electrical installation regulations apply to "new works" and are quite specific in how they apply to additions and amendments to the existing part of an installation - crudely, if you add something that is covered by the new regs then you have to have the existing installation inspected and brought up to a defined standard. I didn't ask for permission when I had mine changed from gravel to monoblock. No idea if I was supposed to. Not the sort of thing I care about, or even suspect I'd have to tell anyone about. It all depends on where you are, when the work was done and the attitude of the local authority. Worst case is having to apply for retrospective permission, having that refused and then having to revert the drive to its "former gravelled glory". A couple of my neighbours have suffered this indignity, but when that officious individual in the planning department moved on the new occupant of the post has a more pragmatic approach. I had great fun when I decided to change my drive from decaying tarmac to a "pant covered tarmac drive" - the process started under the "old" person, but the "new" person came out and said something along the lines "I can't see any problem with you adding more green stuff, carry on not spraying weed killer everywhere", so guess what, I don't spray the drive.
54) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69223) Posted 11 Jul 2023 by rob Post: Why were you notified? Quite simply because there is a legal requirement to directly notify everyone within a certain distance, that distance varies according to the nature of the development, its location. There's a legal difference between "loss of view" and "loss of light" -crudely the view is what you can see at a distance, light is your property being shaded, in whole or in part, by the new works. When it comes to electrical installations those are covered by the building regulations, and the wiring regulations, in place at the time of constructing the building or extension. The rules and regulations around drainage are just plain confusing and are ever changing. In parts of the UK you have to apply for permission to resurface one's drive but can build a new one without permission; in other parts you need permission for both; and to add to confusion there are various definitions of the area considered and where the run-off water goes.
55) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69211) Posted 10 Jul 2023 by rob Post: Just one fairly minor correction. (1) As noted, DC power conversion circuitry was not available when electricity first showed up in mains systems. AC can be stepped up and down by a transformer. The model for DC was literally "A power station every few blocks." By the 1880s when the debate took place the were well established AC and DC machines, what was lacking were sensible converters between the two, particularly from DC to AC. True there were rotary converters (one shaft with a DC motor at one end and an AC generator at the other), but they were very inefficient and large for what they accomplished. The other big component that was lacking were DC breakers of a sensible size and speed. DC will grow arcs to quite substantial lengths, and will not self extinguish. Such breakers that existed were massive and even the somewhat prone to burning themselves to the ground in damp or dusty conditions. One thing you didn't mention, and this may have been a critical factor, Edison didn't have the financial clout of Tesla and his baker Westinghouse who had a big pile of money.... As to getting systems stable with a large number of "free range" inverters and one big generator. One can tell when the various standards committees involved are sitting by the sales of headache cures in the area. There are so many external factors that are outside their control (direct or indirect) that the meetings tend to be very drawn out and heated. The most obvious are the existing network structure and topography, local climate and weather, and geology..... This is going to be a major consideration with the increasing trend for new properties to be legally required to have solar panels with their associated inverters connected to the grid and a long established town to grid connection.
56) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69208) Posted 10 Jul 2023 by rob Post: Why do you think its a VERY SMALL lead - big leads (more than a couple of degrees) can cause some very interesting (or exciting) results. A small over-voltage is in effect a small lead, and can be used if you have very good voltage control in the inverter coupled with a good understanding of what the grid is doing on a cycle by cycle basis.
57) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69207) Posted 10 Jul 2023 by rob Post: No, they are neither constant current, nor constant voltage, devices, you need to look at both the voltage and current curves against light level for the panel under consideration. The best controllers work by maximising the power delivered at a given light level. But they will NEVER deliver more power than the product of maximum power and maximum voltage. Since the device is quoted as a "12v" system with a working current rating of "5.76A" that's the limit, just under 70 watts. Even if this was an 18v system it this panel would only be capable of delivering about 104 watts - a long way below the suggested 250w. I could continue shredding that advert, but there are so many inconsistencies in it (basically lies to make fools spend their money with a gang of fraudsters) that it would be a pointless exercise as you've already been conned and are in total denial.
58) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69204) Posted 10 Jul 2023 by rob Post: You need to have a look at one of the many UK & Europe grid watching sites to see what the real grid is doing in near-real time. A lot of effort is put into managing it within the defined limits, and al "major" generators work together to keep it stable. The same even applies In countries which have many local grids that are not connected to each other great effort is made to ensure that the frequency stays within the legal limit, but each non-interconnected grid may be (probably will be) running at its own frequency and have it's own drift rate. Most "good" inverters have over & under frequency detection and shutdown systems. This is often one of the first victims of cost cutting on cheap inverters. If the grid frequency goes out of range an inverter (or separate transfer switch) will assume there is a grid fault and disconnect from the grid and revert to local control. Generally the inverter or transfer switch will continue to monitor the grid so an auto-reconnection can be made - auto-reconnection is often a user configurable option. Phase difference will determine which way the power is flowing between your inverter and the grid. A small lead will allow power to be fed into the grid by your miniscule (in grid terms) inverter, a small lag will cause power to try to feed into your inverter, which may not be good for its health (expect the magic smoke to escape).
59) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69203) Posted 10 Jul 2023 by rob Post: and in the "product description" section: Current Rating 2.6-5.78 A Voltage 12 V Now the output power has dropped to 69.36 w (which may be more realistic for the panel size) No, it's just wrong. No panel is 12V. They vary with the brightness of the sun. Let's try and explain this to you: Voltage - probably the output from the controller which should be constant, after all that's the one that charges any batteries or supplies the other loads (such as inverters). The output from the panel with vary with sunlight, but the vast majority of suppliers quote the maximum voltage (typically for small panels about 18v). Now current - in the range 2.6A to 5.78 amps. The latter is the maximum the system can deliver on its output terminals, not the panel output. So we can work out the REAL power the system can deliver, and that is system voltage multiplied by maximum current, and that equals 69.36 watts - all that power has come from the panel, and as power is "constant" (in this constant) all that power has come from the solar panel. On a dull day the power from the panel will drop significantly, and so the output from the system will drop, and it would appear there is a lower current limit of 2.6A - this implies there is a bit of under voltage protection somewhere between the panel and the output from the controller and this causes the system to shut-down at low light levels.
60) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 69200) Posted 10 Jul 2023 by rob Post: Many multi-inverter systems do require a master to prevent (or at worst minimise) all the inverters around looking for the "right" frequency. Looking at the spec for the OutBack Radian inverters suggests they do have a master inverter and a number of "slaves" - everyone of which should synchronise to that one. So no "frequency pollution" (that's a great description of what happens when AC power supplies don't synchronise properly) within the local grid (your shack),or to the big, outside grid. The how part is quite interesting. It really depends on a couple of design decisions. There are two considerations, first is the grid frequency, this is quite easy to establish, the second is phase difference which can be fun - a grid tied inverter will generally be slightly in advance of mains (fraction of a degree). These can both be done in hardware or software or combinations thereof - the inverter designer will have made the choice some time ago. The question about lots of inverters (in different locations and of different types) is one that has been asked quite a few times over the years. The answer is actually quite simple - scale. The main supply to the grid (the big generators) are so much larger than all the inverters so, in terms of frequency, are insignificant. (but who knows in the future when there are thousand more inverter systems "grid tied"?).

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