Solar Charging our EV
Discussion
Just doing some rough costings but a little confused with kWh and KW with regard to storage and generation.
The breif
Our e-niro does 40 miles a day, over 5 days, which means it can be charged over the weekend as it's not used Sat & Sun.
I'd like to charge via solar, at the weekend.
My thoughts are, as we can leave it plugged in both saturday and sunday.
My question is, with a 4kWh solar set up, how long would it take to charge the e-niros 64kWh pack? 16 hours? as simple as 64/4 ?
and... obviously there are big differences between summer and winter but what kind of generation should i expect during a typical weekend ? 6hrs of usable sunlight per day? so 24kwh x2 = 48kwh over a weekend ... ie, not enough?
first off - are my rough pub maths right?
Secondly, what are my options for a full battery? - Powerwall to fill up during weekdays to top up the weekend generated? Larger system (not sure i have the room for that...)
There doesn't seem a way to make this cost effective either - we pay around £60 a month for the EV charging electric, rough sums based on a £6k system, the ROI would be 8 years - that's before we factor in the powerwall/storage.
Have i got this all wrong?
The breif
Our e-niro does 40 miles a day, over 5 days, which means it can be charged over the weekend as it's not used Sat & Sun.
I'd like to charge via solar, at the weekend.
My thoughts are, as we can leave it plugged in both saturday and sunday.
My question is, with a 4kWh solar set up, how long would it take to charge the e-niros 64kWh pack? 16 hours? as simple as 64/4 ?
and... obviously there are big differences between summer and winter but what kind of generation should i expect during a typical weekend ? 6hrs of usable sunlight per day? so 24kwh x2 = 48kwh over a weekend ... ie, not enough?
first off - are my rough pub maths right?
Secondly, what are my options for a full battery? - Powerwall to fill up during weekdays to top up the weekend generated? Larger system (not sure i have the room for that...)
There doesn't seem a way to make this cost effective either - we pay around £60 a month for the EV charging electric, rough sums based on a £6k system, the ROI would be 8 years - that's before we factor in the powerwall/storage.
Have i got this all wrong?
With a water analogy, kW is the size of the pipe, kWh is how much water. Something using 1kW of power for 1 hour uses 1kWh.
4kW array means that best case it'll be producing 4kW. An hour of that means 4kWh into your battery (minus some losses). Apparently a 4kW system in the UK should generate around 3400kWh over a year so could just about cover your usage if you're able to store it - if you're only using 2 days of that it'd be 971kWh or less than 19kWh a week.
Battery storage is the way to go if you did want to generate and use that power during the week, but even more upfront cost. A few weeks of grim weather in winter could still leave you without enough solar energy stored to keep the car going.
Assuming you switch to an EV tariff with a 5p/kWh rate overnight you'd only pay £173pa for the electricity going into the car. You'd probably have to plug in a couple of times over the week to get enough in the cheap window though.
4kW array means that best case it'll be producing 4kW. An hour of that means 4kWh into your battery (minus some losses). Apparently a 4kW system in the UK should generate around 3400kWh over a year so could just about cover your usage if you're able to store it - if you're only using 2 days of that it'd be 971kWh or less than 19kWh a week.
Battery storage is the way to go if you did want to generate and use that power during the week, but even more upfront cost. A few weeks of grim weather in winter could still leave you without enough solar energy stored to keep the car going.
Assuming you switch to an EV tariff with a 5p/kWh rate overnight you'd only pay £173pa for the electricity going into the car. You'd probably have to plug in a couple of times over the week to get enough in the cheap window though.
Edited by sjg on Tuesday 7th September 16:23
You wouldn't get 4KW feed from a 4KW setup more like 3.6KW in ideal positions and clear sky. Winter has massive effect but so does just clouds.
We have a split SW/SE facing 4KW setup, the max I see in the hight of summer is 2.5KW peak. Over the year this is what our solar generation looks like verus house hold usage (including charging the EV).
Charging the PowerWall overnight using cheaper electricity helps reduce over all costs. Our electricity bill is never that expensive even in winter, its the gas bill that I really notice especially between Dec - Feb.
