I thought building regulations were only for selling a house.

As Rob says any building works have to satisfy the building regulations.

Yeah, like you have to obey the speed limit.

We put a loft extension in a few years back and to satisfy the building regs,

Internal work is not notifiable.

had to have linked smoke detectors on all three floors.

In Scotland all existing homes have to have this. I don't know anyone who actually did it.

We also had to put rock wool in for sound insulation under the floor boards of the extension, the logic being apparently that our walking about up there could cause problems for our neighbours sleeping on the floor below.

Your loft is above another house?!

Depends. I know Scottish law is different in a great many things but in England, extensions need planning permission if they increase the floor area of the property above a certain percentage.

I thought the whole of the UK was the same, 8 metres back from the house if you're detached, 6m if you're not. (The 8 and 6 might be slightly different numbers, they're about that).

I was not completely accurate with regards to right to light. There is a right to light in your property and a development can be stopped or reduced in size if it affects the light to your property but you have to have enjoyed that light for 20 years before it applies.

What an absurdly long time. They have so many petty pointless rules, then the one thing which is important they ignore.

That act applies only to England and Wales. Not sure what the position North of the border is.

It's not applicable, we don't have sunlight up here.

The Scottish government publishes the rules, which are clear as to what does and doesn't need planning permission.

Nothing written by the government is in any way clear.

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?).

It's easier to seek forgiveness than permission.

have a chat with the planning people for clarification

That is certainly the route I would go down. They were very helpful with us. Also worth chatting with the building regs people and getting them involved at an early stage. That was helpful for us.

But once you ask them, they know what you're thinking of doing, then you can't do what they said no to or they'd notice. Best to do it without anyone knowing. As long as you don't annoy a neighbour, who's going to complain? Council inspectors don't have a beat like policemen.

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).

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.

Do you mean that idea to have roads as solar panels? Why didn't that work out? Too much physical wear? Too much dirt?

Yeah, it was some crowdfunded thing from 8-10 years ago, hex tiles that have solar panels, lights, snow melters, etc, that you were supposed to build roads out of. They're staggeringly expensive, fairly awful at being a road in terms of traction, unreliable in practice, etc. And every now and then, you see some gouges in a road out here from a trailer that's come off the hitch for some reason, or failed suspension springs or whatever. You get a quarter mile of gouge in the road and they fill it in next time they resurface it. Do that on solar tiles, and you've done millions of dollars of damage. It's just a solution in search of a problem - asphalt is really good at being road, solar panels are really good at laying around in the sun protected from abuse, and trying to merge the two just leads to a very, very expensive solution that's no good as a road and no good as solar panels. It's like flying cars. They've existed for almost as long as airplanes have existed, and you can't solve the problem that a flying car is an awful airplane and an awful car, for more money that a few nice instances of both types of vehicles.

So make the switch correspondingly bigger.

Ok. So now it's a lot more expensive. It's not that you can't do it, it's that it almost never makes any sense.

What voltage are LiFePO4 batteries at with various stages of charging, discharging, charge level?

A 4S bank of LFP is pretty much the same as automotive lead acid. You could operate it around 12.8V without too much trouble in the flat of the charge/voltage curve. Though it'll be higher when charging. You'd be better off with a higher voltage bank and buck converters.

=======

Please stop talking about "12V" solar panels. The panels should have a short circuit current, open circuit voltage, and maximum power point current/voltage on them. Or, at a minimum, refer to them by cell count - a "12V" panel is typically 30 cell, a typical house panel is 60 cell, larger house panels are 72 cell, and there are some larger ones out there for big ground mount installs. But even within those, there's a lot of variance depending on the details of the cells used.

I've only heard of 12/24/36/48V arrays, but the peak is higher.

My 48V office bank is running with four 60 cell house panels in series, and is currently 127V into the charge controller. My house array is 12x 60 cell in series, and is currently about 340V into the inverters (depending on the string).

You use a charge controller to buck this down to match your battery voltage, to do the maximum power point tracking, etc. So I have, again, using my office system, 14.7A coming in off the panels and 29.7A going into the battery terminals (most of which is coming right back out to run loads).

