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Green Building Bible, Fourth Edition
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    • CommentAuthorneelpeel
    • CommentTimeJun 9th 2022
     
    Now I'm confused (easily done). Do you mean that the CU input needs to be 230V, so there needs to be a voltage ''rise' to the inverter to account for losses? That would make sense. But 262V isn't anywhere close to the 1%VD target described by Revor?

    Found a Voltage drop calculator here...
    https://midsummerenergy.co.uk/voltage-drop-calculator

    This suggests a drop of 1.2% (2.7V) if I use 6mm2 cable. Does that sound ok?
    • CommentAuthorphiledge
    • CommentTimeJun 9th 2022
     
    There doent "need" to be a voltage rise to the inverter, its just inherent in electric circuits.

    UK supply voltage is nominally 230vac with a tolerance of +10% and -6% so up to 253vac is allowable. Our house voltage is 250vac with no load. When your inverter is pushing 16amps down 30meters of cable there will be some resistance with any size cable and that resistance will vary depending on the cable size/length. When the inverter is trying to push 16amps to the consumer unit it has to increase the voltage slightly to make the 16amps flow. If the resistance of the cable is high because the cable is too small/long, the voltage will have to rise more to get the 16amps to flow. If the cable resistance is lower because its a large/shorter cable the voltage wont have rise much to overcome what is a smaller resistance.

    If you start with a high house voltage such as 250vac and youve got a 2.7vac rise then that will push the voltage at the inverter to 252.7, just shy of the UK limit. Now its only the inverter that is seeing that voltage because the other end of the cable is at house voltage of 250vac so the house remains within limits but the inverter is pretty close to the limit. Whether thats a problem for you or your spark is up to you. The inverter and any reputable cable/isolator will be rated for way beyond normal mains voltage so no problem there. There may be more issues though.

    If your not using any PV when youre generating at the 16amp limit that 16amps has to find its way into the grid. If your grid connection is poor, like ours, not only will the inverter voltage rise above the house voltage, the house voltage will rise above the grid voltage. In this situation you could see the house rise to the UK limit with the inverter a few volts over, or whole lot go over the limit. With a G98 16amp limited inverter I beleive the DNO is obliged to modify the grid to keep the supply below the 253vac limit. With just one of our systems running our house voltage is well over 253vac so the DNO is upgrading our transformer FOC.

    Ignore the 262vac as thats under abnormal conditions if something in the design has gone seriously wrong
  1.  
    Neelpeel
    I think with a bit of thought , polycarb roofing screw down glazing bars would work.
    • CommentAuthorrevor
    • CommentTimeJun 9th 2022
     
    Ideally if you can is run as much of your distance as DC to the inverter as this will be at higher voltage 400V plus and therefore can carry greater current so smaller gauge cable then leaving a minimum amount from you inverter as AC 230V. If your distances are not large then it probably matters not but it gives a leeway in sizing the cables
    • CommentAuthorneelpeel
    • CommentTimeJun 9th 2022
     
    Thanks for the wiring tips guys. Some things to think about then. I don't really have space for the inverter in the house so I guess I either need some hefty cable (and get the sparky to do some calcs) or I need to build a mini 'lean-to' unit to house some electronics on the end of the house. Looking at cable, it seems that moving from 6mm2 to 10mm2 would only cost an additional £60 or so, so that would seem the sensible route.

    jamesingram, I was just looking at the very same yesterday! I think it would work ok on the vertical joins, but maybe not so well on the horizontal as water might pool and seep through if the corners are not perfect. My shallow angle will not help.
    I did find an interesting thread where some in Aus made a carport and sealed them with UV rated silicon. Looks neat but can't see it lasting 20 years...
    https://forum.solar-electric.com/discussion/10465/making-a-waterproof-roof-out-of-solar-panels
  2.  
    Posted By: neelpeelI don't really have space for the inverter in the house so I guess I either need some hefty cable (and get the sparky to do some calcs) or I need to build a mini 'lean-to' unit to house some electronics on the end of the house.

