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Posts by Mr. P Hucker

Posts by Mr. P Hucker

1) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70806)
Posted 11 Apr 2024 by Mr. P Hucker
Post:
I disagree, solid can miss the screw altogether, with stranded something will grab.
"Not working at all" is a better outcome than "Being partially connected, yet not having the full wire size connected." The first is easy to troubleshoot. The second works, until it overheats the few strands that are connected and causes problems.
But those strands are only mm until they touch the rest. Resistance is also proportional to length.

Time is a limited resource.
I agree, that's why I do it properly the first time, instead of constantly having to go back and check to see if I screwed up.
But doing it properly takes a lot more time and money than a quick check and alteration if required. Most time the guess was correct anyway. If in doubt just use more than you think you'll need, it future proofs it.

Nonsense. If you have a 5kW heater and only 2.5kW is needed to keep the room warm, it will cycle on/off at 50% duty cycle.
Fine, and entirely irrelevant. The wiring still has to handle the full rated draw, safely, for extended periods of time.
Only if you know it will ever be used in such a way.

The general design of wiring and circuit protection, per what I'm familiar with, is that any wire must be rated to handle the full current the upstream protection device can provide - so if you have a 20A circuit breaker, the wiring had better be able to handle 20A indefinitely. The continuous load derating factors in here too.
In the UK they have some stupid thing in the regs (not sure why you call it a code, it's not a puzzle to solve) saying it's ok to have a double outlet which can take 20A total, even though it's a pair of 13A sockets. They claim it's unlikely someone would ever use both fully.

All you need is "This is 20A wire. Deduct 20% if under insulation, deduct x% for this, y% for that."
As clearly stated in the various charts and correction factors you refuse to consider. "12AWG Copper 90C XHHW-2" is sufficient to answer all those questions. You're just insisting on your right to not have to bother.
Why not write it on the cable reel? Suitable for x A in this case, y in this case and z in this case.

And there's no point in a table for all wire, as all wire is different. If I try to look up such a table, I find several different answers to the same question!

What percentage of people die in a building fire? Probably a billion times less than a car accident or cancer. You sound like the UK government, concentrating on the wrong things.
US fire deaths are about 3800/yr, automotive fatalities are around 38,000/yr, give or take on both numbers. So, 10x difference, a couple orders of magnitude less than your guess.
I never said it was accurate, I just said it would be vastly more, which it is, so all efforts should only be on cars. No point in helping the eleventh who die in fires.

And a good reason that the fire deaths are fairly low is things like the NEC, that dictates wiring standards in a fairly conservative manner, vs "Do whatever you want and hope it doesn't catch fire."
Which only hurts those who choose not to be safe.
2) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70800)
Posted 10 Apr 2024 by Mr. P Hucker
Post:
If the problem is that your wiring is undersized for the job and the bulk of the wire is getting hot, this will work. If the problem, as you seem to imply, is your connections getting hot, you've got a bad crimp job, an improper connector for the job, or the wrong sized connector for your wire gauge (connectors have a rating for what wire gauges they're designed to work with, though there I go, nerding out about complex arcane specifications like "8-14 AWG" and such). You can probably cobble around it with more wire and connectors, but if you're not fixing the root problem, it's a rather cost-inefficient way of solving the issue (throwing wire wire at a connection termination problem).
In general a warm wire happens and I add more wire. In this case it's the connection, I added a second one in parallel.

What sort of "hell of a lot cheaper" prices are you seeing on it where you obtain the stuff? I know it used to be the case, but I just went poking around the site I usually order a lot of my wiring from, and 8AWG copper and 6AWG aluminum are almost the same price - 6AWG THHN-2 Al is $0.52/ft, 8AWG copper is $0.56/ft. I can't even find smaller aluminum wire anymore. Both of these are good for a 50A circuit under mostly standard conditions.
Probably jsut got lucky, I found a company selling Al wire (actually CCA) for a quarter of the price of anyone's Cu. They don't sell Cu.