There are some exemptions in the NEC for 48V nominal and below, so that's why you rarely see higher voltage storage banks - it changes the regulatory requirements, for those as care to bother with them.

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).

They don't do uncivilised things like that here, why would they? If nobody complains about something, it's not affecting anyone, so there's no need to take action. Or are they trying to make money for themselves? It's not like it's a criminal offence. It costs far less to do things without telling them (10 times cheaper than my neighbour in my case), so it's worth taking a tiny risk some pratt of a neighbour complains.

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.

I know a woman who did a loft conversion to her upper flat (with dormer windows, and a door to access it from the roof access level at the top of the main stairs). She never thought she would need permission, as it's her own property!! Many years later, somehow they got wind of it and said "since nobody has objected in x years, just leave it". If she had applied for permission, she would have been refused, they said as much. So it was well worth her while doing it.

Do that on solar tiles, and you've done millions of dollars of damage. It's just a solution in search of a problem

I accept it's not economical, but it's not "a solution in search of a problem". The problem was finding loads of land to use for solar panels. And what better than land already used for another purpose? Like wind farms in a sheep field.

So make the switch correspondingly bigger.

Ok. So now it's a lot more expensive. It's not that you can't do it, it's that it almost never makes any sense.

Switches have to be the cheapest part of the electricity system. Just how much bigger a gap are we talking?

A 4S bank of LFP is pretty much the same as automotive lead acid. You could operate it around 12.8V without too much trouble in the flat of the charge/voltage curve. Though it'll be higher when charging. You'd be better off with a higher voltage bank and buck converters.

Looking at some curves, it looks like 12.8V in use, 13.6V when charging. So I could have high voltage panels buck converted to any battery voltage, then any battery voltage buck converted to 12.6V for the GPUs. So the battery voltage seems immaterial?

Please stop talking about "12V" solar panels. The panels should have a short circuit current, open circuit voltage, and maximum power point current/voltage on them. Or, at a minimum, refer to them by cell count - a "12V" panel is typically 30 cell, a typical house panel is 60 cell, larger house panels are 72 cell, and there are some larger ones out there for big ground mount installs. But even within those, there's a lot of variance depending on the details of the cells used.

They're called 12V panels because you use one to charge a 12V battery. People are not going to go into a shop and ask for a 9 to 18 volt panel!

My 48V office bank is running with four 60 cell house panels in series, and is currently 127V into the charge controller.

That's 31.75V per panel. So 24V panels? I've never known a 12V panel go that high.

There are some exemptions in the NEC for 48V nominal and below, so that's why you rarely see higher voltage storage banks - it changes the regulatory requirements, for those as care to bother with them.

Why would there be a requirement for your battery voltage? What matters is what goes out of your system.

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.

And if the property owner doesn't pay, then what, take the house? The government are a bunch of outlaws and we need to get rid of them. Read up about some off grid living. We should all do it and escape from their evil clutches. Adults telling other adults what they can't do? What on earth?!

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).

So in the case you mention, nothing actually collapsed, the council just said it might. And instead of repairing it, they demolished things. Typical moronic attitude.

You need to understand the difference between damaging other people's property and damaging your own. If you only harm or cost yourself money, who cares?

A prime example is insulation, which is only affecting your heating bill and not endangering anyone including yourself.

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

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

I know what I'm talking about, and they could have just shored it up with underpinning. Don't use capitals, it indicates you've lost your temper and all valid reasoning. And you don't get to decide when the conversation ends.

I accept it's not economical, but it's not "a solution in search of a problem". The problem was finding loads of land to use for solar panels. And what better than land already used for another purpose? Like wind farms in a sheep field.

When you've invented a "solution" that:
(a) Costs more than a road and solar panels separately,
(b) Is worse at being a road than road and solar panels separately,
(c) Is worse at being solar panels than a road and solar panels separately,
(d) Turns minor asphalt damage into "literally millions of dollars of equipment destroyed,"
(e) Doesn't actually work in the demonstration deployments,
I have a hard time calling it a "solution" to anything of interest. Outside getting a couple million in crowd funded retirement. It did that very well.

