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Anyone Home Solar Charging?

Discussion in 'The UK and Ireland' started by Fullerene, Aug 2, 2019.

  1. Akikiki

    Akikiki A'-Lo-HA ! y'all

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    Its not broken down in parts. The details would not help you since I can't even guess what the panels, and the Solaredge retrofit and labor is individually. I kept some of my panels and replaced 75% with new stuff. So, it won't help to give the total.
     
  2. VanillaAir_UK

    VanillaAir_UK Waiting patiently for a tow

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    Alas 12kWp is a mere dream for most here in UK as we are limited by 16A export install, technically 3.6kW but 4kWp is allowed (per phase). Very rare to find 3 phase, usually only commercial, so 4kWp is the typical domestic limit, assuming you have a roof big enough to even take that - many don't. Above that, you need to seek permission from DNO (power supplier) and/or use export limiting. Some cases, oversized panels on a single 3.6kW inverter is allowed, but its not the default and there is only so much you can over power an inverter by so you might get an extra kWp or so. If DNO are not happy, then you are stuck, but even if they are, you may need to prove certain things to them, including getting them to witness tests which is rather expensive. Its often very location specific so no hard and fast rules and done on a case by case basis where as under 4Wp is a retrospective notification. 4kWp also use to be a cutoff before FIT limits dropped significantly, but since FIT is negligible these days, its not so much an issue. No net metering for us, no alterations without more red tape.
     
  3. WannabeOwner

    WannabeOwner Active Member

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    My issue with PowerWall for car charging is the losses electricity->PowerWall->electricity->Car ... I haven't done the sums carefully but my guess is I might as well just buy Grid Juice :( given the over-capacity of PV I would need just to cover those losses.

    Maybe I just need to "get over" that ?

    Too much store put by for payback IMHO. Lots of work to do to save the planet. Clearly folk here are already doing plenty - either got, waiting for, or wanting an EV ... and in this thread also have PV.

    I forget the exact headline but I think something like needing to reduce emissions by 80% - those of us that can clearly need to do more than those that can't in order to achieve that.

    The EU objectives are:

    Key targets for 2030:
    • At least 40% cuts in greenhouse gas emissions (from 1990 levels)
    • At least 32% share for renewable energy
    • At least 32.5% improvement in energy efficiency
    And UK:
    The UK is committed to reducing its greenhouse gas emissions by at least 80% by 2050, relative to 1990 levels

    2050 Pathways

    My house used way more energy in 1990 than it does now ... but I wasn't the owner and previous owner had money to burn, and kept the multiple oil boilers on throughout the year :eek: But that was then ...

    I consider that my family are well ahead of the curve - EVs, Biomass boiler, Solar Thermal and PV, Passive House. Nonetheless my family has set about reducing to "Net zero". Too early for me to say how difficult that will be, but I'm not resting that I am already doing better than my peers; payback is most definitely not on my priority list. And before you say it: No, I don't have ...

    ... more-money-than-sense

    I think the most likely scenario is that Solar PV will give us spare juice in the day, more so in Summer (at our Latitude of course, but Wind is greater in Winter, so maybe "all year" daytime peak. So lowest tariff will become Day Renewals Peak. Many cars will be "parked at work" so will need employers to provide chargers - and then you can export the PV from your roof to grid and Employer can buy it back ... and probably sell it to you :(

    If you have another EV at home then I think that might look rosy for day time charging - either from your own PV or from Peak-Renewals cheap tariff.

    We are looking at increasing our PV panels from 8 to 25-ish. I don't think that one Powerwall will be enough to smooth that out (even if DNO allows the export without curtailment, which they might, I'd prefer to use-what-I-make), but an always-at-home additional EV is an attractive proposition. We have two cars, an EV and the other still ICE for long journeys "too difficult" for MS 90 ... but a new MS LR would solve those journeys, so could then change ICE to M3 ... and could then alternate commute-vehicle and day-charge the other one ... thereby not needing 2nd PowerWall and moving the £7,500 to purchase of M3.

    Plus your sunshine is WAY better than ours :)
     
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  4. Fullerene

    Fullerene Member

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    Glad I’m not the only one that has spent ages looking into this, 4kWp lighter rules were good for uptake. It seems anything above this requires the same paperwork as a nuclear plant!

    Octopus Agile dynamic tariff in the uk looks interesting: Introducing Outgoing Octopus: The UK's first smart export tariff

    I have space for a more solar but the UK red tape makes it hard. Having spare capacity and not exporting seems terrible, I’m happy to have dynamic limits via the new G99/100 (?) requirements, but the bureaucracy seems to make it impossible, if not financially unviable, for 4kWp to 50kWp to export. I’m wanting to do this but I don’t want red tape making it unaffordable.
     
  5. Fullerene

    Fullerene Member

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    I have done my best on a limited budget, however telling my kids to put a jumper on saves a lot of carbon.

    For UK Carbon / Energy Targets EV cars will be a relatively easy change, honestly believe we are at the tipping point. The difficulty comes in upgrading the housing stock, more likely to get Nuclear Fission working by 2050 than resolve UK housing inefficiency.