It's marginally cheaper, and if it's a "run it once and be done" sort of situation, the differences don't really matter.
It's a bugger to fit. Doesn't bend into tight spaces, like inside outlets.

I tend to use the stranded stuff, though - as you note, it's a bit easier to work with. I don't mind working with solid wire, though. The house is wired up with 12AWG solid copper, and it's fine.
I find they can come out, or snap the connection on the back of the outlet if there's any movement, like pulling it out to fit another.

I'm pretty sure I used stranded for the solar runs. Solid is a bit easier to work with for some terminations, though.
I disagree, solid can miss the screw altogether, with stranded something will grab.

Then I have zero idea why you object to doing something like "looking up some wire ampacity charts and figuring out the proper wire gauge for your actual needs." Design it right from the start, and you don't have to go around "touching wire to see if it's too hot."
Time is a limited resource.

I was asking if your wire which you claim is 8A rated was rated assuming continuous or intermittent loads.
No idea, I was going by ampacity charts per gauge. It's only a rough estimate anyway as there are so many variables.

Heating is by definition a continuous load, for any hard wired heaters.
Nonsense. If you have a 5kW heater and only 2.5kW is needed to keep the room warm, it will cycle on/off at 50% duty cycle.

And also generally useless in designing anything more complicated than an extension cord. Wire gauge, insulation temperature rating, and the rest of the factors flow into some pretty simple charts and calculation factors based on what you want to do - if you've got more wires in a conduit carrying current, they're each derated somewhat because of total conduit heat dissipation issues, if they're being used in a high temperature environment, they derate as there's less overhead between ambient and the insulation rating temperature, etc.
All you need is "This is 20A wire. Deduct 20% if under insulation, deduct x% for this, y% for that."

You seem oddly resistant to the concept that electrical faults are a major cause of building fires that very much do kill people. Cracked insulation from lower than designed temperatures is a genuine hazard - and even if it doesn't arc, it's still allowing water and other things in to corrode sections of wire that are impossible to inspect, because they're in the center of segments of conduit, walls, etc.
What percentage of people die in a building fire? Probably a billion times less than a car accident or cancer. You sound like the UK government, concentrating on the wrong things.
3) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70798)
Posted 10 Apr 2024 by Mr. P Hucker
Post:
Won't they all go under 0C? People put wires outside all the time. My mother keeps her mower and extension cords in the garage and it gets to -10C there. They just go a bit stiffer.
Insulation not rated for the lower temperatures will likely get brittle. Norway and Finland often get -40C. When in the forces I saw insulation intended for warmer climes break. Some might be fine but just not been tested for lower temps but some not rated will almost certainly be dangerous.
Probably only applies to non-UK temperatures, and I'd imagine all cable sold in Norway would be ok. And it's hardly dangerous, someone might get a shock or a fuse might blow, not the end of the world. And for those with the nanny state earth leakage breakers, it's very difficult to get a shock.
4) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70797)
Posted 10 Apr 2024 by Mr. P Hucker
Post:
It's stranded, I'm not counting those, why would that matter, I just twisted them up hard and measured the total.
This single statement clearly demonstrates your total lack of understanding of cable construction. Twisting cables in the manner you describe does not totally remove the packing space between the cores so the actual CSA of the metal is always less than that which you've guessed at.
And yet it agrees with what's printed on the cable.

You are lazy, arrogant and stupid - clearly demonstrated by your disabling the "not wearing your seat belt" alarm when driving - don't forget it's an offence which costs you money when caught. Boasting about such acts does eventually end you up in court.
Since I've not had an accident since 1997 which would require a seatbelt, the chances of needing one are far less than the bother of wearing one. Why are you incapable of assessing risks sensibly instead of seeing every risk as the end of the world? And it's very easy to pull it across you when the bacon is coming. Even if that fails, it's only £100, which is worth it for the extra comfort of not being into BDSM for every journey.
5) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70794)
Posted 10 Apr 2024 by Mr. P Hucker
Post:
I hope you also undertook the oh-so-bring task of counting the number of cores as well. (It's not too bad when there are only 7 cores, but did I get to 37 or 39 before Fred shoved a cuppa under ones nose?)
It's stranded, I'm not counting those, why would that matter, I just twisted them up hard and measured the total.