Looking at figure 3500kWh at a night rate of 9p per kWh is under £30/month. Even this year with night rates going up to 15p is going to be just over £40/month, really nothing to waste time/effort on interms of maximising solar/traiff to try and save £5-10/month on electricity.
We have a split SW/SE facing 4KW setup, the max I see in the hight of summer is 2.5KW peak. Over the year this is what our solar generation looks like verus house hold usage (including charging the EV).
Charging the PowerWall overnight using cheaper electricity helps reduce over all costs. Our electricity bill is never that expensive even in winter, its the gas bill that I really notice especially between Dec - Feb.
Looking at figure 3500kWh at a night rate of 9p per kWh is under £30/month. Even this year with night rates going up to 15p is going to be just over £40/month, really nothing to waste time/effort on interms of maximising solar/traiff to try and save £5-10/month on electricity.
Edited by gangzoom on Tuesday 7th September 16:49
I have 8Kw of solar installed and I don’t charge my car with anymore with it.
I export all surplus over house use on Octopus Agile Outgoing and then charge the car at night using Octopus Go.
Export rates averaged 12p/ KWh last month and I import at 5p KWh whenever the car needs a top up.
I export all surplus over house use on Octopus Agile Outgoing and then charge the car at night using Octopus Go.
Export rates averaged 12p/ KWh last month and I import at 5p KWh whenever the car needs a top up.
springfan62 said:
I have 8Kw of solar installed and I don’t charge my car with anymore with it.
I export all surplus over house use on Octopus Agile Outgoing and then charge the car at night using Octopus Go.
Export rates averaged 12p/ KWh last month and I import at 5p KWh whenever the car needs a top up.
Not criticizing and good for you, but the economics of that dont make sense to anyone other than you.... I export all surplus over house use on Octopus Agile Outgoing and then charge the car at night using Octopus Go.
Export rates averaged 12p/ KWh last month and I import at 5p KWh whenever the car needs a top up.
You can make more money selling it out than using what you generate? Madness, but while it works, make that hay!
Well they do actually because it makes pv a viable investment for anyone, the returns are far greater than if you try and use all your own generation.
So actually it’s useful for any who has pv or is considering getting one to charge their ev or to offset their ev usage.
Same goes for anyone using pv to heat their hot water.
So actually it’s useful for any who has pv or is considering getting one to charge their ev or to offset their ev usage.
Same goes for anyone using pv to heat their hot water.
off_again said:
Not criticizing and good for you, but the economics of that dont make sense to anyone other than you....
You can make more money selling it out than using what you generate? Madness, but while it works, make that hay!
Adding electricity to the grid during peak demand and then taking some back during low demand seems far from madness. It’s pretty much the model of the Gridserve electric forecourt in Essex. You can make more money selling it out than using what you generate? Madness, but while it works, make that hay!
Really cool.
off_again said:
Not criticizing and good for you, but the economics of that dont make sense to anyone other than you....
You can make more money selling it out than using what you generate? Madness, but while it works, make that hay!
Yeah some poor souls are still on Octopus AgileYou can make more money selling it out than using what you generate? Madness, but while it works, make that hay!
https://twitter.com/energystatsuk/status/143527345...
35p per KW at peak times.
Octopus buying at 12p and selling at 35p.
springfan62 said:
I have 8Kw of solar installed and I don’t charge my car with anymore with it.
I export all surplus over house use on Octopus Agile Outgoing and then charge the car at night using Octopus Go.
Export rates averaged 12p/ KWh last month and I import at 5p KWh whenever the car needs a top up.
How do you manage that?I export all surplus over house use on Octopus Agile Outgoing and then charge the car at night using Octopus Go.
Export rates averaged 12p/ KWh last month and I import at 5p KWh whenever the car needs a top up.
"Currently, you can't be on both Outgoing Octopus AND Octopus Go, our electricity consumption tariff designed for electric vehicle drivers – but any other consumption tariff is fine. We've made this decision because both are such incredibly good value tariffs that it would be unsustainable for us as a business – the equivalent of letting people buying goods in a shop using a "3 for 2" offer and then bringing them back for a full price refund!"
