1 minute ago, Bobster said:

(but wasn't everybody taught at school, for example,  that for every action there is an equal and opposite reaction?)

hahaha, it was called 'pakslae' 🙂

22 minutes ago, plonkster said:

It's fun thinking about it though.

It definitely is.

As the saying goes: Everyday I know more and more about less and less.

 

Edit: I just realized now, I only mentioned the Mandelbrot set, the video covered : the logistic with its connections to fluid convection and neuron firing, definitely worth a watch.

Edited February 24, 20206 yr by PJJ

4 minutes ago, Gabriël said:

which reminds me, who might be able to help me with back to utility voltage settings for the pylontech in order to not exceed say 50% soc?

Isn't this a function of the inverter? I have a Goodwe inverter, and the minimum SOC for the batteries is configurable, but on the inverter, not on the batteries.

This makes sense: The BMS reports SOC to the inverter. The inverter then decides to carry on discharging the batteries or not.

2 minutes ago, Bobster said:

Isn't this a function of the inverter?

you are right, at present mine is set to 49volt [setting 12 axpert 5kv, battery to utility voltage] which i believe is slightly too high and keeps the pylons within the upper limits of soc, maybe 80-100%. so i will start with 'ye olde tinkering' game again in order to get them to about 50% soc.

 

21 minutes ago, Gabriël said:

hahaha, it was called 'pakslae' 🙂

I'm constantly surprised by this. Maybe there are things that are assumed to be so fundamental that nobody bothers teaching them anymore. "Oh EVERYBODY knows that", and so it drops out of the syllabus. 

By the time I was 12 I knew about, for example, process of elimination, and I use that nearly every day in my job. I have taught the principle to youngsters and you see their eyes light up in wonder that such a method exists.

Same generally in my line of work - computer programming. Nobody flow charts any more. Nobody draws up truth tables. Boolean algebra (what we young wags, encouraged by a lecturer, referred to as "booles**t)? What's that?

I used to work for a man who was a chartered accountant by training, although he made his money in software. He asserted that in any activity there are fundamentals, and if you master the fundamentals then you can meet all future challenges. EG he said that THE fundamental of all accountancy is double entry, and that if you truly understand double entry there is no accounting problem that you cannot solve.

He also expected people with job titles to know certain things. We once had a customer phone and tell us what a pile of rubbish our system was because the trial balance didn't balance. He asked what the discrepancy was and immediately said "you have transposed two adjacent digits when you captured one of the entries, please check what you captured against the source documents." They were not happy and insisted that he send somebody out to fix it.  He made a deal that I would go to their offices and check, and if it was he had had told them to check then they had to pay for my time.

Off the phone he explained to me that the discrepancy was a multiple of 9, and every accountant/book keeper should know that if your error is a multiple of 9 then the most likely cause is that you transposed two adjacent digits EG the amount is 1234.56 and you entered 1235.46.

He was right, and they were out of pocket and chastened.  He had no mercy on them because the guy who called to complain was a CA with 30 odd years experience and so, in my boss's opinion, should have seen the error and realised what the problem was and got his staff to recheck.

Edited February 24, 20206 yr by Bobster

11 minutes ago, Gabriël said:

you are right, at present mine is set to 49volt [setting 12 axpert 5kv, battery to utility voltage] which i believe is slightly too high and keeps the pylons within the upper limits of soc, maybe 80-100%. so i will start with 'ye olde tinkering' game again in order to get them to about 50% soc.

 

If it's a Goodwe ES I can help you with specifics. Anything else and I can't.

3 minutes ago, Bobster said:

I'm constantly surprised by this. Maybe there are things that are assumed to be so fundamental that nobody bothers teaching them anymore. "Oh EVERYBODY knows that", and so it drops out of the syllabus. 

By the time I was 12 I knew about, for example, process of elimination, and I use that nearly every day in my job. I have taught the principle to youngsters and you see their eyes light up in wonder that such a method exists.

My dad, when working, used Pythagoras's theorem nearly every day in his job. Indeed had a loop of rope with knots at 3, 4 and 5 yards so that he could check the squareness of anything that he needed to check for squareness.

I still remember that some old hens cackle and heckle till old age and still occasionally use it.

3 minutes ago, Bobster said:

By the time I was 12 I knew about, for example, process of elimination, and I use that nearly every day in my job. I have taught the principle to youngsters and you see their eyes light up in wonder that such a method exists.