All compliant (stranded) with current standards cable, above about 1mm^2, is required to have the conductor cross section, and insulation class (which may include the type of insulation), printed on the cable at regular intervals. Thus the cable you are suing does not comply with current regulations, or is rather old, and may, or may not, be compliant. There's a lot of non-complaint cable coming in from the far east (India & China being the main sources).
I either didn't look or it was a very short piece, I did say interconnects.

...and then there are "Arctic grade" cables, which extend the range down to -20C (ore even lower!), which is quite useful if you want to use the cable outside when normal people want to stay inside hugging the heaters....
Won't they all go under 0C? People put wires outside all the time. My mother keeps her mower and extension cords in the garage and it gets to -10C there. They just go a bit stiffer.

Most of us could reasonably claim to be short of money, but most of us do use the "right stuff".
Then you're not that short of money.

It's cheaper for good reasons - not the least of which being that without the appropriate markings it is automatically non-compliant with current standards.
I don't care for standards, which is why I voted brexit.

P.S. to horrify you even further I just snipped the wire on my new car coming out of the seatbelt socket. That foiled the health and softy system pretty easily. It thinks I have the belt on at all times. The bonging noise every 2 seconds for a few minutes is damn dangerous as it's very distracting while driving.
6) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70792)
Posted 10 Apr 2024 by Mr. P Hucker
Post:
What defines someone as a narcissist?
Overview. Narcissistic personality disorder is a mental health condition in which people have an unreasonably high sense of their own importance. They need and seek too much attention and want people to admire them. People with this disorder may lack the ability to understand or care about the feelings of others.
Who are you directing this at?
7) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70791)
Posted 10 Apr 2024 by Mr. P Hucker
Post:
GPU feeds, 12.6V, 4AWG ring. More the connections get hot.
The connections shouldn't be getting that hot - usually that indicates a poor crimp job, though if you're using aluminum wire (aluminium, however you want to spell it, same material - Al, of some reasonable alloy), you've likely got some oxidation issues going on at the connection. Oxidized copper conducts. Oxidized aluminum doesn't, and a high resistance connection makes for a lot of heat, and tends to make the oxidation issues worse until something stops working - or, more often than it ought, catches fire (I've seen research that the number of "thermally faulty" outlets in a fleet of houses with aluminum wiring vs copper is about 50x higher for aluminum - and that's before you get into the long term behavior of the wire, which is "less agreeable" in terms of work hardening, thermal hardening, etc).
Yeah it shouldn't and I don't know why, I just add more cable where there's a problem.

There are reasonable places to use aluminum wire, but I'd argue (as a serious DIY sort) that aluminum wiring is best left to people doing it professionally, because it really helps to have things like explosively welded lugs on the end of large gauge aluminum wiring (they literally weld the lugs to the wire with explosives, and there's no way for it to oxidize at the joint as the metals are firmly bonded). If you try to treat it like copper wire, you'll have a genuinely bad time of it eventually, because it's not well behaved like copper is - it work hardens more easily, it's more prone to stress fractures and cracks, and you pretty much can't use it in screw terminals for the long term, because the thermal expansion and oxidation behavior will eventually make your screw terminals glow with any serious power through them.
Some of us are short of money and make do. Al wire is a hell of a lot cheaper.

Or just use regular stranded cable and skip the fine stranded for interconnects. I've got a range of good crimping tools, to include a DC wire crimper that will do up through 0000AWG or maybe a bit larger.
I always use stranded, solid core is a bitch to work with. Not sure why anyone uses it really. It's like folk who buy straight screws instead of pozidrive.

