Installing Solar panels for the EV
Discussion
Looking for advice on this.
Is it possible (/sensible) to run an EV charger off solar panels, or more likely off a battery that's charged by solar panels (because the sun comes out during the day and the charging is done at night).
Just to clarify I'm thinking of a stand-alone system on/in the garage, i.e. just for the EV, not mixing it with the house electrics.
How much would it cost to install (say 6 panels) and how do I go about it?
My initial Googling says 6 panels can give 2.5Kw, so they should produce at least 10Kwh a day on average.
Is it possible (/sensible) to run an EV charger off solar panels, or more likely off a battery that's charged by solar panels (because the sun comes out during the day and the charging is done at night).
Just to clarify I'm thinking of a stand-alone system on/in the garage, i.e. just for the EV, not mixing it with the house electrics.
How much would it cost to install (say 6 panels) and how do I go about it?
My initial Googling says 6 panels can give 2.5Kw, so they should produce at least 10Kwh a day on average.
It is possible, not very practical but possible.
Solar varies hugely across the year and is very weather dependent. That said my array produced 7MwH each of the last 5 years.
I've got 24 panels, 2 Evs and a house battery.
I used to consume excess electricity (panels producing more than house load) by charging the cars.
Recently I've changed tariff and I now charge cars and battery cheaply overnight and export my solar because its financially beneficial.
Solar varies hugely across the year and is very weather dependent. That said my array produced 7MwH each of the last 5 years.
I've got 24 panels, 2 Evs and a house battery.
I used to consume excess electricity (panels producing more than house load) by charging the cars.
Recently I've changed tariff and I now charge cars and battery cheaply overnight and export my solar because its financially beneficial.
The power electrics of it are not hard, it's fairly well trodden ground to have solar panels, batteries, inverters.
The 'software' side of it, whether your EV will happily charge off a limited power inverter, what happens when there's not enough in the house battery to charge the EV, how you switch it over to charge from the mains.... Do you want all that to happen automatically, or are you adopting 'battery managment' as a major hobby?
It will be much easier to know that everything works if it's connected to the grid. Loads of people are doing that, it's common tech which is bringing costs down, compared to off-grid which is small market expensive.
I do know someone who has been driving a PHEV for 5 or 6 years, frequently charging it from solar, as far as I know, he'd tell you it was a good wheeze when he started, because the export tariff was low or effectively zero, these days the world has changed. I think the world of tariffs will continue to evolve, so personally I would not rush into anything with a long payback.
For sure, there is a world of 'offgrid' where you can DIY and avoid costs of compliance etc, I know people with solar and inverters etc on yachts for instance.
The killer is probably that the 'average' yield is no help in a rainy week in February.
Have look at this:
http://www.newquayweather.com/wxsolarpv.php
From the second to the 8th of this month, 17kWh from a 3.6kW system in a whole week.
That's about 50 miles of EV driving?
The 'software' side of it, whether your EV will happily charge off a limited power inverter, what happens when there's not enough in the house battery to charge the EV, how you switch it over to charge from the mains.... Do you want all that to happen automatically, or are you adopting 'battery managment' as a major hobby?
It will be much easier to know that everything works if it's connected to the grid. Loads of people are doing that, it's common tech which is bringing costs down, compared to off-grid which is small market expensive.
I do know someone who has been driving a PHEV for 5 or 6 years, frequently charging it from solar, as far as I know, he'd tell you it was a good wheeze when he started, because the export tariff was low or effectively zero, these days the world has changed. I think the world of tariffs will continue to evolve, so personally I would not rush into anything with a long payback.
For sure, there is a world of 'offgrid' where you can DIY and avoid costs of compliance etc, I know people with solar and inverters etc on yachts for instance.
The killer is probably that the 'average' yield is no help in a rainy week in February.
Have look at this:
http://www.newquayweather.com/wxsolarpv.php
From the second to the 8th of this month, 17kWh from a 3.6kW system in a whole week.
That's about 50 miles of EV driving?
M4cruiser said:
Is it possible (/sensible) to run an EV charger off solar panels, or more likely off a battery that's charged by solar panels (because the sun comes out during the day and the charging is done at night).
Possible - yes, sensible - no.When it will cost you as little as 7.5p/kWh to charge the car then the cost of the panels is going to have to be damn cheap to beat that - and they are not.
And then the sun doesn't shine every day so you would either need to have expensive batteries to store that expensive 'free' solar electricity, or charge from the mains.
The maths makes no sense for most people, and the only people it does are those who got the systems installed years ago when the government was paying them to do so, those who get it installed at a non-commercial rate, or those who ignore the investment value of the money that was spent on the installation.
dmsims said:
Let's just quantify that:
6 panels £480
5kWh batteries are a £grand lets say 2
Victron 3000VA with GX £660
Cabling, switches etc £300
Total: £3440
Plus labour - not everyone can fit and wire up stuff like that.6 panels £480
5kWh batteries are a £grand lets say 2
Victron 3000VA with GX £660
Cabling, switches etc £300
Total: £3440
sfella said:
I doubt you'd get your outlay back in saved pennies any time soon, panels and battery we we're being quoted teens of thousands
Some quite intelligent (but non-scientific) friends of mine thought they might be able to power an EV with a solar panel on its roof... idealism fails when you realise how relatively little power a solar panel makes, how much power an EV needs, and the fact the sun goes in.
dmsims said:
So, with the Op's wheeze to DIY it, £3500 or so.