According to Octopus, Go & Agile Export is not something they offer
That interesting as they have emailed me to confirm the transfer is in progress but they are having a problem finalising my current bill.
It will be interesting to see if they allow it. I think they should actually encourage load shifting.
They also told me that when I went on to outgoing they would stop the deemed export payment as part of my FIT but they haven't, even after I queried it with them.
I think a lot of their staff lack knowledge and their products are more complex than other suppliers.
It will be interesting to see if they allow it. I think they should actually encourage load shifting.
They also told me that when I went on to outgoing they would stop the deemed export payment as part of my FIT but they haven't, even after I queried it with them.
I think a lot of their staff lack knowledge and their products are more complex than other suppliers.
springfan62 said:
I have 8Kw of solar installed and I don’t charge my car with anymore with it.
I export all surplus over house use on Octopus Agile Outgoing and then charge the car at night using Octopus Go.
Export rates averaged 12p/ KWh last month and I import at 5p KWh whenever the car needs a top up.
I didn't realise export rates could be that high! My solar is from the latter days of the FIT & I think i'm paid something like 5.5p/KWh for every unit generated & half that on top for assumed export (but will have to check details). I was under the impression the current export rates were much worse than the FIT ever was.I export all surplus over house use on Octopus Agile Outgoing and then charge the car at night using Octopus Go.
Export rates averaged 12p/ KWh last month and I import at 5p KWh whenever the car needs a top up.
As others have said, trying to charge an EV from solar panels is a waste of time - the sums just don't work out.
This is NZ, so things are a bit different - I get paid 4p per kWhr for the solar, and pay 5p to charge at night - which works for me.
The big difference here is the 5p night rate is from 9pm to 7am.
And yes - a 4kW array will produce about 3.5kW at absolute maximum for only an hour or two on the best days in summer. Winter peak will not be much over 1kW.
Ok, i think everyone has just confirmed my worst fears (ok, maybe that is a little OTT) .. the utopia of being completely net zero cost for fuel isn't possible without significant long term investment.
We are currently with OVO and their 'EV' tariff (which got us a free 7kw charge point supplied and installed) which is, thank god, coming to an end in October. We took this deal before the likes of Octopus and bulb were common knowledge and have been stuck paying 12p/kwh on cheap rate.
The obvious answer is, switch to Octopus with their 4p/kWh night window, set the charging times for 12am-4am and just plug the car in every night
Should halve our EV electric costs.
Thanks for everyone for input.
We are currently with OVO and their 'EV' tariff (which got us a free 7kw charge point supplied and installed) which is, thank god, coming to an end in October. We took this deal before the likes of Octopus and bulb were common knowledge and have been stuck paying 12p/kwh on cheap rate.
The obvious answer is, switch to Octopus with their 4p/kWh night window, set the charging times for 12am-4am and just plug the car in every night
Should halve our EV electric costs.
Thanks for everyone for input.
Pixelpeep 135 said:
Ok, i think everyone has just confirmed my worst fears (ok, maybe that is a little OTT) .. the utopia of being completely net zero cost for fuel isn't possible without significant long term investment.
We are currently with OVO and their 'EV' tariff (which got us a free 7kw charge point supplied and installed) which is, thank god, coming to an end in October. We took this deal before the likes of Octopus and bulb were common knowledge and have been stuck paying 12p/kwh on cheap rate.
The obvious answer is, switch to Octopus with their 4p/kWh night window, set the charging times for 12am-4am and just plug the car in every night
Should halve our EV electric costs.
Thanks for everyone for input.
That's exactly what we've done. We are currently with OVO and their 'EV' tariff (which got us a free 7kw charge point supplied and installed) which is, thank god, coming to an end in October. We took this deal before the likes of Octopus and bulb were common knowledge and have been stuck paying 12p/kwh on cheap rate.
The obvious answer is, switch to Octopus with their 4p/kWh night window, set the charging times for 12am-4am and just plug the car in every night
Should halve our EV electric costs.
