Dillsue

As mentioned previously, you may have been able to do everything SolarEdge support did using SetApp with a local connection. You can update Set App with latest inverter firmware/software wherever or whenever you like and then update the inverter/battery from SetApp without connecting the inverter to the internet

For remote expert diagnostics. For easy failure monitoring. For easy performance monitoring. Not essential to make it work but very handy to have. Why do you think its only going to fail??

AFAIK Solaredge inverters dont need a cloud connection to operate, certainly the one I installed last year didn't as the WiFi aerial was installed months after the inverter was up and running. You've asked them to do remote diagnostics which you may possibly have been able to do via SetApp?? I don't have a battery so don't know what access you'd have via setapp. If you're heading to bin solaredge, don't forget you'll likely need to lift all your panels and remove the optimisers or buy the tool to disable the 1v safe shut down.

Speak to your DNO to get a feel if they'll allow more than 3.6kw of export. Theres a chance they will and you can put in a G99 once you know how much they'll allow. If you want lots of energy in the house but aren't allowed to export as much as you want to use, then set up a G100 export limitation. Unless you want to limit the combined PV AND battery to 3.68kw, you need to know what your DNO will allow before you agree a design and get quotes.

I don't think so. Seems to me that low 400 watt panels, 405's etc, aren't in vogue so prices have dropped and maybe being cleared??

No reason not to, but..... You'd need to work out how to seal between the panels to keep them watertight but allow replacement of seals/panels if there was a failure. Speak to Spirit energy who posted the picture?? If the fixings are from underneath then you'd need access from inside the roof so how they've fixed them in the picture with a room in roof setup is interesting

Assuming the Tesla batteries are Powerwalls, then your mate would likely have needed permission rather than "informing them". AFAIK, Powerwalls can only be installed by Tesla approved installers who are likely reputable and should have done things by the book. That'll likely involve your mate receiving paperwork so he should know for sure that the DNO gave consent. If not, ask the installer to confirm. Same for the solar. If he's charging 3 x Powerwalls and charging an EV at the same time, that's going to be a sizeable load on his supply which might explain the volt drop problem hes got. Try staggering the charging so the load is reduced but runs for a longer period of time? If he schedules the battery and EV charging to happen during the day, he can get a competent spark to monitor the supply and see if there's a volt drop and work out/confirm what's causing it. If the supply is dropping below statutory limits then there's a fair chance the DNO will have to bolster the supply.

The MCS standard requires install by an MCS registered contractor. If you were going to claim DIY to all other aspects of the MCS standard was the equivalent, then whoever did the work would likely need to meet the requirements of MCS registration whilst not actually being registered?? Otherwise how do you demonstrate equivalent compliance with the section that requires the work be done by an MCS registered contractor??

https://www.planningportal.co.uk/permission/common-projects/heat-pumps/planning-permission-air-source-heat-pump Unless you can find equivalent standards, then PD seems to be wholly dependant on MCS standards

I believe there's plenty of systems that will island the house and give several kw of power to the house. I've no personal experience but beleive tesla powerwall does it using their gateway, solaredge now support whole house backup and I think there's lots of others. Whatever you do make sure is certified for UK grid connection and from a reputable manufacturerer- you don't want to be powering the grid when a linesman is trying to fix a fault!

It will(should) only produce power on the back up/UPS/EPS AC output. The AC connection to the grid will shutdown if the grid supply is lost.

Maybe I'm missing something but there seems no point in battery storage if youve got a disc meter?? If you've got 10kwh spare PV and it runs to grid then there's 10 units "credit" on the meter for later use when you draw from the grid. Put the same 10 units into your own batteries and youve got to spend £1000's and suffer the charging/inversion losses when you want to use your PV later. Just make sure your usage is more than generation in the summer so the meter has a small net increase in the reading. Not sure how legit your set up is but net metering seems a reasonable thing to me

Don't forget that any contract you sign accepting a certain level of noise for a meagre sum will likely apply to any future buyer of your house and limit its saleability.

SPEN charged me £300 for a G99 a couple of years ago. Couldn't fault SPENs design guys

Data sheet says that's got an RS485 interface to an energy meter and the battery, so you'd be able to use your cat 5 cable to run RS 485 between an energy meter on the incoming supply and an inverter in the shed. With a base voltage of 240vac ish you're not likely to have volt rise issues at your inverter based on your calcs

Having an RS485 connected energy meter monitoring the import/export is the std way that Solaredge do charging/export limitation. I don't know if Givenergy have that option or rely on a CT directly connected to the inverter. If they rely on a direct CT connection then either the CT signal would likely travel a reasonable distance or they'll be limiting the use of their inverters by needing them to be mounted near to the incoming supply. You should be able to get that info from Givenergy??

If you mark up the area where the panels will be mounted with typical panels, you'll have a fair idea of what you likely max output will be. You can then tell them that figure and they can move the supply design forward with a bit more certainty. In your shoes I'd be using figures of 450watt/panel with the panels 1150 wide x 1800 tall which includes gaps between them. Otherwise get a local installer to size thing up off your drawings

The DNO and MCS are completely different things independent of each other. DNO interraction is to ensure grid safety/security isn't compromised. Search the forum for G98 and G99 and there's a mountain of info MCS is to ensure your generation is from renewables and meets certain standards

Unless you've got a massive array its almost certain you'll use everything you generate in the winter and a fair chance you'll need more on occasion. The 4.5 kw you've got on a pallet will just scratch the surface in the winter. Even with a big array how are you going to power things if you have a run of bad weather. What if you have a breakdown without the back up of a grid connected system? Assuming your house already has a mains supply, connecting up PV costs can be minimal. Export less than 3.68kw and DNO costs are £0. Getting a spark to make the final connection to your consumer unit can be a couple of hundred £, less if youre well acquainted. The rest you can do yourself with research.

Restrictions like these need to change rapidly. If the IPCC are correct then the bulk of planning considerations need to be dispensed with for essential infrastructure. I beleive current planning can limit the duration of a turbines presence so they can be "temporary", renewed periodically whilst we're in a climate emergency.

Compulsory purchase is going to add to the £ burden. Those that object to essential infrastructure, which benefits them and wider society, pay a NIMBY tax which is applied as a credit to the energy bills of those that live with ugly infrastructure:)

Why off grid? Is this for powering some parts of a grid connected house?

Have you looked at PVGIS to see what you'll likely generate. It'll give you year round breakdown so you can see realistically what you'll have spare to export year round. AfAIK the only way you'll get reasonable export rates is with a variable export tariff like the ones Octopus offer but I think you need to give them control of your battery or be hands on exporting when rates are high

My understanding of things is you shut the inverter down before switching any isolator so there's unlikely to be any power flowing in the DC or AC side. Thats certainly the case with solaredge optimisers but maybe different with string inverters?? You'll not get any arcing if there's no power. Not sure how much arcing you'd get, if any, with a correctly rated DC isolator. Bit lax of the manufacturer if that was reasonably possible

Stop doing all the things we shouldnt in the next 5 years, job done with recovery over the next decades. Like I said gonna be very painful and expensive. Particularly in the first world, we don't have the appetite for it as most people aren't capable of assessing and appreciating the risk to them and their offspring and don't give a monkeys about the billions they aren't acquainted with.