Electric car climate control

[ppppenguin]

Car battery packs are now often reckoned to last the life of the car. In very rough terms 250 miles per charge and 1000 charges give you 250,000 miles. Old car battery packs are re-purposed as domestic batteries, to work with PV. The reduced capacity is less important and the operating conditions are kinder, with less temperature fluctuation and lower charge/discharge currents.

The currents in an electric car traction system are quite scary. If the battery is 400V and you have a peak 200kW output that's 500A. OK, 200kW is about 270hp, a fairly powerful car, but it's not outlandish. You really don't want to get yourself or anything metallic across the battery.

[Mark Hennessy]

I started reading a discussion about battery life on the EEVBlog forum the other day - largely about the batteries in the Nissan Leaf, which apparently aren't cooled properly. That led to a YouTube video that discusses battery chemistry at length. I've only watched the first half-hour or so, but found it interesting and hope to return to it later. Some interesting thoughts in there about how batteries are developed and tested - right now, things are moving so fast that the standard accelerated life testing is too slow - an alternative approach is described. Sorry to be hazy on the details, but as I say, I've only seen part of it. And I was doing something else at the time, so not really listening properly. But I'll re-watch the first part when I do get back to it. What I have seen makes me wish I'd paid more attention during chemistry at school!

https://www.youtube.com/watch?v=pxP0Cu00sZs

The original conversation started with the idea of using the Nissan Leaf to power your home and the grid - a bit like a Tesla Powerwall...

https://thedriven.io/2020/07/09/nissan-l...this-year/

Interesting times!

[ppppenguin]

There's an whole alphabet soup of V2x technologies: https://en.wikipedia.org/wiki/Vehicle-to-grid
The simplest is V1G, that's simply charging your car when there's spare power on the grid, right up to full V2G where lots of EVs form distributed grid scale storage. V2H is an intermediate step, like using a battery bank with your solar PV to help power your home.

One thing that solar PV won't do, is run your home during a power failure. I don't think anyone is yet making kit for domestic PV that will do a reliable changeover into "island" mode. You don't want your PV and/or batteries to try and feed the whole street when the power fails. They won't do it and it's a hazard for the linesmen.

[peter scott]

can the 1920 street wiring cope with the numerous charging point needed. When our street was built,  most houses had just lighting and a couple of sockets, no washing machine, tumble driers or immersion heaters those days , so the under ground cable is really slender. Ted

One of the arguments put about by "Musk"ovites is that no hydrogen network exists but the electricity grid is already there! "Fake news!"

Peter

[Cobaltblue]

Although I am pleased that Elon Musk has managed to make big steps forward in Electric car technology I tend to find his pronouncements unhelpful.

My big concern with Hydrogen at the moment is the way its made.

We all know you can crack water into Hydrogen and Oxygen with nice off peak electricity.

In the main Hydrogen is made with what's known as SMR a quote from one of the many sources on the internet.

Steam methane reforming, or SMR, is the most common method for producing hydrogen at large industrial scales. SMR causes the methane found in natural gas to react with steam, producing hydrogen and carbon monoxide. The carbon monoxide undergoes further reactions, generating more hydrogen and, crucially, carbon dioxide—a heat-trapping gas. Despite this, fuel cell vehicles driven on SMR-sourced hydrogen are still cleaner than their conventional counterparts, and produce even fewer emissions when the methane comes from waste, not natural gas.

I am sure we all know that Electricity isn't always made cleanly either I always find it disingenuous car manufactures claiming how clean these technologies are.

I am not directly involved but there were discussions about building combined EV charger/Hydrogen for garage forecourts where the hydrogen was produced in situ rather than transported. I can only guess at the thinking and technology behind this.

I was talking to one of my colleagues yesterday he has a 3 1/2 year old Hyundai IONIQ that he bought second hand just after Xmas this year.

He has a tariff that gives him electricity at 6p per KWH between 3:30 and 6:00 AM which is when he charges his car.

He is getting over 5 Miles/KWH on his 30 mile daily commute so 36p per day that's not the total end to end cost though because obviously you will put more power in than you get out but even allowing for that it will be under 40p per day.

It costs him so little he mostly doesn't even bother to take advantage of the free charging in the office

Unlike me 

Cheers

Mike T

[Murphyv310]

When I looked at the Renault Zoe I was shocked that the cheapest battery lease was around £45 pm, more than my petrol use in a month.
At that rate it wasn't financially sensible for me. Whether that has changed I don't know.

[Murphyv310]

One other thing that went through my mind is grid capacity.
I'm sure this has been discussed before but I think the goal posts may have moved.
I know that Hunterston power station in North Ayrshire will close I belive next year due to cracks in the granite reactor. Is not the big Chinese power station in southern England not on hold? Other old power stations are in line for decommissioning too, wind isn't always reliable and with a no deal brexit looming, that could even mean issues with power sharing with the EU. If the demand rises with thousands charging 18650 cells this could lead to blackouts.

[ppppenguin]

Yes, grid capacity is a problem, but not unsolvable. Electric cars will also be part of the solution with V2G: https://en.wikipedia.org/wiki/Vehicle-to-grid

What is certain is that in the UK we are generating almost nothing from coal, less from gas and a lot more from wind than we were a few years ago. The trend looks unstoppable as grid scale storage becomes more available. This means that the supposed unreliabilty of wind will be much reduced. Ultimately you keep some gas fired plant as a backup, plant that's cheap to build though expensive to run.

I rather doubt that Hinkley C will ever be completed: https://en.wikipedia.org/wiki/Hinkley_Po...er_station

I am well aware that the fairly recent large scale power failure was partly caused by failure of a wind array. It was also due to the simultaneous failure of a gas fired power station. There wasn't enough spinning reserve to cover the loss of 2 major power stations at the same time. That's not a reflection on the relibaility or otherwise of wind, it's a matter of grid management and how much cost should be devoted to rare double failures. There was also the ridiculous business of some electric trains not being able to restart without specialist attention, even when the power returned. The term "spinning reserve" is starting to look old fashioned as more large scale batteries come online.

[Murphyv310]

Can you imagine driving to work, plugging your EV in and there is a major issue with the grid and your EV is then powering the grid. You then jump in the car and see you have insufficient range to get home. I somehow think that won't please you after a hard day's graft.

[Nick]

...due to cracks in the granite reactor...

That made me chuckle - it is in Scotland after all...