Looking at some curves, it looks like 12.8V in use, 13.6V when charging. So I could have high voltage panels buck converted to any battery voltage, then any battery voltage buck converted to 12.6V for the GPUs. So the battery voltage seems immaterial?

That's what I do. And because 48V to 12V converters that handle any serious power are quite expensive, I accept the losses of going to 120VAC first and use the cheap 120VAC to 12VDC converters commonly known as "PC Power Supplies."

They're called 12V panels because you use one to charge a 12V battery. People are not going to go into a shop and ask for a 9 to 18 volt panel!

You could call them 30 cell panels. Or you could use a MPPT charge controller instead of a straight through PWM one and avoid the entire problem.

That's 31.75V per panel. So 24V panels? I've never known a 12V panel go that high.

Yeah. They're 60 cell house panels.

Why would there be a requirement for your battery voltage? What matters is what goes out of your system.

Because 400VDC battery banks are properly hazardous in a variety of interesting ways, as occasionally shown when UPS battery rooms in datacenters blow up.

Forget it. You don't seem to believe that any regulation you don't personally "think makes sense" exists for any reason whatsoever, and therefore can be ignored at will. You're welcome to do that, and I'm fairly glad you live a decent distance away from me. I'm annoyed at some of NEC (the National Electric Code in the US), but there are decent reasons for most of it, mostly written in blood (a result of failures leading to deaths).

When you've invented a "solution" that:
(a) Costs more than a road and solar panels separately,
(b) Is worse at being a road than road and solar panels separately,
(c) Is worse at being solar panels than a road and solar panels separately,
(d) Turns minor asphalt damage into "literally millions of dollars of equipment destroyed,"
(e) Doesn't actually work in the demonstration deployments,
I have a hard time calling it a "solution" to anything of interest. Outside getting a couple million in crowd funded retirement. It did that very well.

It's a failed solution, but still a solution. Your phrase is more suited to things nobody actually wants, like half the Windows interface. The solar roads was a good idea, and could have been good. You don't know until you try.

That's what I do. And because 48V to 12V converters that handle any serious power are quite expensive,

Can't you just use solar charge controllers? They're dirt cheap.

I accept the losses of going to 120VAC first

We use a more manly 240V here. More efficient power supplies, thinner cables, no messing about with another wire in your house for the split phase.

and use the cheap 120VAC to 12VDC converters commonly known as "PC Power Supplies."

2nd hand server ones are best. HP Blade server supply, 2600W, 12V only, £14.

You could call them 30 cell panels.

Who says everyone uses the same number and type of cells?

Or you could use a MPPT charge controller instead of a straight through PWM one and avoid the entire problem.

What problem?

Yeah. They're 60 cell house panels.

Last time I used those they were 12V, maybe they were wired in series parallel inside. They gave out 9-18V IIRC, about half yours.

Because 400VDC battery banks are properly hazardous in a variety of interesting ways, as occasionally shown when UPS battery rooms in datacenters blow up.

There's no reason a larger number in series instead of parallel would be more likely to blow up.

Forget it. You don't seem to believe that any regulation you don't personally "think makes sense" exists for any reason whatsoever, and therefore can be ignored at will.

And you trust morons in power to have some common sense. There are countless rules which 99% of the population thinks are stupid, and only the OCD follow.

You're welcome to do that, and I'm fairly glad you live a decent distance away from me. I'm annoyed at some of NEC (the National Electric Code in the US), but there are decent reasons for most of it, mostly written in blood (a result of failures leading to deaths).

Shit happens, but it's quite unlikely. Live a little, save a lot.

Last time I used those they were 12V, maybe they were wired in series parallel inside. They gave out 9-18V IIRC, about half yours.

I give up. I've no idea at all what sort of weird nonsense your side of the pond uses for solar panels then.

You apparently have 57.3 cell panels wired Wonkaways or something.