Most EV owners are getting mains power for about 10p/kwh,3 or 4 p per mile, so, the payback might be 100,000 miles, bearing in mind that the kWh of sunlight won't always arrive at the right time.
OutInTheShed said:
The materials may be £4k or so, but most people need white van man to install it.
So, with the Op's wheeze to DIY it, £3500 or so.
Most EV owners are getting mains power for about 10p/kwh,3 or 4 p per mile, so, the payback might be 100,000 miles, bearing in mind that the kWh of sunlight won't always arrive at the right time.
Yep, as a Nissan Leaf owner I've done the maths on this, wanted it to work, but it doesn't get to within an order of magnitude. I think I came up with around £3k to do a reasonable installation but I am currently paying 9p/kwh to charge for four hours every night via Octopus energy.So, with the Op's wheeze to DIY it, £3500 or so.
Most EV owners are getting mains power for about 10p/kwh,3 or 4 p per mile, so, the payback might be 100,000 miles, bearing in mind that the kWh of sunlight won't always arrive at the right time.
£3k buys 33,000 kw/hours of charging, equivalent to 23 years of four hours per night (easily enough for our needs).
There are of course a number of variables, but broadly speaking it doesn't work financially.
Edit - Forget that lot, got my maths a bit wrong. A bit late now for me to redo the sums, but in summary, I don't charge the Leaf for four hours every night, but it pulls 3.5kw. Roughly speaking £3k covers the cost of eight years of charging for our usage.
Edited by Turtle Shed on Saturday 10th February 22:19
It's actually cheaper to export to the grid from the solar panels than it is to charge the car. Octopus gives 15p/kWh exported but you can charge at 7.5p/kWh.
I bought a Solar/Givenergy battery/Zappi system and initially charged the house battery and then car from solar, but when Octopus increased their export rate, I now just charge the home battery to 100% every night and so any excess solar is exported.
I bought a Solar/Givenergy battery/Zappi system and initially charged the house battery and then car from solar, but when Octopus increased their export rate, I now just charge the home battery to 100% every night and so any excess solar is exported.
dmsims said:
Let's just quantify that:
6 panels £480
5kWh batteries are a £grand lets say 2
Victron 3000VA with GX £660
Cabling, switches etc £300
Total: £3440
6 panels £480
5kWh batteries are a £grand lets say 2
Victron 3000VA with GX £660
Cabling, switches etc £300
Total: £3440
PF62 said:
The maths makes no sense for most people, and the only people it does are those …who get it installed at a non-commercial rate, or those who ignore the investment value of the money that was spent on the installation.
Bingo Thinking the bigger picture here about how home energy storage / EVs could be used to balance grid demand.
Biggest problems of decarbonsising energy is the national grid and minimal electricity storage for the intermittency of renewables - particularly solar pv.
There is 4.1% of uk households with Solar PV, 1,2 million homes.
Imagine if one million solar homes had decent battery storage, all charging cheap rate overnight in the small hours and exporting back at peak rate.
This, plus a million EVs in uk using their cars for battery storage just as much as a transport vehicle.
Also many EVs inner city, just where the maxxed out local grid could use the extra juice at peak times.
Could this energy storage / grid balancing benefits actually outweigh just the solar PV electric generation?
Should domestic battery storage be more incentivised, and would this be a good use of green funding?
Would potential home investors be better to wait until the peak / off peak arbitrage becomes more generous?
One thing is for certain: energy will continue to get more expensive.
Biggest problems of decarbonsising energy is the national grid and minimal electricity storage for the intermittency of renewables - particularly solar pv.
There is 4.1% of uk households with Solar PV, 1,2 million homes.
Imagine if one million solar homes had decent battery storage, all charging cheap rate overnight in the small hours and exporting back at peak rate.
This, plus a million EVs in uk using their cars for battery storage just as much as a transport vehicle.
Also many EVs inner city, just where the maxxed out local grid could use the extra juice at peak times.
Could this energy storage / grid balancing benefits actually outweigh just the solar PV electric generation?
Should domestic battery storage be more incentivised, and would this be a good use of green funding?
Would potential home investors be better to wait until the peak / off peak arbitrage becomes more generous?
One thing is for certain: energy will continue to get more expensive.
Edited by Tyrell Corp on Sunday 11th February 10:10
pacenotes said:
Why wouldn’t you connect it to the house?
It’s the same amount of equipment so no cost difference.
Many have explained why it makes no sense to do what you ask, OP…It’s the same amount of equipment so no cost difference.
….but also this ^^^^
Why not connect to the house?
