Stupid question
Discussion
So I often have hairbrained ideas that are great in theory but terrible in real life.
Could you buy a cheap Nissan Leaf or similar and use it as a literal battery to run your home during the day? Charge at night and have it plumbed into your house electrics through the day? Does that work, problems, costs, worth it?
Could you buy a cheap Nissan Leaf or similar and use it as a literal battery to run your home during the day? Charge at night and have it plumbed into your house electrics through the day? Does that work, problems, costs, worth it?
Not a daft idea at all, it exists:
https://www.indra.co.uk/vehicle-to-grid-charger
Not available commercially but has been trialled for the last two or three years. Not sure about costs, I was on the trial so it was free!
https://www.indra.co.uk/vehicle-to-grid-charger
Not available commercially but has been trialled for the last two or three years. Not sure about costs, I was on the trial so it was free!
SimpleSimonSays said:
Not a daft idea at all, it exists:
https://www.indra.co.uk/vehicle-to-grid-charger
Not available commercially but has been trialled for the last two or three years. Not sure about costs, I was on the trial so it was free!
Exactly this.https://www.indra.co.uk/vehicle-to-grid-charger
Not available commercially but has been trialled for the last two or three years. Not sure about costs, I was on the trial so it was free!
The Leaf uses the Chademo standard which has always allowed Vehicle to Grid (V2G, or sometimes Vehicle to Home V2H). But the home hardware has been unavailable and expensive (I believe about £5k). In the UK, it hasn't widely received approval from the electricity companies.
The more popular CCS charging standard is due to finalise their V2G/V2H standard early this year. It's long overdue. And no idea yet on whether the millions of existing electric cars will be backwards compatible or how expensive the home-side equipment will be.
Ford have already announced the Ford F150 will have a capability. And several cars now have V2L (ability to plug an extension cable in). It's matching the grid frequency that is the important part.
I won't be buying home batteries because they seem pointless if I have 40-100kWh sat on my driveway during the day.
You could perhaps buy a Leaf, strip the battery out, then wire it up to an inverter of the type used for solar panels to power the house.
The thing is, at best you're going to save maybe £2 a day by doing so and the whole installation would probably cost you at least £10k, so that's a 10+ year pay-back period and in 10 years time EVs will probably be common enough that the concept of "cheap" overnight electricity has vanished anyway.
The thing is, at best you're going to save maybe £2 a day by doing so and the whole installation would probably cost you at least £10k, so that's a 10+ year pay-back period and in 10 years time EVs will probably be common enough that the concept of "cheap" overnight electricity has vanished anyway.
Evanivitch said:
It's matching the grid frequency that is the important part.
Which is not inherently particularly difficult, especially if you're starting with smooth DC. As far as I can see you basically just need a damned great PLL, the same thing that is used for synchronising clock signals across multiple generation domains in electronics, feeding the clock into your inverter? I guess it'd be complicated slightly by the fact that different countries have different mains frequencies. Edited by kambites on Tuesday 25th January 20:58
kambites said:
You could perhaps buy a Leaf, strip the battery out, then wire it up to an inverter of the type used for solar panels to power the house.
The thing is, at best you're going to save maybe £2 a day by doing so and the whole installation would probably cost you at least £10k, so that's a 10+ year pay-back period and in 10 years time EVs will probably be common enough that the concept of "cheap" overnight electricity has vanished anyway.
What if work allow free charging, drive home and run the house?The thing is, at best you're going to save maybe £2 a day by doing so and the whole installation would probably cost you at least £10k, so that's a 10+ year pay-back period and in 10 years time EVs will probably be common enough that the concept of "cheap" overnight electricity has vanished anyway.
kambites said:
You could perhaps buy a Leaf, strip the battery out, then wire it up to an inverter of the type used for solar panels to power the house.
The thing is, at best you're going to save maybe £2 a day by doing so and the whole installation would probably cost you at least £10k, so that's a 10+ year pay-back period and in 10 years time EVs will probably be common enough that the concept of "cheap" overnight electricity has vanished anyway.
Do the maths again at 20p/kWh and 30p/kWh and it starts to make financial sense a lot sooner. The add electric heating (heat pump or otherwise), and suddenly your electrical demand is huge.The thing is, at best you're going to save maybe £2 a day by doing so and the whole installation would probably cost you at least £10k, so that's a 10+ year pay-back period and in 10 years time EVs will probably be common enough that the concept of "cheap" overnight electricity has vanished anyway.
But paying £500-1000 a kWh storage at the moment is pointless when a 60kWh car is £25,000.
SimpleSimonSays said:
Not a daft idea at all, it exists:
https://www.indra.co.uk/vehicle-to-grid-charger
Not available commercially but has been trialled for the last two or three years. Not sure about costs, I was on the trial so it was free!
Doesn't just have to be vehicle to grid either. Once a cell pack is too degraded for EV use, it can be removed and re-purposed as a home energy store. So 2 or 3 old leaf batteries that are hopelessly degraded in terms of powering an EV, could quite happily sit in a stack and power a house.https://www.indra.co.uk/vehicle-to-grid-charger
Not available commercially but has been trialled for the last two or three years. Not sure about costs, I was on the trial so it was free!
Only trials and flaky start-up solutions at the moment, but it'll become more mainstream as the supply of retired EV batteries increases I have no doubt.
Evanivitch said:
Do the maths again at 20p/kWh and 30p/kWh and it starts to make financial sense a lot sooner.
I was assuming about 25p/kWh peak, 5p/kWh off-peak and about 10kWh per day. Hence around £2 per day saving. You are of course right that electric heating will bring the payback in, but you wont get a huge amount of heating out of an old Leaf, the capacity isn't big enough. Today we've used 8.7kWh of electricity so far, and 115kWh of gas; even with a 300% efficient heat pump that would require about 50kWh's worth of battery, so two and a bit early Leafs.
Problem is, we're paying 4p/kWh for gas at the moment, so with electricity at 5p/kWh overnight and 300% efficient heat pumps, you're only saving 2.3p/kWh which at our usage is about another £3 per day in the depths of winder, and almost nothing in the summer so say £1.50 a day on average. OK £3.50 per day is more than £2 but it'll still take a while to pay for two Leafs and all the stuff needed to hook them up! And that's assuming you already have the heat pumps installed; they're bloody expensive!
The consumer gas price rises which are coming this year are going to hurt, but I think they're necessary (and indeed insufficient) in order to make anything else remotely viable for home heating.
Edited by kambites on Tuesday 25th January 22:17
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