The panels I've dealt with out here, outside "toy" size panels, are 30 cell panels that are suited for PWM charging of 12V lead acid batteries if you don't care about efficiency, 60 cell house panels, 72 cell industrial panels, and they're all wired in series. The only series/parallel stuff I've seen are the half cell panels, which are 144 cell panels wired with the top and bottom as 72 cell series, and they handle partial shading better than the full cell stuff, with, theoretically, slightly less resistive losses in the panel internal wiring (or less wire based shading because you can use a smaller interconnect wire). But they're still electrically identical to a standard 72 cell panel once you get outside them.

There's no reason a larger number in series instead of parallel would be more likely to blow up.

Arc fault issues, and the challenges of handling that many cells in series and detecting some of them being weak.

Since you'll always do everything perfectly by your own standards, do whatever you want and I'm sure you'll never have a problem.

And you trust morons in power to have some common sense. There are countless rules which 99% of the population thinks are stupid, and only the OCD follow.

It costs me very little more to do things to the commonly accepted spec, and I'd far rather have done that than explain to an insurance adjuster why something I did my way was really fine, despite having burned down the house from some electrical fault. Yeah. I sometimes run a larger neutral than makes any sense (my inverters require a full size neutral, despite not using it for more than a fraction of an amp), and I design stuff so it's a minimal amount of additional wire. Doesn't really get me that upset, because I've also seen how often things get repurposed later for other uses where that sort of thing is handy to have around.

Shit happens, but it's quite unlikely. Live a little, save a lot.

And I'd prefer that if shit happens, I can explain (with documentation) to the insurance agent that, yeah, I did wire this particular thing to NEC spec, and had the local electrical inspector sign off that it was done properly and to code, in a workmanlike manner. It's a lot easier if I can point to the permits on file for having done exactly that.

If you want to YouTube grade hack crap together, more power to you. I'm just glad you're not doing that on my hill.

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 ;-)

I give up. I've no idea at all what sort of weird nonsense your side of the pond uses for solar panels then.
You apparently have 57.3 cell panels wired Wonkaways or something.

These, 60 cells judging by the number of squares: https://www.ebay.co.uk/itm/374812623009 Those are 24V, but I had some 12V ones, so they must have been series parallel. No idea where you're getting 57.3 from. Whatever I had (presumably a dual 30 cell) was rated 12V and gave out about 9-18V depending how bright the day was. Maybe it would go higher on the equator.

Arc fault issues

Unlikely.

and the challenges of handling that many cells in series and detecting some of them being weak.

Equalisers are cheap and easy, just use more of them.

Since you'll always do everything perfectly by your own standards, do whatever you want and I'm sure you'll never have a problem.

My level of standard is "it works". Not "it's safe".

It costs me very little more to do things to the commonly accepted spec,

Completely untrue. There are so many petty rules you end up with stuff you really don't need.

and I'd far rather have done that than explain to an insurance adjuster why something I did my way was really fine, despite having burned down the house from some electrical fault.

I don't have insurance, insurance is a scam, you pay money even if it doesn't happen.

Yeah. I sometimes run a larger neutral than makes any sense (my inverters require a full size neutral, despite not using it for more than a fraction of an amp),

How do they "require" it? Will they refuse to start up without one? I assume you mean you're only using 240V appliances, so the neutral doesn't even need to be there, and how would it know?

So much easier without your dual voltage nonsense.

And I'd prefer that if shit happens, I can explain (with documentation) to the insurance agent that, yeah, I did wire this particular thing to NEC spec, and had the local electrical inspector sign off that it was done properly and to code, in a workmanlike manner. It's a lot easier if I can point to the permits on file for having done exactly that.

Why do you worry about the unlikely?

I've upgraded my office power storage system to a set of EG4-LL lithium iron phosphate batteries - so I have about 15kWh of storage inside my office shell now (3x batteries, they're each a 4U chassis, assembled into a rack case with busbars).

This should let me run light loads overnight, almost all year round now. The lead bank wasn't up for overnight compute for the most part, but with the rather substantially more usable energy storage here, and them being in my office enclosure, it should improve my compute usefully! Once we have more compute to do...