Dillsue

I think the latest Leafs support V2H but I understand its a bit of a niche just now so probably worth doing youre homework as to your V2H options. If youve already got big battery capacity then it changes your options somewhat and 15kwp is unlikely to be "to much"

Having your panels facing different directions gives a longer spread of generation which could be more useful than a massive peak depending on your motivation for installing PV Whether 15kwp is "too much" depends on your motives and set up. In the summer youll likely have too much for self use but in the winter you could cover much of your usage if you have a battery bank. Batteries come with a big environmental footprint, so a consideration if one of your motives is environmental. A long spread of generation may negate the need for batteries or allow a smaller battery pack. If youre happy for excess to go to the grid, and the grid can handle it, then youll never have too much and a gas power station can throttle back a bit on sunny days. On the flip side, if you want to keep everything yourself youll likely need batteries, PV diverters, an EV etc to grab as much as you can

For this reason DNOs linesmen might not be too happy with you

Technically youll likely need an electrical inspection even If off grid- see previous comments. For grid tie theres-No local authority involvement unless you want it. No MCS unless you want it. Unless you want something else the only additional formality for grid tie is G99 at circa £300. Im sure someone posted that their DNO processed a G99 for free??

I know virtually zilch about battery charging systems so Ill take your word for that. Whats the plan for a failed inverter? If your mate is going to keep a grid connection for battery charging and pay the standing charge then why have the system off grid? You might have to pay a G99 fee to do things legit but its a one off payment thats probably quite small in relation to what hes likely to pay for his PV just now.

Not sure where UVCs came into the comments on warranties as the chat was about PV and you were commenting on MCS and SEG.... clearly not UVC related.

At the time you "occasionally" connect to the grid to charge flat batteries/deal with a failed inverter, its a grid connected system so needs G98/G99 compliance. I think the wiring regs apply to surprisingly low voltages which would include your off grid PV output if its series wired. Youve stated theres an occaisional grid connection so any of that wiring falls under the regs TBH its one thing installing stuff for yourself when theres a bit of uncertainty, but doing it for someone else is a different kettle of fish.

Thats not the case for lifetime warranties on Solaredge kit as they need kit installing and maintaining to their instructions. No need for any specific skill set/accreditation other than being able to read and understand technical english, and pay the extended warranty fee. I suspect that other manufacturers are the same??

Fairly sure all the inverter manuals give recomended sizes, but as Radian says a 16A unit with B curve will likely fit the bill

Only if dragsterdriver pushed a piece a wire up the inside of both MC4 connectors at the same time and held them. Probably no more lethal than working on the roof?

Solaredge do as standard but I dont think Tigo do. The Solaredge safe 1 volt output can be overriden with a Solaredge tool and then give full output in the same way Tigo units do. Best to check with a meter if you dont know the spec of the optimised system youre working on.

I think the OP sensibly came looking for clarification/advice about something he already seemed clued up on. If he already knew exactly what to do hes not likely to have posted??

I think that your eleccy supplier can upload unit rates to your display so you can see what your using in £, but if you set the display to show units it will display those

Normally, on this forum it is!😁

Normally?? Without trawling the forum I think its normally 3 or sometimes 2 letters, usually h, k and w with random capitalisation, if any😁

Read on a bit and....

Kwh last time I saw it.....sat at the inverters 16amp limit😁

You probably need to get your head round whats involved in running off grid and get the buy in of everyone whos going to use the house. Have a good think about all the things you do over winter and consider if youd be able to do those if youd had a cold dull week when the ASHP has taken virtually everything out of the batteries and PV has put nothing back in. Obviously if youve got your own solar farm and a container of batteries, going off grid is reliably feasible, but more likely the 50p/day electric standing charge is a bargain for the backup of a grid connection.

My daughters smart meter shows export and they are on a standard price capped varable tariff with no SEG

Its massively different to driving on an A road as on the salt flat theres the option for both cars to move a long way from the line and virtually eliminate the risk. Going back to the OPs level of risk and hes already got a spark on site that could megger the cables even if not taking responsibility for the full PV. The OPs questions are well written and list all the things that need doing to complete the roof work......hes just looking for confirmation. All suggests low risk to me

Nope. The OP wants to get the roof work done while he waits for a spark to come available. No mention of doing anything more than running DC cables to isolators.

Hopefully the OP can see that none of this relates to what he wants to do and can safely move his job forward and get the scaffold off hire.

With individual optimsers per panel theres a minimum of 8 units specified for all the smaller inverters which I guess is to maintain minimum power input into the inverter at lower light levels. You might hit problems with that, but maybe not. Considering Radians very valid concerns, youve nothing to loose by powering up, pairing the optimiser and seeing if it generates. Hopefully its obvious but switch the AC isolator off before unplugging and dont leave the plug unattended without ensuring no one can unplug it. Not that you should rely on these safety features but I belive the SE3680H and smaller inverters shutdown within 0.25 seconds of mains loss and they have an inbuilt RCD. If youre not clear on the risks/hazards probably best to wait for a spark to connect you up??

If youre looking for a solar experienced spark you might be waiting a while!! In the meantime, with a 2kw inverter, you could plug your inverter into the nearest 13amp socket to get it powered up for testing. Not that Im endorsing it, but you could then leave it plugged in to grab some generation while the sun shines:)

Yes, your AC isolator wiring isnt best practice but you can see from the wiring guide of the DC isolator that best practice isnt always followed. The DC isolator wiring is using 2 poles for +ve and 1 pole and N for negative, the thinking being that if 1 pole welds closed theres a second pole that should still break the circuit when the isolator is turned off. That wiring guide would have been better wiring +ve In into L1, a link fitted from T1 to L2 and +ve Out wired to T2. Same principle for -ve. Keeps the Line/live and the load on the correct sides of the isolator. Having already wired your AC isolator I personally wouldnt rework it to best practice, but maybe put some tape over the terminals fed from the CU and write "Line/live" on it. Be a reminder for you if you ever have to go back in there