Solar panels query

society4

Hi, I’m want to get some panels (8 is all I can fit south facing). My primary purpose is to charge an ev car during the day and save on bills. I don’t really want a battery or hot water. I don’t want to have appliances on at night or charge the car at night either and most of the use is during the day,What is the best thing I should do….. I’ve seen a quote for 8,444 before grant. Also my house is over 4 years old and I’m wondering do they inspect your roof/attic before installation in case bracing is required. One last thing.. I have vents on the roof after getting attic insulation. …is that a problem …will the panels just be placed over the…..thanks

the_amazing_raisin

So to answer your questions in no particular order

-Officially you can't cover the roof vents and won't be eligible for the grant if you do. You'll need to either move the vent or install the panels around it

-Remember there's a minimum 50cm clearance required between the panels and any edge of the roof. But that can be lower for the vents (mine are literally beside them

-The best way to get a good price is to get multiple quotes and see where you land. Having said that, your quote seems a bit on the high side for a no battery system, so I'd advise looking around some more. There's a PV quotes thread you can check for guidance as well

-Most installers do a survey before installation, so ask any questions then. Having said that, a 4 year old house should be fine

-I know your primary purpose is for charging an EV, but it's worth remembering that you can only charge it when you're at home. So if you're out and about and the sun is shining it'll go directly to the grid. In that case, unless you're getting a lot of money from export, a small battery or diverter can be very useful. If you aren't convinced now, you can get the installer to put a hybrid inverter in now so it's easy to hook up a battery later if you decide to. That will add cost though, so make sure you do your sums first

-One other selling point for batteries, you'll need them if you want the possibility of having backup power in a power cut. They're rare but enough of a hassle when they happen to make it worth thinking about. Most backup power setups won't power the whole house, normally just a couple of sockets. It's enough to charge phones, power the internet router and boil the kettle or run an air fryer, which is probably more than your neighbours will have

slave1

Look at your sums, that's a lot of money for very little power for half the year to charge your car and even then you'll need good sunlight for the other six months to basically drip feed your car after covering likes of house/dishwasher/washing machine etc

Calahonda52

Re this:

My primary purpose is to charge an ev car during the day and save on bills.

So when are you going to drive, at night?

or tell the the OH she needs to take the bus if its sunny😎

I see this line of BS being peddled now by PV installers... oh, you have an EV so free charging ......

You are away for a weekend with the OH or whatever and the sun comes out, so you have a guilt complex about not availing of it...

Like the free power for one weekend day: cant go away for a weekend....

WTF

Life is for living

the_amazing_raisin

https://www.boards.ie/discussion/comment/121134860#Comment_121134860

Yeah I've been averaging 65-100% of my driving from solar power the past few months

I had to charge from the grid for the first time this month just last weekend

All detailed here

https://www.boards.ie/discussion/2058294549/im-driving-on-sunshine-whooah

I do agree it only works if the EV is at home most of the time, helps if you're retired or working from home

I don't feel particularly guilty if I end up exporting to the grid. Biggest concern is the bunch of PHEVs around me that could have plugged in while I'm gone

I'll care even less when I get a smart meter and I actually get paid for what I export

I do find on a sunny day that if I'm going for a coffee I might walk instead of taking the car and let it charge up a bit more

the_amazing_raisin

https://www.boards.ie/discussion/comment/121134815#Comment_121134815

I'm guessing the OP has a 24 hour tariff since they don't want to run appliances at night, but I do agree that by focusing on the EV you're forgetting about the more costly daytime usage

For the OP, it's worth considering that typically the day rate of electricity is 2-3 times the night rate. So if you save 1kWh of night usage it's only worth half as much as saving on daytime usage

Do what works for you, but as slave1 said you really need to do your sums to make sure you're maximising the return on investment

graememk

With 8 panels I wouldn't even bother trying to capture it with an ev.

I'd just export it and then buy back on night rate.

Export at 24c but buy back at 20,

@Calahonda52 I have a solution if you want to drive during the day... 2 cars, one to charge and one to drive, and then swap 😜 (tone: sarcasm)

the_amazing_raisin

https://www.boards.ie/discussion/comment/121135056#Comment_121135056

Actually that's a good point, you need 1.4kW to start charging the EV and 8 panels is probably 3.3kWp

Definitely better to focus on the house usage, personally I think if you shop around you could get a 5kWh battery as well for a similar price to what the OP quoted

society4

just to clarify I WFH 3 days per week and can charge the car on those days…. I agree a battery would be a good idea.. can anyone tell me how many km or percentage charge would you get charging it for 8 hours on a sunny day ?

the_amazing_raisin

https://www.boards.ie/discussion/comment/121135392#Comment_121135392

How long is a piece of string 😉

There's a lot of factors, if you're spending the day cooking and doing laundry then there's not going to be a lot going to the car

It's better to take the long view and look at a weekly or monthly basis

For some context, here's the number of "free" kilometres I got for the past 4 months

May - 603km

June - 632km

July - 582km

August - 513km

I'm WFH 5 days a week, I've got a 6kWp array and a 10kWh battery

Just be aware of that 1.4kW minimum charging threshold. For my system, it needs to be at 25% capacity to get there, so I can charge my car on a lot of fairly marginal days

For a 3.3kWp system like yours, you'll need just under 50% so you need a sunnier day to charge the car

Hence why I'm thinking a battery or diverter, or both, would be very useful to you

It's also worth checking what meter types you have. If it's a non smart meter then you get an estimated amount of exported power, so it's best then to export nothing

They are charging everyone over to smart meters though, which will give you measured export amounts. On the plus side, if you dump a load of power to the grid then it isn't a disaster, you'll get paid for it all

allinthehead

https://www.boards.ie/discussion/comment/121135392#Comment_121135392

I have a slightly bigger system than what you're thinking of getting, 12 panels but only 8 are SE facing, two are NW and 2 are W. My peak kw is around 3.4. I have a 60kwh battery in my car and the best I got this summer was 20% over the day.

Fyi I'm planning to add 10 more panels as I'd like to be self sufficient in the better months for charging the car.