    Definitely reserving the Tesla Model 'F' and starting to stockpile banana skins... ;)
     
  6. WannabeOwner

    WannabeOwner Active Member

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    Hehehe ... Yup, can't argue with that. But I have no idea whether that is acceptable solution to the Average Millennial?

    Looking at my parent's generation ... they would come here and cook a meal for us ... and the fridge would be full of pots with each individual leftover that, if it were their house, would effortlessly get used up. Wartime spirit applies I expect.

    Passive House is shirt sleeves in the depth of winter. No need for Jumper ... and tiny kW heating fuel.

    I think Millennials could cope with that :)

    Yes, that is SO difficult (and expensive, relatively speaking).

    I am disappointed that e.g. Passive House hasn't become the requirement for new housing stock. Dramatic reduction in Winter illness etc. too - so would improve GDP by reduction in lost-sickdays as well as balance of payments with Oil States. Ho!HuM!

    I think battery-supply is the pinch-point but I look forward to it happening. My mates who are slow to do it are, like us early adopters, going to love driving EV and will then be kicking themselves and saying "Wish I had done this years ago".
     
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  7. darhall993

    darhall993 Member

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    I've been considering the EV Inverter, thanks for the details. How does your Tesla handle it when Solar production dips below the house demand and then returns? I have several hundred kWh per month that I would only get 5 cents/kWh for export but pay 14 cents per kWh, this would help manage exports and only allow them when the car is full
     
  8. Akikiki

    Akikiki A'-Lo-HA ! y'all

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    Sorry, I can't help you understand that. I haven't taken the cable out of the box and used it. I have a different kWh usage situation than you. The terminology the PUC and utility here us is, we sell back and buy back, they don't store for us. Here, I sell back to the utility at about 28-30 cents per. And I am on the utility's EV pilot program. If I charge (or use everything else) after 9 p.m., I buy back at 6 cents less per than I sold to them. So, I am only charging at night. I got the EV inverter because I sort of talked my contractor into supplying it vice the one without (at no additional cost to me). For me the EV inverter becomes a backup charging method in the even I am having an issue with my 50 amp/MC side.
     
  9. Dalphaon

    Dalphaon Member

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    I am still waiting for my Zappi v2 to arrive. Of course you could look out the window and alter your charge rate but you would be running out every 5 minutes when a cloud goes overhead. The Zappi (and Eddi) would automate this. With regards to winter when it is generating less than 1kw, Zappi has an Eco mode that will use all of what you are generating (say 0.5kw) and add 0.5kw from the grid. That way you get to use as much of your generated solar as possible
     
  10. nightowl

    nightowl Member

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    I have 4kW solar PV installed here, along with a Solar iBoost (similar job to an eddi - divert excess energy into immersion heater.) Recently wired it up to do the bottom element as well as the top, as heating the bottom element overnight would cause it to be hot enough that the iBoost would decide not to do anything. Dumping around 6 or 7kWh into it each day generally.

    Considering getting a zappi but that won't work in tandem with the iBoost because both would measure the excess and try to use it for themselves. So I'll probably get an eddi to replace the iBoost since that will work with the zappi and I can use some for car, some for hot water. An added bonus is the eddi doesn't have a fan - the iBoost whirrs away noisily against the airing cupboard wall in summer (right by the bedroom!)
     
  11. Epico

    Epico Member

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    I have a power reducer that does the same with the hot water...I don't think you will have an issue...from everything I've been told the zappi will work with other systems as all you would do (I am no expert at all) is have the car charger be prioritised for the excess. Then when you aren't plugged in it will be just like now.
    Might be worth using the online chat funtion on the myenergi website or I believe there is a myenergi forum you might want to check out
     
  12. Epico

    Epico Member

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    Something I didn't realise until after I'd ordered (not that it would of made a difference) is that the zappi has a 1.4kw minimum it will send to the car. So if you are only generating 500w it would need to pull 900 from the grid...you can change this on the settings to state how much you want to pull from the grid.
    I will set mine to only pull up to 350w from the grid so the cost is the same as the octopus off peak rate for charging (or near as damn it). If it's below that the car won't charge but my water will get heated so it's not going to export to the grid
     
  13. Avendit

    Avendit Member

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    Watching with interest, thanks for all the info and experiences. Along side the M3 that is on order we are also doing the harder 'upgrade your housing stock', (new extension to modern standards, masses of insulation to old part of the house although not trying for pasiv standards, and a ASHP) but haven't plumbed for solar, yet. Figured we are better off buying mass-produced renewables via the right tariff than trying to do much meaningful with our WSW facing roof in Scotland.
     
  14. LukeT

    LukeT Member

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    #34 LukeT, Sep 12, 2019
    Last edited: Sep 12, 2019
    Watching with interest here too. I am holding off on the charger until I do some building work to an outbuilding with a south facing roof. So I plan to have as much PV on that as I can fit. Ideally panels will replace the whole pitch. And we have 2 large hot water tanks and GSHP, so a lot of 45 degree water which can, and in fact needs periodically to, be heated up to 65, storing a fair bit of spare generation. I'm hoping for about 8kw. We're on a 3 phase connection.

