Dillsue

That's a 3 phase HV supply so you've got a 3 phase transformer....you can see the 3 isolation switches on the pole below the transformer. Shouldn't be crazy expensive to give you a 3 phase supply if you wanted, but.. With the electrification of the country there's going to be lots of distribution upgrades required and if the transformers been there a while it may not be up to supplying 4 houses with EVs, HPs etc. . If that's the case your DNO may upgrade it for free and give you a 100A supply. When we asked to double our PV export our DNO found our transformer wasn't adequate for a modern supply and replaced it free of charge together with refurbishment of all the poles and cabling around us. If you initiate an enquiry and request a supply upgrade/ PV export you may find the same principle applies, particularly if the transformer is old and rated for electric demand from decades ago. If any of your neighbours are planning increasing demand then share that with your DNO

There's no harm in asking for costs to upgrade either to 3 phase or 100A single phase, if that would work. Has your transformer got 3 phase coming to it? Ours only has 2 phases at 11kv so if we wanted 3 phase there'd be quite a bit of work adding the third phase Maybe worth checking that all the wiring from each consumer unit is separate from the other if you're going to put them on separate phases......you don't want any connections with 400volt in the house!

You mention some modifications since install such as- changing TRVs, shutting off radiators, adding glycol, legionella timer. Has the system worked reliably since any or all of these were done? You also mention changing parameters but I wouldn't tinker with anything until you get the system working again as installed. By all means tinker and fine tune once it's up and running again, but not until its working for the winter.

Some options might be- Speak to the cylinder manufacturer and ask them about recovery/reheat times at various flow temperatures Turn the pellet flow temp down to 50degrees, if possible, and test the reheat time Temporarily fit a blending valve on the flow to the cylinder and test a various flow temps. Bit of work but may save your existing cylinder

Min power needed for heating seems to be around 1000w so unlikely to be powered from 2.5kw of PV during the heating season??

I'm fairly sure a Tesla PowerWall is AC coupled and is connected at 240VAC? Within the "battery package" is an inverter/charger that takes in AC to charge the batteries and supplies AC to power loads. If you want to connect a PW at DC you'd likely need to open the casing and bypass the inverter/charger which would void your warranty. You'd also need a DC charge controller to regulate the charge from the PV. Plenty of DC battery packs available but don't think a PW is what you're after A 2.5kw array is gonna supply next to nothing in the winter when going to need the ASHP the most. Have a look at PVGIS to see what you'll get.

Having a joint in the cable is no weaker than any other connection in your electrics of which there are many. It's not perfect but perfectly acceptable

No idea if it's related but setapp was updating itself yesterday and maybe the monitoring app was updated? Wouldn't be the first time an update has been cocked up. Just guessing, but maybe there's a way of rolling back the app to an earlier version, if it was updated

We're at the end of a 1/2 mile long 11kv supply with a dozen or so properties including a couple of farms but I've no idea if that means we got export consent automatically. You can build as big a system as you want if you implement export limitation. That way you can use all the power your system generates but your inverter will throttle its output to limit export to whatever your DNO allows, if you're not using the power

Be interesting to know where those installing renewables are going to get their ROI if this becomes the case

I've just connected to the monitoring site without any problem. Maybe try and use the website rather than the app to see if the Web site has today's data from your inverter?

My DNO was fine discussing things and over a couple of days we verbally agreed the limit I then formally applied for. PVGIS will give you hourly forecast generation so you can get a good idea how much you'll generate, for how long and at what time. I suspect you'll be generating a fair wack for quite a few months but only you can guess at how much you'd be able to use

If you want to go above 3.68kw potential export to the grid, you need permission from your DNO so you probably want to speak to them to see what they'll allow. Without knowing what they'll allow you'll be guessing at how you should expand. The other thing to consider is if you're going to have circa 9kw of panels all facing the same way you'll end up with a peak of generation over a relatively short period of time. It might take a bit of effort to use much of that without being able to pack that into batteries.

Assuming the "4kWh" is kwp, that's colossal generation. Does your system track the sun?

CEF we're selling Longi 405s for £52 earlier this year. City Plumbing have 410s at £56 just now