MikeSharp01

One thing I have noticed, although I guess I could have worked out it was there, is the amount of power the inverter (ours is hybrid so ready for a battery) draws. I have not done the long term math yet but if feels like about 5-7% so for example at 6kW of generation the Inverter is using around 350W. I am somewhat with @nod - the numbers on the battery just don't add up but if I take the 'save the planet' line I can square the circle so if there is any money left at the end of the build we will get a couple of batteries.

How do you keep the data loggers running - batteries?

Yes we exported 26kWh today, frustrating waiting for the export MPAN number to come through after we commissioned the PV 3 weeks ago, then we can get our 15p per kWh!

Get yourself a BMW era Mini Cooper S, like driving a roller skate - fast enough to be fun, especially in 'SPORT' mode, looks great when clean, mostly comfortable - give run flat tyres a miss, and mine has 200K miles now - still smiling.

So are there two branches off the MVHR and are there two heat batteries, the things the water flows through and the air passes over on on its way to the rooms - one on each branch? The counter flow heat exchanger deals with the heat recovery bit of the job. If there is only one branch / heat battery then the problem must be a flow rate / balancing issue because the difference cannot be explained any other way I can see and even then its a long shot so something odd at the very least.

Good to see progress, keep on keeping on.

No I agree, mine runs on a PI 5. Yes we are using a hive cloud mainly because I have access via work but I can encrypt anything I want. My goal in using the phone is to show people how simple it can be but it has all the down sides of every other system of systems on the planet. They do, but that doesn't stop them being complex in all other respects and most people don't know what those respects are.

Not 100% sure, because there might be much more complex things coming, but I think the average modern car is a phemominally complex system of systems and some people others may define as 'right plonkers' seem to manage them in getting from A-B mostly without incident. So it looks like you can make extremely sophisticated systems work for the general humanity you find about the place - perhaps this should be our aim.

What if the house is autonomous - IE runs itself? Then the human interface can be a normal on/off switch for the heating, MVHR, lighting etc. (naturally with a parallel app interface to allow on/off from anywhere on or off the planet.)

Provided your sensors are sending MQTT messages you don't need Node Red on a PC to subscribe. The little app I feature above just needs you to enter the broker details and build simple tile based dashboard on your phone each tile can subscribe to one or more topics. So my graph subscribes to 3 topics and stores 1000 readings.- All free and no PC needed..

Welcome to THE forum for people like us.

One might ask why does nothing ever get better for customers

Yes Gus, for me it is fun, and I use aspects of it in the part time day job. Here is my latest Gizmo - an RPi Pico with a DHT22 temperature and humidity sensor attached. I have several of these around the place. This one also gathers information from the local weather station (local Temperature), gets readings from the other units (House Temperature) and interrogates the PV inverter before sending a bunch of MQTT messages to my hive cloud based broker from which I subscribe using my phone to get a great little dashboard. The MQTT dashboard app is a very lovely piece of work. See below for details. I may write all his up at some point. I won't I've using them to control anything but just to gather data I can use to set up the controls when I finally choose a system - probably home assistant. App is:

No so easy with Arable crops though!

If you are going to do this with conduit you are best advised to put in a draw string. I have used plastic builders brick line, it is amazingly strong, does not stretch, wont rot and is very thin here and have only had one issue where I was trying to pull 2x 10mm2 cables through 20mm conduit. As you pull a cable through with it you can pull in more string and it makes it so easy as does a bit of cable lube.

All sounds like a candidate for a Model Based Systems Engineering (MBSE) with simulation (simulink or some such) approach. You have many knowns, you can build assumption ranges for the rest and play away to your hearts content.

Agree it is not tat - but then I suppose from the point of view of those who like to fill their homes with consumer tat neither is theirs's, it gives them meaning, status, satisfaction, a warm glow inside, pride and perhaps a sense of personal aggrandisement. One persons tat is another's nugget of gold. I will get my coat.......

Just seeing it from other world views - for me the trick with everything you get presented with is to see it from other perspectives, perverse as I can be I like to be able to hold two opposing ideas in my head at the same time and see how things pan out from there. So I might agree a V8 is a lovely thing, but a V16 or a V24 might be seen as better and perhaps equally practical, so anyone who can afford to fit such an engine is such a vehicle would see a V8 as pointless tat. Alternatively you can take an environmental stance or any one of many others.

How do they manage the switch over and back again when the AC mains returns is it automatic?

Says he who has what many would see as a load of relatively pointless tat in his profile picture!

Feels like a question an LLM could answer so I poked mine, chatGPT, and here is what I got. When additional electrical work is added to a current EICR, the EICR renewal date typically does not stay the same, but rather runs from the date of the additional work, as a new EICR should be issued to reflect the updated condition of the installation. Here's a more detailed explanation: EICR Validity: An EICR is typically valid for 5 years from the date of the inspection. Remedial Work: If an EICR identifies issues that require remedial work, a new EICR should be issued after the work is completed to confirm the electrical system is safe and compliant. New Work: Similarly, if new electrical work is added, a new EICR should be issued to reflect the updated condition of the installation. Renewal Date: The renewal date of the EICR would then be based on the date of the new EICR, not the original one. Example If you have an EICR that is valid until March 2027, and you have some electrical work done in May 2025, you should get a new EICR after the work is done and the new EICR will be valid for 5 years from May 2025, not March 2027. I wonder if this is a slippery slope to allowing the machines to rule the world or a useful tool for the curious or both.

I am going to start a campaign to sort the basic insult that has become embodied in KISS (Keep It Simple, Stupid) - the comma is important. It was envisaged as not being an insult when Kelly Johnson a lead designer at Lockheed Martin in the 1960s first coined it, more of a note to self and to stress simplicity. Sadly it is often not used like that these days so I tend to use it now with a slight rearrangement to KISS (Keep It Stupidly Simple) which, for me, makes it less insulting when people use it talking to others. Rant over.....

That is useful stuff, I will need another glass of wine to get my head around this little lot. Thanks for putting it together.

I suspect it was the very dry way it was taught, I had done the basic stuff at A level but at Uni it had no applications shown to us unlike the software stuff, mechanical design, electronics & systems all of which seemed to be going places - or so it turned out. I was also somewhat put off by materials science but the good bit of that was, believe it or not, the wood bit - our lecturer had a thing about it.

Thanks Nick - sorry that pic was from 2017, I thought if it has been shovelling stuff up hill since then life must be fun somewhere!