    My "Plan A" is to fit a zappi and prioritise it over the immersion, so there should be enough power for the car on a sunny day, if the car's there.

    I'm not sold on a battery at this point. I don't think it adds much if anything to the environmental positive I'm trying to achieve, so it comes down to pure financials and from what I see so far I don't think they stack up. I suppose a variable tariff may change this view.

    A reservation I have is moving away from the "button on plug" tesla charger. Need to try the other connector release methods to know a lack of button won't annoy management.

    I do also have another project coming up which is a retrofit. Reasonably well insulated bungalow in good order but with a knackered oil boiler. I can't fit a fossil fuel boiler in 2019 so looking for alternatives without big investment. One option is to combine PV, battery, electric boiler and variable rate electricity. There's a provider offering a half hourly tarrif based on wholesale prices and a battery system which reacts to that by charging cheap and discharging at expensive times. Needs more work but this also may be the thing which changes my battery view at home.
     
  15. VanillaAir_UK

    VanillaAir_UK Waiting patiently for a tow

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    Possibly a good approach but don't rule out solar just because of aspect. South facing gives best peak output, but that is not necessarily the best option - E/W split roofs for example give good peak but also an extended day.

    If you have not already looked, there are some good sites such as PVGIS JRC Photovoltaic Geographical Information System (PVGIS) - European Commission to give pretty good results even with using the defaults, just setting rough lat/lon via map and installed kWp (initially look at 4) - certainly do not believe a word that an installer tells you without double checking on PVGIS for meaningful range. It does start getting more complex when shadows get involved, even overhead wires - Solar PV hates shadows of any kind, although ways to mitigate against this. Also worth checking on pvoutput.org to see if anyone near you is generating and what sort of power they get at different times of day and season.

    My personal view on likes of Zappi is that you can probably achieve 80% of what it does simply by looking at the weather. This is based on the fact that I want my car to be charged when I need it to be, rather than using up any excess energy instead of passing it on to benefit other grid users - 1kW of power you export is 1kW less coming from marginal source typically gas, less often coal. Once you become a PV user, it becomes second nature to time things when things are likely to be good and not worrying about the odd occasion you don't optimally get under the generation curve. I think the Zappi min export value makes that mode pretty useless for many during the winter months, and even for days like we have been having this week and rest of time, maybe 1-2 days of week car will be sitting charging when sun is shining.
     
  16. LukeT

    LukeT Member

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    Presumably combining a larger PV capacity with a zappi would reduce this concern a very long way? Relative output per kW installed can then be very low and still be enough to beat zappi's minimum.

    In a similar vein, for those who have published their graphs and use excess for an immersion heater, would you not prioritise zappi over immersion when the car is awaiting a charge, leaving the immersion heater to take the power when it isn't? (I'm assuming it's not your only source of water heating.)
     
  17. VanillaAir_UK

    VanillaAir_UK Waiting patiently for a tow

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    Things get less straightforward and potentially complex and very expensive when you start having to ask the DNO for permission to install - I think it’s still 16A single phase (around 4kW of panels allowing for slight derating) although possibly slightly more if you start significantly derating your inverter. Of course some may have 3 phase, so everything is 3x but it’s not common.

    Of course you also need the real estate to mount the panels. They have got more efficient but for common UK housing stock it’s not going to be an option.

    Today not a bad September day weather wise but I still get long periods when a Zappi would not charge in solar mode. I personally would prefer to know my car was charging rather than fight the clouds - if you turned car down to 6A charging I wouldn’t be surprised if that out charged a Zappi at only cost of a few extra penny’s. Come another couple of months, short of a solar farm, it’s going to be like that for pretty much any domestic install.

    As I say. My priorities are knowing that my car will be charged because I need it to be rather than saving the odd penny here and there and not exporting useful energy back for someone else to benefit from. Even with Solar PV, at grid level, for every kW you charge your car from Solar, a marginal power source elsewhere is having to make up for that deficit not flowing back into the grid. Cars really should be charging only when necessary or when the marginal power source is not gas or coal etc - likely overnight by current usage but may change with wider adoption of EVs.

    IMHO
     
  18. S.Badger

    S.Badger New Member

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    I was looking for a way to divert excess solar to the M3 until I realized I didn't need to. I'm charging my car with Solar overnight.....indirectly. Octopus pay me 5p per kWh for export, and charge me 5p per kWh to charge the car between 12 and 4am
     
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  19. Fullerene

    Fullerene Member

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    That's Genius - you have the cheapest and highest capacity battery out there!
     
  20. VanillaAir_UK

    VanillaAir_UK Waiting patiently for a tow

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    Totally agree. Your excess solar has gone to reduce grid reliance on marginal supply (usually gas or coal) and you buy it back (less grid losses) when less likely to have reliance on high carbon marginal sources. Cost 5p kWh. Bargain. No Zappi required.
     

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