Wiring up high loads with "cables laying around," where you don't know the wire gauge, haven't calculated loads, etc, is the sort of "casually sloppy with high power things" I'm criticizing you for
I checked the cross sectional area with callipers.

in the sense of claiming that you don't have enough electrical background to be able to have any interesting conversations about your shortcuts. At least in your posts here, you come across as having a "Eh, whatever, it works for now..." attitude towards wiring.
I have a degree involving electronics, I'm not stupid. And I can tell how hot it is by touching it, so I know if it will do.

Your wiring should (if it's halfway competent wiring) be labeled with wire gauge, either in AWG, or in cross sectional area, and it should also be labeled with the insulation temperature rating.
If I still had the reel.

The lowest temperature wiring insulation in common use is 60C/140F rated
That stuff shouldn't exist. At my last place of work, the librarian had a desk fan with the flex touching the central heating radiator. It melted. If it can't stand the temperature of hot water....

"Adding more when there's a problem" isn't a replacement for a properly designed system, as by the time you notice it's hot, you've likely already gotten things hot enough to start causing thermal damage and further oxidation.
Not if I check it regularly and don't allow it to be warm.

8A continuous, or intermittent?
It's heating, it depends on the weather it can be on for extended periods.

Typically, in electrical rating for wiring, there's a different rating for "continuous" (>3 hour) loads vs intermittent loads, and at least in the US National Electric Code, an 80% derating applies for continuous loads. So 90C 12AWG is rated for 30A, but for continuous loads, it's only suitable to 24A. This handles thermal mass and inertia in wiring - running a blender for 5 minutes is going to heat up wiring less than a heater, solar backfeed, EV charger, hot tub heater, etc.
Too much complicated stuff to look up, easier to use the suck it and see method used by programmers, which is why Boinc messes up all the time, and why Windows has updates every 5 minutes.

This is why wire also generally isn't rated for "amps"
It could be, they should rate it for amps with a note saying reduce by x% if under insulation, etc. Just like my extension reel says "13A except if not fully unwound, then 7.5 amps". Nice and simple to understand.

But at least there's an ocean between your place and mine.
You worry too much, take a pill.
8) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70784)
Posted 9 Apr 2024 by Mr. P Hucker
Post:
Ah, a BT engineer told me this was why my 1979 phone line was rubbish. He said something about them coming loose. But for the price I'll stick to aluminium!
See Terry Pratchett.

The reason that the rich were so rich, Vimes reasoned, was because they managed to spend less money,” wrote Pratchett. “Take boots, for example. He earned thirty-eight dollars a month plus allowances. A really good pair of leather boots cost fifty dollars. But an affordable pair of boots, which were sort of okay for a season or two and then leaked like hell when the cardboard gave out, cost about ten dollars. Those were the kind of boots Vimes always bought, and wore until the soles were so thin that he could tell where he was in Ankh-Morpork on a foggy night by the feel of the cobbles. But the thing was that good boots lasted for years and years. A man who could afford fifty dollars had a pair of boots that’d still be keeping his feet dry in ten years’ time, while a poor man who could only afford cheap boots would have spent a hundred dollars on boots in the same time and would still have wet feet.
Not necessarily true. Sometimes the cheaper thing is better value. It might cost 5 times as much for a better tool/battery/whatever which lasts twice as long. So just buy two of the cheap ones.