Thanks for everyone for input.
We have a 5.6Kw array and a Tesla Powerwall. The car is plugged-in all the time to take whatever surplus is around in the day (there's also a smart immersion heater which takes priority) and fill the car in the middle of the night at 5p.
Pixelpeep 135 said:
Ok, i think everyone has just confirmed my worst fears (ok, maybe that is a little OTT) .. the utopia of being completely net zero cost for fuel isn't possible without significant long term investment.
We are currently with OVO and their 'EV' tariff (which got us a free 7kw charge point supplied and installed) which is, thank god, coming to an end in October. We took this deal before the likes of Octopus and bulb were common knowledge and have been stuck paying 12p/kwh on cheap rate.
The obvious answer is, switch to Octopus with their 4p/kWh night window, set the charging times for 12am-4am and just plug the car in every night
Should halve our EV electric costs.
Thanks for everyone for input.
I have a 4.3kW array, and yesterday, which was sunny all day, I managed to generate 21kWh, putting 8kWh into the home battery and 13kWh into the Kona which should give me about 60 miles.We are currently with OVO and their 'EV' tariff (which got us a free 7kw charge point supplied and installed) which is, thank god, coming to an end in October. We took this deal before the likes of Octopus and bulb were common knowledge and have been stuck paying 12p/kwh on cheap rate.
The obvious answer is, switch to Octopus with their 4p/kWh night window, set the charging times for 12am-4am and just plug the car in every night
Should halve our EV electric costs.
Thanks for everyone for input.
I think you should view solar as a free top-up, but have Octopus Go as your main charging source. It is 5p/kWh from 00:30 - 04:30 so can provide 4 x 7kW = 28kWh during the night for £1.40
NugentS said:
springfan62 said:
I have 8Kw of solar installed and I don’t charge my car with anymore with it.
I export all surplus over house use on Octopus Agile Outgoing and then charge the car at night using Octopus Go.
Export rates averaged 12p/ KWh last month and I import at 5p KWh whenever the car needs a top up.
How do you manage that?I export all surplus over house use on Octopus Agile Outgoing and then charge the car at night using Octopus Go.
Export rates averaged 12p/ KWh last month and I import at 5p KWh whenever the car needs a top up.
"Currently, you can't be on both Outgoing Octopus AND Octopus Go, our electricity consumption tariff designed for electric vehicle drivers – but any other consumption tariff is fine. We've made this decision because both are such incredibly good value tariffs that it would be unsustainable for us as a business – the equivalent of letting people buying goods in a shop using a "3 for 2" offer and then bringing them back for a full price refund!"
According to Octopus, Go & Agile Export is not something they offer
I export my solar at 5.5p and charge my car at 5p on Go.
I joined at the start of their export SEG offering, they closed the door to outgoing and importing later and have never asked me to change from it.
They effectively pay me to charge my car.
I charge from solar when I can but typically it'll be cloudy when I'm not using the car, your PV system will not often perform at its best simply due to the weather. You are expecting it to be sunny all weekend, which is unlikely.
I often expect to buy in 20-50% of car charging power even in the summer, I get barely enough solar from Nov-Feb to run the house baseload, still it's better than nothing.
I only have a small EV battery, if I had (and may even get) an E-nero, then I'll do a variable tariff and charge it on the nights the price is lowest and keep the solar as bonus.
I couldn't make the sums work on a domestic battery. I even struggled with the sheer economics of getting an EV, (the cheapest car to run is a reliable shed) but I feel good about it and it makes a boring commute tolerable.
I often expect to buy in 20-50% of car charging power even in the summer, I get barely enough solar from Nov-Feb to run the house baseload, still it's better than nothing.
I only have a small EV battery, if I had (and may even get) an E-nero, then I'll do a variable tariff and charge it on the nights the price is lowest and keep the solar as bonus.
I couldn't make the sums work on a domestic battery. I even struggled with the sheer economics of getting an EV, (the cheapest car to run is a reliable shed) but I feel good about it and it makes a boring commute tolerable.
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