Dillsue

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

Just noticed the price your quoting for 325watt panels....£100 each seems very expensive!!

As post above, OFGEM changed the rules in Dec 2021 and loads of places I've seen don't reflect theses changes. Someone sent me link recently to a Guardian reporter saying you can't change anything which isn't what the OFGEM guidance says!

You can chop and change a FIT system without loosing the payments for the original capacity. Google " guidance for FIT generators" and it's all explained in there. Here's the link https://www.ofgem.gov.uk/publications/feed-tariffs-guidance-fit-generators see section 3

Going down the second inverter route likely means another G99 application so a tad more involved. Are all the panels going to be facing the same direction as that has a big bearing on peak generation and hence what you can have on each of the existing MPPTs. How many new panels do you want to add?

Unless you're on the old FIT scheme, AFAIK all UK payment schemes are based on export rather than generation so maybe a physical meter is obsolete now?? I'm assuming France could be the same?? Generation stats should/might be available on the monitoring platform

Google translate says 3 " MICRO-ONDULEURS THALEOS TRANSFORMER 2 "are micro inverters. If the app shows the panels generating then youre up and running. Anything you generate will be used to power your house and if there's anything you don't use it'll likely go the grid to power your neighbours

Fair chance. Grey conduit from roof is AC from micro inverters to surge protection then to Q2. Connection to main consumer unit is via RCD and Q1??? 2 cables and earth in the cable glands. All switched on so maybe already running or needs MCB in main consumer unit switching on?? Could be something completely different but micro inverters would work with what's been shown so far.

Well its not that obvious. You're posting on a UK forum and over here we have a single connection for both import and export. There's no second connection required to connect solar PV to. Maybe it's different in France but I'd be surprised if it was. In the UK you need an export MPAN, but that's not a second connection

Haven't you already got a connection to the grid to power your house??

The current varies with sunlight levels hence the difference in rated current for STC and NOCT

Last few pages from fig 6 onwards show the varying voltage current. The voltage looks very low as the curves are for a single cell, not a full panel!

Easiest way to add the bigger panels is to wire them to a separate MPPT input on your existing inverter. Next easiest, but may not be ideal, is to get someone to calculate the output for the various panel combinations to see if they can be wired to your existing inverter, if no spare MPPT input. Next is to replace your inverter with one that has a spare MPPT input. Lastly add optimisers/micro inverters which allows you to mix and match panels freely