And in the case of aluminium wire coming loose, it only wastes two minutes of your time tightening it.
9) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70780)
Posted 9 Apr 2024 by Mr. P Hucker
Post:
Peter. Do some quick sums to check the rating of the cable needed for you 5kw resistive heaters. Even doubled "8A" cable is way under sized:
5000/240 = 20.83A (assuming you actually getting 240v in your location) - so you need to at least use three cables, single in air;
They're rated at 8A when in a 3 core sheath. Out of that sheath I expected them to handle 10A each. But what I think I'm coming up against is the trend nowadays for things not to do what they say on the tin. Disks are measured in billions of bytes, not real gigabytes. Cameras claiming 50MP only give you about a quarter of that, very easy to check. Paint which claims it needs one coat actually needs two.

but even that is marginal if the mains voltage droops to say 220v (which is still within spec of UK supply).
Actually resistive heating conducts less current as the voltage drops.

Interesting point, most people think it's been equalised with the EU, it hasn't, we're still 240 and they're still 220, which messes up some guitar amps. But most things are sold as 230V+/-10%.

Oxidation of conductors is more often associated with environmental conditions than temperature of conductor (unless the conductor is REALLY hot - over say 200C). The most common to fail first at elevated temperatures is the insulation. The mode of failure depends on the insulation material and the conductor metal will delaminate from the conductor, or go "brown and crispy", or go soft and floppy.
They weren't hot enough to melt the insulation, I've seen that in more extreme cases. They were comfortable to hold, but I could tell they were warmer than me. I'd guess 60-70C.

Evil screw connectors - aluminium (miss-spelled by those led by the Americans for spelling as aluminum) conductors take very badly to being compressed by most screw terminals rapidly becoming work-hardened and so fracture. (Yet another good reason for not using aluminium conductors in domestic installations.)
Ah, a BT engineer told me this was why my 1979 phone line was rubbish. He said something about them coming loose. But for the price I'll stick to aluminium!
10) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70777)
Posted 9 Apr 2024 by Mr. P Hucker
Post:
And I do use decent thicknesses of cable for high voltages too, so the wire doesn't wear out. They tend to oxidise if they're warm all the time, then they end up not conducting at all.
How "warm" are you running your wires if they're oxidizing on you? And are you running improperly terminated aluminum? Copper doesn't do that at any sort of sane temperatures (I typically use 90C rated wire, though occasionally have to derate for 60C rated breakers/switches/etc).

(in the land of "Doing it properly," I've yet to use aluminum wire for anything, and never intend to - the slight extra cost for copper is totally worth the tradeoffs of "Isn't evil in screw terminals" like aluminum is)
GPU feeds, 12.6V, 4AWG ring. More the connections get hot. Also 5kW resistive house heating, whatever cables I had left over to interconnect thermostats etc. 8A cable, but single cores exposed to air. I paired them up but they still get hot. A lot more than body temperature is call I can say.

I do have CCA for the GPUs, but it's sold as overthickness by the same amount that aluminium conducts less. That's aluminium, not aluminum, maybe it's different electrically. The wire was about a third of the price and should conduct the same. I didn't bother working out what to get, I just add more where there's a problem. Too complicated to calculate, depends where I clip on GPUs and PSUs.

Dunno what you mean by evil screw in terminals.
11) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70767)
Posted 8 Apr 2024 by Mr. P Hucker
Post:
Right. I'd forgotten your electrical knowledge was far enough off in the weeds that we can't actually have a reasonable discussion about what "shortcuts" are reasonable.
Nothing I posted suggests that.
12) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70764)
Posted 7 Apr 2024 by Mr. P Hucker
Post:
They are more important than you?
Yes. Absolutely. Without question. I'd rather not kill them to save a few dollars on doing a job properly, especially when I'm saving so much by doing the work myself.
You're missing an important point, the chances of it killing them. There's no 100% safe and 100% dangerous, you have to decide how much risk you take.

I don't find "doing it properly" to be a particularly painful process, either.
Properly often means a lot more expense and time.

