Dillsue

I believe Greg Jackson is a former software engineer and well into his tech so I guess their systems have been developed to be flexible and easily reconfigured to chop and change products whenever they want

??? Don't really understand where you're coming from

We didn't need to implement limitation so I can't tell what they do practically.... I was just giving you the heads up on cost/risk and potential hassle giving a demonstration for them to witness. Might be annoying to change the inverter but it might be better for you when you factor in the hassle and possible cost to you of continuing with current inverter set to a G98 limit. Only you know if its worthwhile.

It's not comparable as the Solaredge unit is factory limited to 3.68kw so it's G98 compliant out of the box, yet can still handle a large PV input. Your Solis can handle the PV input but needs to be installer throttled to get down to 3.68kw max, hence the G99/G100 I'm not sure if there are other G98 inverters that can take your PV input, but a change of inverter could take you back to a simple G98 notification. One other thing to be aware of is that your DNO reserves the right to witness the export limitation and if its not professionally installed may want to?? Although we ultimately didn't need export limitation our DNO charged £360 to witness the limitation!!

G98 is self limiting to 3.68kw by definition so it's almost certainly a G99 + G100 application that you did/ need to do. It's technically not possible to DIY a G100 compliant system because the limitation setting has to be password protected with a password that only the manufacturer or certified installer knows. The reasoning behind that is if the user has access to the password they can raise the limitation setting whenever they want. Be conscious of this in any discussion you have with your DNO. Don't know what inverter you have but there are G98/3.68kw inverters that will accept your 6.5kw of PV. Latest data I've seen for Solaredge is you can have twice the inverters rating in DC input so a G98 SE3680H can have 7.3kw of PV hooked up to it. No peeing around with G99 or G100, just notify your DNO when the system is up and running.

If you want to get on one of their export tariffs then you'll need an MCS cert/number together with confirmation from your DNO that they approve your export connection, unless you registered your interest and got an invite to join the non MCS trial that they are currently running. That's how things stood last week. If you're installer was MCS accredited when they did your install and you can show you paid them, I'd be fairly sure you'll be able to get an MCs cert from MCS themselves. Might take a bit of coaxing out of them but if the cert is due then you should get it, eventually.

Ah, OK. Not sure if it's always been the case but when I applied to Octopus for export payments last week they didnt need the MCS cert but just the number. I guess they've got access to the MCS database cos they verified the number within seconds.

Talk has turned to action and they're running a trial. Ferdinand was saying he had some issues with documentation which I'm interested to know about as they may pop up for me

Do you know if this is 2 supplies off differing phases with 400 volts between them, or 2 supplies off the same phase with 0 volts between them? With a 4kwp array/battery you'll do well to power 1 ASHP and 1 EVC so a single inverter/battery on one supply would likely use everything the array can provide for most of the time. If you want to charge the battery(s) on a TOU tariff you could have a single battery and a pair of contractors switching the battery between the 2 supplies as required or a battery on each supply. If you've got 2 differing phases coming into the house you may get a 3 phase inverter to run on 2 phases but youd need to speak to the manufacturer to confirm

What was the issue?? We've just applied for Octopus export and it was straight forward- connection confirmation email from our DNO and the MCS cert number. Smart meter went in a few weeks ago so as I understand it Octopus have to request an export MPAN from our DNO and then we're good to go.

Someone posted on here a few weeks ago that they'd been accepted with a non MCS system, but there's a few hoops to jump through based on the requirements they sent me. They're running it as a trial at the moment and are asking for the following- Building control approval for the additional load on the roof Electrical installation certificate from a part P spark. Letter/email from your DNO confirming they accept your export to the grid £250 admin fee You may get an MCS contractor to sign off your installation but they'd likely want a hefty fee to do so and they'd likely have to check through your install to make sure it's as if they had done the work. MCS may not allow it so you'd be asking a stranger for a big favour??

Not sure where he gets his 100% renewables by 2035 from as UK govs BEIS think differently. See section 4- Updated energy and emissions projections 2021 to 2040 - GOV.UK https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/1111625/updated-energy-and-emissions-projections-2021-2040.pdf

We fitted a Thermomax system in 2006 and other than a maintenance fluid change its been hassle free. I think they were bought by Kingspan but no idea if they are still in production, nor if spare tubes are available

If you buy an inverter with a 13a socket built into it and plug an appliance directly into it then there's no building control or part P spark needed as its all factory assembled/tested and deemed safe. The moment you start installing 240v cabling/sockets then it comes under BC/part P

I suspect Octopus are asking for what an MCS installer is supposed to do rather than what they actually do. In asking for BC sign off youre unlikely to get away with what MCS installers get away with- our roof was never surveyed for our MCS FIT installation.

Assuming V2G/H gets approved and publicly available in the next year or 2, are you saying Leafs will be a non starter with no compatible bi directional chargers available? I'm guessing there'd be a market to sell Chademo units into??

And if the home built untested/certified mish mash doesnt shutdown when the grid is down,what happens to the linesman trying to fix the fault down the road?

The posts above using a Leaf for V2H/G both use a Quasar or Indra unit which seem in short supply second hand and aren't available new. Anyone aware of any other units to hook up a Leaf without modding the car? Ideally grid tied but I think that's not yet legit outside of the official trials??

Thay don't need to approve what you're connecting so long as it's G98 type tested and on the ENA database. Just notify them once it's connected. Anything else needs prior permission via G99

Bear in mind that, AFAIK, both those bi directional chargers are grid tied so should shut down when the grid goes down and wouldn't work in an off grid set up, if that's what you're after.

Is that all UK models? Do you have a reference for that? I've been looking at maybe using V2X in the future and all I can see for the leaf is post 17/18 models that support it in the UK

There's a similar thread in the PV section about sizing off grid systems so have a read. I don't believe your Leaf supports exporting from the car to external load so you'd likely be looking at modding the car to get access to the battery. I think it's the 40kwh version from 2017/2018 that support export???

By all means tinker with PVGIS but it's output is meaningless if you don't know what your consumption is. You need to work out your daily demand. Assuming you're not currently living in a doorway, get yourself one of the basic plug in energy meters and start to understand what each bit of electrical kit consumes over a day. Then you can add everything up and have an idea of how much you consume. If you're on your own metered electric supply, take daily readings and youll know exactly now much you are using per day. Generators are cheap to buy if you want to be fully off grid, but why? For a couple of hundred £ a year standing charge the security of a grid connection is a bargain. You don't have to take any electricity from the grid but it's a nice bit of insurance to have. Obviously if there's not already a supply where you're living there's a connection charge.

Remember that in summer your usage is likely low and potential generation is high. In winter its the reverse so if you spec a system for worst case winter load, it'll massively overproduce in the summer. Are you properly off grid as in no grid connection available or just want to be more independant?

If its a feed to the hot water tank, you'll likely want the heat from the heatpump to go to the tank rather than heating the air even if its within the thermal envelope. If the pipes aren't insulated you're giving the HP more work to do at a time when it'll likely be running at a poorer COP heating to a higher temperature for the hot water.