    The inverters we get here can be mounted on an outside wall without additional protection and I suspect yours will be the same so a mini 'lean-to' unit should not be needed.
    • CommentAuthorrevor
    • CommentTimeJun 10th 2022
     
    I would not install one in a house anyway and not all inverters can be installed outside so check carefully the specification. Mine has to be indoors has wide temperature and RH tolerance, condensation inside the inverter is always a risk from what I can make out. Water and electronics are not friends. From what you have stated I would not think you need 10mm cable. I have 55m from the 6kw array to the inverter in an outbuilding and 15 m from there to the CU in the house. This is all in 4 core SWA. The array to inverter being DC at a higher voltage the cable size is fine SWA is rated for 800V so voltage rating wise is ok also.
    • CommentAuthorjamesingram
    • CommentTimeJun 10th 2022 edited
     
    Neelpeel , I think what would be needed is some kind of oversized cross shaped capping to link horizantal and vertical bars.
    ive no idea if anyone makes it. Ill have a search.
    You could just use the GSW trays without felt as they have a central access hole.
  3.  
    Wonder if a combination of horizontal tapes (top and bottom 10+10 with panels screwed together and vertical bars might work?
    https://advancedacoustics-uk.com/search?q=Resilient+Sealing+Tape+-+10mm+thick+
    • CommentAuthorneelpeel
    • CommentTimeJun 14th 2022
     
    Thank James. It just doesn't seem that there is an easy solution out there and I could see myself chasing leaks for the next 20 years...so I've decided to stick on some steel box profile. Should last the duration.
    • CommentAuthorcjard
    • CommentTimeJun 15th 2022
     
    @renewablejohn is a leaf 3 phase? I thought they were 1ph
  4.  
    Posted By: cjard@renewablejohn is a leaf 3 phase? I thought they were 1ph


    The leaf is just a battery with the old ones being 24kwh and the newer ones 40kwh. The 3 phase I believe is down to the inverter but if you wanted you can break down the 24 kwh battery into 3 x 8kwh batteries and there is a video on you tube of an Australian company which provides the cabling and battery management system capable of doing this.

    I am a total rookie trying to sort out a system to use these bifacial solar panels. I know what I want to end up with but totally confused on how to achieve it.
    To date the only thing I have achieved is the method of mounting the bifacial panels vertically in 2 rows with a tilt mechanism to turn them horizontally for a crude form of tracking.
    I can see the advantage of battery storage but cannot justify the cost unless I use an EV like a Leaf and a V2H system. But then I also want 3 phase to charge the leaf direct from the solar.
    • CommentAuthorphiledge
    • CommentTimeJun 15th 2022 edited
     
    Posted By: renewablejohn
    I am a total rookie trying to sort out a system to use these bifacial solar panels. I know what I want to end up with but totally confused on how to achieve it.

    I know nothing of V2H but a quick internet read suggests its in early developement stages with limited trials going on. Because its V2House and most UK houses are single phase supply, I think youll be waiting along time to integrate 3 phase into V2H. Single phase bidirectional chargers seem in limited supply so I guess 3 phase ones are even more limited if they even exist outside of a developement lab.

    Maybe speak to one of the trial operators or install a 3 phase system but forget the V2H for now??
  5.  
    <blockquote><cite>Posted By: philedge</cite><blockquote><cite>Posted By: renewablejohn</cite>
    I am a total rookie trying to sort out a system to use these bifacial solar panels. I know what I want to end up with but totally confused on how to achieve it.
    </blockquote>
    I know nothing of V2H but a quick internet read suggests its in early developement stages with limited trials going on. Because its V2House and most UK houses are single phase supply, I think youll be waiting along time to integrate 3 phase into V2H. Single phase bidirectional chargers seem in limited supply so I guess 3 phase ones are even more limited if they even exist outside of a developement lab.

    Maybe speak to one of the trial operators or install a 3 phase system but forget the V2H for now??</blockquote>



    This is the sort of system I have been looking at.

    https://voltaconsolar.com/grid-tie-with-energy-storage-systems/voltasol-on-grid-self-consumption/voltasol-hybrid-inverter-10kw-pylontech-lithium-battery.html?utm_medium=cpc&utm_source=google&gclid=CjwKCAjwqauVBhBGEiwAXOepka1rVvlDsSvEAQzEcGyDuPzAqGl3tAsphAKvAzfelNHBa6_6cD0OUhoCJCAQAvD_BwE

    Which will then enable me to run the house and fast charge the leaf battery using 3 phase. Just dont know as yet how the V2H links in from the leaf battery back into the existing energy storage system.
    • CommentAuthorphiledge
    • CommentTimeJun 17th 2022
     
    The inverter you linked to seems a standardish inverter/battery combo.