In the context of electrical wiring, this means NEC wire gauge or larger (I discovered that past-self was clever enough to use the full rated wire gauge for a run from my charge controller to my batteries, even though I had a smaller breaker in place at the time, meaning that when I needed to upgrade the breaker to better match my increased production, I didn't have to replace the wire run), proper junction bars as needed, etc. And I have a thermal imager to find hot spots - it's quite the fun little toy that gets used often enough to verify things are running as expected.
If you're dealing with low voltages, it's voltage drops which count, not overheating. And I do use decent thicknesses of cable for high voltages too, so the wire doesn't wear out. They tend to oxidise if they're warm all the time, then they end up not conducting at all.

And we go overboard with safety. Obvious safety is common sense and doesn't need legislation.
The history of industrial accidents, aviation accidents, and quite a few other things disagrees.
You're going with media hype. You hear of 100 accidents and are appalled, but you don't think of how many people didn't have the accident. It's the percentage which counts. Clearly 10 people dying out of 100 is not the same as 10 people dying out of a million.

Quite a few things that matter to "not kill people" are not, in fact, "common sense" - or they'd have been done.
No, it's just people taking risks. It's obvious what's dangerous and how dangerous it is.

Further, there's a difference (to my mind, at least...) between "doing something stupid that kills yourself" and "doing something stupid that kills other people."
Why? Why would you class yourself as less important than others?

How pathetic. I use two hands and it won't kick right up to my face. If it did, it would cut out before it got that far. And kicking up is damn obvious for anyone who understands the most basic law of physics, equal and opposite reactions. If you don't understand it, I don't want you to live. Imagine a world where all the stupid folk had been killed off.
Man, you're an ass at times. I assume you do that on purpose. But it's far from the first time I've encountered that mentality.
You like living in a world of idiots?

I typically wear a helmet and hearing protection
You must have sensitive ears. My mother does too, I was drilling through some tiles in her bathroom to put up a rail, and she actually said she felt dizzy from the noise. It didn't bother me at all, yet I have perfect hearing and she doesn't.

when using a chainsaw, and as I have a perfectly good set of chainsaw chaps, I wear those often enough too. I know people who've gone through 6-8 months of rather extensive pain, suffering, and loss of employment from having a circular saw go through their leg on the job.
And how many people do you know who have never had that happen?

It's the same reason I wear competent motorcycle gear when riding.
That I would do, because I think the chances of coming off are very high. So high in fact I'd never ride one. Motorcycling is probably more dangerous than using your saw without a helmet. In fact you admitted you've had an accident on one.

Don't get me wrong. I fully support your right to use a chainsaw with zero protection at all. I fully support people riding motorcycles in shorts, a t-shirt, and flip flops. I just happen to think quite a few things like that are stupid. And I support my right to call people out for their overt stupidity.
And I support their right to do it so they can be removed from the gene pool.
13) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70755)
Posted 6 Apr 2024 by Mr. P Hucker
Post:
I mean seriously, warnings on chainsaws not to stop them with your genitals?!
Where do you buy your chainsaws from? Neither of mine came with any such warnings!
https://www.forbes.com/2011/02/23/dumbest-warning-labels-entrepreneurs-sales-marketing-warning-labels_slide.html

And health and safety measures are only common sense for someone who fully understands what is involved. A chainsaw for example can under certain circumstances kick up which is why I always wear a safety helmet while using mine
How pathetic. I use two hands and it won't kick right up to my face. If it did, it would cut out before it got that far. And kicking up is damn obvious for anyone who understands the most basic law of physics, equal and opposite reactions. If you don't understand it, I don't want you to live. Imagine a world where all the stupid folk had been killed off.
14) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70751)
Posted 5 Apr 2024 by Mr. P Hucker
Post:
Never understood why people need to be warm to take a bath. Cold temperatures are actually very good for your health.
I've no problem with it personally. I'll not fault my wife for raising the temperature up a bit with a 1 or 2 year old for bath time.
Age is irrelevant. Some people bathe their babies in cold water to boost their health.

As for safety, that's for girls.
Uh... okay. Cool. I'll try not to burn down the house with my wife and kids in it, for the girls in it.
They are more important than you?