What is your logic for asking?
Batteries are broadly hopeless for EV charging….many EVs have 60-80kWh batteries.
Most home batteries are around 5-10kWh. Sure, you can get more - we have 14.4, but rarely would get have bigger than 20kWh.
EV charging needs to be on cheap rate overnight tariffs for maximum benefit.
Tyrell Corp said:
Thinking the bigger picture here about how home energy storage / EVs could be used to balance grid demand.
Biggest problems of decarbonsising energy is the national grid and minimal electricity storage for the intermittency of renewables - particularly solar pv.
There is 4.1% of uk households with Solar PV, 1,2 million homes.
Imagine if one million solar homes had decent battery storage, all charging cheap rate overnight in the small hours and exporting back at peak rate.
This, plus a million EVs in uk using their cars for battery storage just as much as a transport vehicle.
Also many EVs inner city, just where the maxxed out local grid could use the extra juice at peak times.
Could this energy storage / grid balancing benefits actually outweigh just the solar PV electric generation?
Should domestic battery storage be more incentivised, and would this be a good use of green funding?
Would potential home investors be better to wait until the peak / off peak arbitrage becomes more generous?
One thing is for certain: energy will continue to get more expensive.
Batteries are getting cheaper.Biggest problems of decarbonsising energy is the national grid and minimal electricity storage for the intermittency of renewables - particularly solar pv.
There is 4.1% of uk households with Solar PV, 1,2 million homes.
Imagine if one million solar homes had decent battery storage, all charging cheap rate overnight in the small hours and exporting back at peak rate.
This, plus a million EVs in uk using their cars for battery storage just as much as a transport vehicle.
Also many EVs inner city, just where the maxxed out local grid could use the extra juice at peak times.
Could this energy storage / grid balancing benefits actually outweigh just the solar PV electric generation?
Should domestic battery storage be more incentivised, and would this be a good use of green funding?
Would potential home investors be better to wait until the peak / off peak arbitrage becomes more generous?
One thing is for certain: energy will continue to get more expensive.
Edited by Tyrell Corp on Sunday 11th February 10:10
The LifePO4 cells favourred for home battereis and some cars, due to their long 'cycle life', are below $100 per kWh at the factory gate in bulk.
Production is increasing exponentially.
I think this means it's just a matter of time before commercial operators use batteries to level out demand across the day.
I think this will mean the difference between peak and off-peak electricity prices will be much, much smaller.
Solar panels are also very cheap now esily found below £100 retail for 400W or so.
(annoyingly dearer per watt for the ones which will fit on my boat! cest la vie!)
Builders are still throwing up houses with no solar, but more solar is being installed.
Around here, farmers are putting up a row or two if not a field, barn rooves are being covered, etc etc.
Ifyou look at gridwatch, right now, in winter, Solar is providing 9% of demand.
To be fair it's a nice day down here, good sailing breeze, (I ache now!) not obvious why wind is only doing 12%, but I digress!
I think the economy 7 mindset is for the chop. Cheap night rate is probably being artificially propped up now, to encourage EVs, smartmeters and to get homeowners to spend.
Within a few years, the complex 'agile' pricing will be the norm. Octopus will charge everyone's car minute by minute overnight at varying rates to suit them and to minimise the need for gas power stations.
The killer with solar panels at home is paying about £8k in labour for some oiks to damage your roof.
Hence I do understand where the OP is coming from.
Thank you for all the replies.
It seems that the upfront costs would take a long time to recover. We are spending about £500 a year charging the car. My understanding is that the system would degrade as well, so I would need to replace panels and batteries after about 20 years.
A 10Kwh battery would suffice, as it would unload itself into the car every couple of days, giving a partial charge to the car's battery. Provided the system can sustain a 240v 10A supply, like a normal 3-pin socket/plug. I get that batteries are not 100% efficient, so some of the solar energy wouldn't make it into the car, but that wouldn't matter if it was free.
To explain why it would be a separate system, the house doesn't face south, the pitched roofs are facing east/west, so not ideal for an installation. However, the garage faces south! But isn't big enough for enough panels to provide significant power to the domestic installations. We could put all the power generated by the solar into the car, so there seems little point in complicating the installation for no benefit.
It seems that the upfront costs would take a long time to recover. We are spending about £500 a year charging the car. My understanding is that the system would degrade as well, so I would need to replace panels and batteries after about 20 years.
A 10Kwh battery would suffice, as it would unload itself into the car every couple of days, giving a partial charge to the car's battery. Provided the system can sustain a 240v 10A supply, like a normal 3-pin socket/plug. I get that batteries are not 100% efficient, so some of the solar energy wouldn't make it into the car, but that wouldn't matter if it was free.
To explain why it would be a separate system, the house doesn't face south, the pitched roofs are facing east/west, so not ideal for an installation. However, the garage faces south! But isn't big enough for enough panels to provide significant power to the domestic installations. We could put all the power generated by the solar into the car, so there seems little point in complicating the installation for no benefit.
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