Something I use all the time is reductio ad absurdum, which is also not taught on any level. You assume that the contrary is true to the statement you want to prove. If this contrary assumption reduces to an absurdity, it proves the original statement.

Then there is another one, and this is a big one: There is more than one way to get to the answer, loosely deductive, and inductive/abductive reasoning, or I can also say there are two approaches, evidential or presuppositional. I can either start with the evidence and reason forwards towards a conclusion OR (and this is where the wheels fall off), I can start with the observed result, then postulate possible causes for it, and infer backwards which one is the most likely cause (some probability is involved in this one). This latter one is often used by doctors who need to work backwards from a symptom, or a detective who have multiple suspects.

re the posts just preceding... just yesterday the importance of the fundametals came to my mind and there is one good example where all scholl kids in the ussr and i believe japan had to learn chess. i remember playing chess and the way in which it helped you to think correct - although i never was good at it, it nevertheless helped.

and yes, @Bobster, you mention logic - how many people lack the basics in that department... we had a  book by copi way back in the 70s

18 minutes ago, Gabriël said:

re the posts just preceding... just yesterday the importance of the fundametals came to my mind and there is one good example where all scholl kids in the ussr and i believe japan had to learn chess. i remember playing chess and the way in which it helped you to think correct - although i never was good at it, it nevertheless helped.

and yes, @Bobster, you mention logic - how many people lack the basics in that department... we had a  book by copi way back in the 70s

It's not mandatory everywhere, I guess.  I would think that for programmers boolean logic is essential, but not, for example, for bricklayers or plumbers. OK... it's handy too for certain types of electronics. EG you have 5v on that pin and 5v on the other pin and it's an AND gate and so on the output side you should have...

I played chess myself, but I never feel like I learned anything from it other than to play chess. But this maybe down to personality traits. 

I'll also add, having got on the high horse here, that I studied programming at Technikon (at it was in those days) and after I was finished I gleefully chucked out of the window all that stuff in text books that old fogies had thought up, then 2 years later realised that some truths are eternal and got my text books out again.

3 minutes ago, Bobster said:

I played chess myself, but I never feel like I learned anything from it...

i think that is my point, its like walking, an exercise but of the brain - you don't really do it because you want to become a 'walker' [if there is something like that...] nor really to get from a to b, but just to enjoy a bit of fresh air, greet the neighbors, unload etc - but now the benefits start to come in, better digestion, better sleep, relaxed, general improvement of health and endurance etc and this has a positive influence on your life as well as in society per se. quite the contrary to becoming a slouch potato automaton in front of a tv [aka the modern trojan horse] 🙂

19 hours ago, Bobster said:

I'll also add, having got on the high horse here, that I studied programming at Technikon (at it was in those days) and after I was finished I gleefully chucked out of the window all that stuff in text books that old fogies had thought up, then 2 years later realised that some truths are eternal and got my text books out again.

Taking a flyer here. I still have all the text books bar one. I can only assume I loaned it to somebody I thought I could trust, but I can't think who because I steadfastly held on to the rest.

Anyhoo... maybe somebody knows this book. It was a McGraw-Hill publication and it was all about logic and logic chips. Building up from simple gates (AND, NOR, NOT etc) to latches and flip flops and eventually to a simple processor. It was written with beautiful clarity, and even though I was used to flip flops and latches I learned from that book and in terms of understanding binary logic and how that applies to computers it was invaluable. 

But I can't remember the title or the author (I recall that he has written several books used in colleges and universities all over the world). Any ideas? I would seriously go hunting for a second hand copy if I knew the title.

4 hours ago, Bobster said:

But I can't remember the title or the author (I recall that he has written several books used in colleges and universities all over the world). Any ideas? I would seriously go hunting for a second hand copy if I knew the title.

You feel about that like I feel about my HP 20S calculator. I put it on the roof of my car one day and drove off with it, losing it forever. Still upset about that. I would actually buy it secondhand if it came up...

23 hours ago, Bobster said:

But I can't remember the title or the author (I recall that he has written several books used in colleges and universities all over the world). Any ideas? I would seriously go hunting for a second hand copy if I knew the title.

It has all come back to me. Or at least the author's name did. Andrew Tanenbaum. Once I got that it was a quick google to find the book. $100 dollars plus shipping for a used copy from Amazon 😮

Edited February 26, 20206 yr by Bobster
spelling

1 hour ago, Bobster said:

Andrew Tanenbaum

Oh, the Minix guy? I have a book on OS design from him too. Also interesting to read up on the interaction between him and Torvalds 🙂