And we go overboard with safety. Obvious safety is common sense and doesn't need legislation. I mean seriously, warnings on chainsaws not to stop them with your genitals?!

Complete. 12.8V 280Ah for about £500. Surprisingly large and heavy, similar to lead acid! I thought LiFePO4 was smaller and lighter?
It's smaller and lighter, especially if you're looking at derating for temperature and such. Just not as much as most people assume.
I was going by the numbers on the side before any deratings for DOD etc, same V and Ah I thought ended up about half the size and half the weight. I measured it once for electric cars.

The 12.8V/400Ah EG4-LL is just under 100 pounds. The Trojan SPRE 06-415s are a similar rated capacity (somewhat less in practice, but they're broadly close), and a pair of them to make a 12V system would be 236 pounds. So, slightly more than twice as much for a similar capability.
Sounds similar weight per Ah to mine. The delivery driver was moaning they gave him a bad back. I showed him no sympathy, especially when he kicked someone's Dyson box out of the way to get to them in the van. Maybe I should look back through camera footage and show it to his boss?
15) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70735)
Posted 4 Apr 2024 by Mr. P Hucker
Post:
My wife raising the temperature some Tuesday afternoon because one of our kids is taking a bath doesn't mean that the temperature needs to go up every Tuesday afternoon from there on out.
Never understood why people need to be warm to take a bath. Cold temperatures are actually very good for your health.

We've gone over this before, and I find nothing interesting about re-litigating it. You prefer to ignore the rules and build as cheaply as possible, my social group and I prefer to build better-quality-than-professionals sort of stuff for radically less money than it pays to get someone to slap it together. It's not hard to do it right, not significantly more expensive in materials, and it tends to both perform better long term and avoid some of the more energetic failure modes that seem to get YouTube views.
In that case, yes, you have to use their equipment, but that raises the price so much it ain't worth it. I do it my way with my batteries and they don't get my power.

As for safety, that's for girls.

Bare cells, or complete packs with BMS?
Complete. 12.8V 280Ah for about £500. Surprisingly large and heavy, similar to lead acid! I thought LiFePO4 was smaller and lighter?

If you're power limited, underclocking/undervolting (or just reducing the power limits, which gets you the same thing on any modern bit of silicon) will improve compute per joule substantially.
I'll probably look into that once they're up and running on solar. At the moment I don't care about power usage.
16) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70730)
Posted 3 Apr 2024 by Mr. P Hucker
Post:
I can think of half a dozen ways to do it. But I'm a programmer, and I operate in the Linux ecosystem.
Know where I could find Windows instructions/people?

The house system is 15.9kW of panel, though optimized for "long solar day" production vs "peak kWh per panel kW," given what I expected to happen with net metering agreements out here.
In the UK, they pay you about a seventh of the money to sell them power as you buy it for. So not worth doing. Best to store it in batteries and screw them.

For a DIY, code compliant
So much cheaper to ignore rules.

ground mound, grid tie solar install around here, $1/W is doable (I know someone who's done that), but batteries are just expensive.
Not so bad now, I can get LiFePO4 for just under £2/Ah at 12.8V. They claim 6000+ cycles to full depth of discharge (some companies say don't do that, but this one says just not to leave it under 5% charged for an extended period).

That adds a LOT of power consumption for only marginally additional compute power. I'd be surprised if you got more than about 10-15% extra compute from the 50% bump in power limit. If you're power limited, go the other way. I run my 2080 (240W nominal power limit) at 125W quite a bit of the time, and it definitely isn't halving compute power.
I was going by MSI Afterburner graphs. It was throttling the clock when there was not enough power. The amount of power added appeared to be similar (I didn't do any precise calculations) to the extra clock speed - remember I was changing a limit, not constant usage. The power used doesn't change at all unless it's throttling.
17) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70726)
Posted 3 Apr 2024 by Mr. P Hucker
Post:
Yup. I poke the "suspend time" a couple times throughout the year, will manually change things as needed, but I've avoided too much automation on it. I just don't find automation helpful for a lot of this stuff, and I've seen it go badly wrong more than a few times. It's not a production system, it's a hobby system, but "the rest of my office" is a production system (I work from here), so I err on the side of battery state of charge when needed.
If only I could simply have the computers suspend (or just pause Boinc) when battery voltage is under x. Sounds like a very simple thing, but unless you're a programmer, impossible.

