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Small roof advice needed

  • 07-03-2023 10:29am
    Registered Users Posts: 1,931 ✭✭✭

    Looking at solar PV but my roofing situation is poor. Velux windows etc.

    Have had a look (thankfully OH is an arch tech) and maximum panels I can fit is 5 x 410w on a south facing roof. Could fit 4 more on a Easterly roof but unsure if they'll produce much.

    Have a new EV with vehicle to load and the ability to charge in work for free. Was hoping to have a battery system running off that and the solar.

    Complete newbie at the solar.

    All suggestions welcome.



  • Registered Users Posts: 1,402 ✭✭✭DC999

    I’ve a similar roof. I’d suggest max out South to produce the most (and might need optimisers for panels shaded by the velux, if it’s summer shading. Don’t optimise for winter shading as output it low). Or more the source of shading if possible. I got installer to cut the drain vents to just above gutter height to prevent shading. Took maybe 2 foot off them. See if you’ve old pics of the roof to see how the shadows are cast.

    And then max out East. I’ve 2 East roofs, one is a flat kitchen extension. Output is very solid. E or W will never match South output, but you work with the roof you have. I’ve 2.7kWp East panels and they produced 1000kWh since it went live at end of July last year. And that excludes from March onwards where the output will climb. Aug and Sept are decent, them it drops to around now and stars to climb again.

    East gives morning sun and in summer it’s still producing something to ~4pm. But output drops as the day goes on as the sun moves around the house. W is evening sun.

    Can’t answer the vehicle to load (V2L) Q – don’t know about that. You won’t typically charge your EV from a smaller house battery. Would suffer electrical losses on both batteries, so not worth it. Will occasionally when need a boost of course. Have a think if a house battery is a benefit to you if the car has V2L and is in the driveway a lot (needs to be of course). But park that for now and look at the solar side first, you don’t need to get bogged down in the V2L options immediately until you are ready to get solar quotes. 

  • Registered Users Posts: 6,805 ✭✭✭Alkers

    Is your car typically home during the day?

    Free work charging & vehicle to load, run your house off the car every night amd stay on a 24hr tarrif with solar panels saving on daytime use.

  • Registered Users Posts: 1,931 ✭✭✭ewj1978

    car is home 4 days out of eight. I was toying with the battery option only and just coming home sticking 20kwh into the battery and running the house for free for 3 days or just topping it up and running for free..

  • Registered Users Posts: 1,402 ✭✭✭DC999

    Can you run the house now on your V2L already? And what charger does that? My Leaf has V2L but Zappi won’t allow if to feed the house.

    I don’t have a house battery so could use the car for that in time. Curious now myself. 

  • Registered Users Posts: 1,931 ✭✭✭ewj1978

    No, I can't at the moment. Don't have the technical knowledge to do it. Tbh not even sure where to start

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  • Registered Users Posts: 1,013 ✭✭✭sh81722

    Nissan's V2G is CHAdeMO based, the equipment is prohibitively expensive unless subsidised like the pilot program that happened in UK and is technological dead end when you change the vehicle. Unfortunate but true. But you can still use the Leaf to soak up the energy from solar for driving.