    If you google "V2H charger" you could ask the handful of manufacturers to explain how the bidirectional chargers work and would integrate with a 3ph system
  6.  
    Posted By: philedgeThe inverter you linked to seems a standardish inverter/battery combo.

    If you google "V2H charger" you could ask the handful of manufacturers to explain how the bidirectional chargers work and would integrate with a 3ph system


    Looks like the choice is a wallbox quaser but limited to a leaf or mitsubishi or wait for the quaser 2 for the majority of cars. Both appear to allow fast 3 phase charging as well as use of the vehicle battery to supplement a small household battery.
    • CommentAuthorrevor
    • CommentTimeJun 17th 2022
     
    Have you costed a 3 P charger? I have 3 P but was told the cost of and installation would be several £k though did not get a proper quote. It would be 22Kw charging. A DC charger you are in the £20K region which is the only way to get fast charging. Few vehicles as I understand will have an on board 22Kw charger and are likely to be the more costly EV's.
    I too would be interested in V2H but think we are way from that just yet. Will EV manufacturers be happy to warranty the battery if used this way?

    Posted By: renewablejohnallow fast 3 phase charging


    What do you mean by this staement?
  7.  
    Posted By: revorHave you costed a 3 P charger? I have 3 P but was told the cost of and installation would be several £k though did not get a proper quote. It would be 22Kw charging. A DC charger you are in the £20K region which is the only way to get fast charging. Few vehicles as I understand will have an on board 22Kw charger and are likely to be the more costly EV's.
    I too would be interested in V2H but think we are way from that just yet. Will EV manufacturers be happy to warranty the battery if used this way?

    Posted By: renewablejohnallow fast 3 phase charging


    What do you mean by this staement?


    The prices your quoting seem way out. I am looking at 3k for a hybrid 15kw 3 phase 48 volt system and another 2k for a starter battery pack. (main battery looking at a leaf 24kwh).

    The fast 3 phase charging refers to the function of the Quaser not being restricted into using single phase but able to use 11kw 3 phase to significantly reduce charging times like a fast charger. Have a look at the Quaser specs and the upgraded Quaser 2 specs. Think the Quaser is 5k but my thought is that I could easily spend that on batteries and still not have the capacity of a leaf battery. The leaf battery holds approx 3 days of my normal household usage.
    • CommentAuthorphiledge
    • CommentTimeJun 18th 2022
     
    Have you got a link to the Quasar specs showing 3 phase? All I could see in electrical specs was reference to single phase for the Quasar

    From what I could see the Quassr2 seems to have been developed to support islanding so the house can be powered from the car in a power cut. I think that the UK DNOs have some pretty strict rules on islanding systems so make sure youve got the cost of kit to isolate yourself from the grid included.
  8.  
    Looks like I got it wrong the wallbox quaser you can discharge as part of the V2H but the 3 phase charging is the wallbox pulsar plus being upto 22kw

    https://wallbox.com/en_uk/wallbox-pulsar

    The electric input quoted above.

    Also found Anderson EV 3 phase charging which links into 3 phase solar charging but looks like it is a minefield as to what cars can actually accept 11kw or 22kw fast charging.
    • CommentAuthorphiledge
    • CommentTimeJun 18th 2022
     
    From the snippets Ive seen V2H is very much in its infancy and very very limited in compatible vehicles. Given that youve got the PV already it might be worth finding out from a few V2H manufacturers how their units would integrate and crack on with a compatible system but install thd V2H system in a year or 2.