But I'm seriously overpaneled out here, so can make up a lot of it on "Well, I screwed that up, but 5kW of panels solves a lot."
Do you mean 5kW peak? That's not very much. The standard for a UK house is 16 250W panels. I've got 12 410W panels, so same as you if you meant peak. But then I think you're in a sunnier place.

... but that was 3 grand (UK money) of panels and batteries
I haven't totaled up my system... it's certainly far more,
If it's only 5kW peak it shouldn't be far more. But then you bought it a while ago and prices are plummeting.

but I also have a system suited to a small house
Most small houses don't run many computers, which use a lot if they're on 24/7.

The same goes for GPUs - you can lower the power use on them, and substantially increase compute-per-joule.
The only setting I have on my ones is "power limit". I guess that would do the job, I've never tried putting it under the standard "0%". I only raise it to max (usually +20% or +50%). The +50% one then immediately melted the power connector, so I had to solder the wires on.
18) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70722)
Posted 3 Apr 2024 by Mr. P Hucker
Post:
But you can have a sunny week or a rainy week, where presumably you adjust something. Do you get computers to run for half the day? Or reduce the cores used?
If it's a sunny week, there's nothing to adjust. The computers just run. If it's particularly hot, I may let them sleep overnight to avoid cooling loads, though I'm planning to move some hardware into a box outside with filtered vent fans this year to help reduce the summer cooling demand.
Ah, so pretty much manual then, I'll stick to that too.

If it's rainy, I'll only run one computer at a time, or let them sleep, though I try to avoid grabbing too many short-lived tasks if I know the weather is going to be cloudy in the next week or so - I just set my machines to not grab new tasks, drain them out, and wait until I have more power.
You must live in an alternate reality where weather forecasting is remotely correct.

I'll just keep an eye on battery level and tweak something. At the moment I'm predicting 250W continuous in winter and 1250W continuous in summer, which isn't much, but that was 3 grand (UK money) of panels and batteries, I don't want to hurry to spend that again!

I'll probably start buying some newer more efficient CPU/GPUs instead of more solar.
19) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70707)
Posted 3 Apr 2024 by Mr. P Hucker
Post:
Solar and Boinc is no good for long tasks. Solar requires variation of the computer power.
I don't try to match instant power demand to solar production...........But there's also another thread, specifically related to off-grid solar, better suited to informing me how what I'm doing can't possibly be working.
I've posted on the end of here: https://www.cpdn.org/forum_thread.php?id=9208&postid=70706#70706
20) Message boards : Cafe CPDN : Off-Grid Solar/Renewable Energy Discussion (Message 70706)
Posted 3 Apr 2024 by Mr. P Hucker
Post:
I'll assume this is the thread you pointed to from the new tasks thread.

Like you I plan to use batteries to even the load and not switch computers off day to night. But you can have a sunny week or a rainy week, where presumably you adjust something. Do you get computers to run for half the day? Or reduce the cores used? Reducing the number of computers running causes tasks to not get done for a week, which is no good.

I'm on windows and I'm not sure this can be automated at all.

What I'd really like is a way to tell windows "you're on battery", which will suspend Boinc, or even the computer (although the computer would require manual turning back on if I went that far).

The only way I can see to do this is to make the computer think it has a UPS and it's switched to battery, when what's really happened is the solar batteries have dipped below a certain voltage. I can do basic electronics but not much. Not sure how to interface that to perhaps a salvaged bit of electronics from an old UPS to give it the USB signal.


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