    If youre going to buy a compatible car and charger its quite an outlay as youll likely need a fairly new car if you want the V2H functions. Im sure theres clever people out there that have already by passed the cars AC charger to hook up direct to the batteries, but that's another topic altogether!
    • CommentAuthorneelpeel
    • CommentTimeJun 21st 2022
     
    So, I sent a spec to a handful of local MCS certified sparks last week to get an idea of costs and timescales. Only 3 have came back to me and all 3 have stated that they have +6 months work booked up and are not taking on jobs.
    Looks like I'm heading down the DIY route then.
    Frame is mostly up and box section steel is 3-4 week delivery so some time to play with.

    I was surprised to receive a call from SSEN today in response to a query a lodged a few weeks ago...I was asking if I can install higher than the 3.68kW limit, install a 5 or 6kW inverter (to give future upgradeability), but set it to cap at 3.68kW in the software. I saw this on a forum as a known solution. Apparently though the inverter MUST be 3.68kW rated or less and a software setting is not allowed.
    Now considering if it's worth going down the G99 route now so that I have dispensation for greater than 3.68kW in the future (I can see myself wanting to upgrade later).
    • CommentAuthorphiledge
    • CommentTimeJun 22nd 2022
     
    Posted By: neelpeelApparently though the inverter MUST be 3.68kW rated or less and a software setting is not allowed.


    I think what they should have said is the software limit cant be altered by the user. AFAIK its commonplace for the limit to be set in software, but its set in the factory or by an engineer with factory approved software access. The ENA G98 certs for the smaller range of Solaredge inverters specifically state they all use the same hardware and each inverter models limit is set in software.

    It maybe that you can get a larger inverter derated by the factory but for a G98 connection you need a type approved inverter and thats likely to be problematic for a custom configured inverter.

    Other than going for G99 now you could fit a 16amp limited inverter now an either replace it or add a second inverter when you get your G99 approval. Certainly for Solaredge inverters youre only going to loose a couple of hundred pounds selling a working secondhand inverter, at the moment anyway!!

    You do know that many inverters will accept way more PV input than their rated AC output. A Solaredge SE3680H is capped at 16amp/ 3.68kw but will accept uo to 5.7kw of PV input. If your panels have a range of orientations so they are not all hitting max generation at once youll likely be able to conect way more.
    • CommentAuthorrevor
    • CommentTimeJun 22nd 2022
     
    Most inverters export limit (AFAIK) is now set via software accessible via engineers password. I guess if you are doing to your own install you should get the password with the inverter, you will need it to access other functions anyway. As an user you are not supposed to be able to have access to the password but you should be able to get it. If stuck you can ask on some electrician forums if anyone knows the PW for the particular make. Perhaps your choice of inverter could include PW availability.
    • CommentAuthorphiledge
    • CommentTimeJun 22nd 2022
     
    I would caution against lifting the export limit without consent from your DNO. Theres a rush to install PV at the moment and if people start exporting what they choose we'll collectively start frying the grid and our neighbours.

    If your grid connection can take extra export, in my experience getting G99 consent is straight forward
  9.  
    I am having a similar problem on getting a system installed. As a solution I am looking at a hybrid system with batteries but it seems far easier to install as a non grid tie system. Is there any reason why the Grid tie could not be done later when the sparkies are not so busy.
    • CommentAuthorphiledge
    • CommentTimeJun 23rd 2022
     
    AFAIK other than a different inverter and a cabled connection to the grid theres little difference between grid tied and off grid systems. If youre able to install an off grid system then getting a spark to connect up your inverter to the incoming supply shouldnt be a problem- doesnt need to be a solar installer to do that.
    •  
      CommentAuthorDamonHD
    • CommentTime7 days ago
     
    Hi,

    I may have missed something critical above, but that's a bit of a sweeping statement IMHO.

    Off-grid systems, depending on intended use ... almost always must have storage to aid regulation if nothing else, will usually have parts running at much lower voltage and higher current (my entire off-grid system runs a a nominal 12V), may have a dump-load to make use of power in the absense of the effective infinite sink that the grid provides and must have one for sources such as wind, the inverter is often also a controller to manage the storage, etc, etc.

    Rgds

    Damon
  10.  
    Anyone have experience with PV and High voltage transmission lines. 132kv or 400kv. I ask as I was going to locate the PV panels just to the south of a HV line so not affected by shading but rumour has it the magnetism of the HV line screws up the PV output and really PV panels need to be a minimum of 200 mtrs away from the power line.
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