Flywheel generators for car chargers

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Catweazle
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Flywheel generators for car chargers

Post by Catweazle »

With electric car use going up, and battery tech allowing faster charging, does the board expect to see "flywheel" type energy stores in petrol stations that don't have a huge electricity connection ?

Or will capacitor / battery banks be better ?
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adam2
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Re: Flywheel generators for car chargers

Post by adam2 »

Unlikely IMHO. A flywheel to store enough energy is a relatively costly item and a large grid connection might be cheaper, and will certainly be more efficient.

And remember that a flywheel does NOT reduce the average energy demand. If a filing station is to charge 100 vehicles an hour, each one of which needs an average of 25KWH to "fill" it , then a a grid connection of about 2.5 MW will be needed.

A flywheel might in theory be applicable to a small rural charging place with a limited grid supply, and that only charges a couple of vehicles a day. But in practice I suspect that a static battery would be more viable.
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PS_RalphW
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Re: Flywheel generators for car chargers

Post by PS_RalphW »

The new charging stations at Braintree and Rugby havev12+ chargers each rated at 350KW. That is 4MW peak demand. All from the grid.
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BritDownUnder
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Re: Flywheel generators for car chargers

Post by BritDownUnder »

It's an interesting issue. I would think charges that are well used and are close to grid connections that are 'strong' will not have problems. I have heard that chargers may cause harmonic issues on the grid. I don't think flywheels are practical or cost effective - too many mechanical and moving parts and probably more expensive that batteries are now.

This has been discussed in Australia as there may be a requirement for large truck charging stations on remote roads that may not have a grid connection. In this case a solar PV powered charging station may be of some use with perhaps a battery or capacitor added to the charging station. Solar also has some advantage of being DC. These will all add costs and maybe there could be a tariff system introduced that makes charging during sunshine hours cheaper than charging from the station battery. Time will tell.
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Catweazle
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Re: Flywheel generators for car chargers

Post by Catweazle »

I saw a photo of a remote car charging point with a large diesel generator feeding it. I thought of "flywheel" because it's possible that new battery tech could take a very high charge rate, and remote stations might need just a couple of these charges a day.
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Re: Flywheel generators for car chargers

Post by kenneal - lagger »

Catweazle wrote: Mon May 10, 2021 10:05 am I saw a photo of a remote car charging point with a large diesel generator feeding it.
That would be our situation in effect so until cheap, fast, local charging is available we will be using petrol and diesel engines in this household I'm afraid.
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adam2
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Re: Flywheel generators for car chargers

Post by adam2 »

kenneal - lagger wrote: Mon May 10, 2021 3:44 pm
Catweazle wrote: Mon May 10, 2021 10:05 am I saw a photo of a remote car charging point with a large diesel generator feeding it.
That would be our situation in effect so until cheap, fast, local charging is available we will be using petrol and diesel engines in this household I'm afraid.
Under present circumstances I agree that petrol or diesel fueled vehicles make more sense in your situation.

Looking a few years ahead, cheap second hand electric vehicles with reduced battery capacity may become available.
If such vehicles became cheap enough, then purchase of TWO similar cars might be affordable, use one and leave the other at home connected to your off grid system.
Arrange such that when your house battery is full, that the surplus is diverted into the EV battery. If no such surplus is available, then adding a few extra Kw of PV is affordable.
PV modules are now down to 50 pence a watt, so another 4 Kw is only about £2,000. That would charge a modest capacity EV in a day in the summer or in several days in the winter.
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Catweazle
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Re: Flywheel generators for car chargers

Post by Catweazle »

There's a business opportunity for someone to put a load of batteries or a generator on a truck and give people emergency charges, AA style.
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BritDownUnder
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Re: Flywheel generators for car chargers

Post by BritDownUnder »

Catweazle wrote: Mon May 10, 2021 7:46 pm There's a business opportunity for someone to put a load of batteries or a generator on a truck and give people emergency charges, AA style.
I agree!

There are also informal business opportunities for people to give people a quick charge using a normal 13Amp outlet from their own home to a person in need and with cash. I know the output is not great but could be used in an emergency. I would guesstimate that you could add 10 miles of car range per hour which may be enough to get you to the next supercharger in an emergency. I could also see some farms in the Scottish highlands getting fed up with such requests over time.

I don't know why Ken does not get more solar for his farm other than for cost reasons. Perhaps you could also get an electric tractor.

I think most practical form of energy storage for car chargers in a low grid capacity area is to use a large battery. I have heard that there will be a flood of 'worn out' former car batteries emerging in the near future that will not store 80% of their initial 'nameplate' charge which will affect the range of a vehicle but will be quite acceptable as part of a stationary battery to provide high speed charging.
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PS_RalphW
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Re: Flywheel generators for car chargers

Post by PS_RalphW »

The AA already has mobile electric car charging vans in its fleet. I have watched utube videos of people cadging charges from 13 amp plugs when they run their batteries flat. However the financial returns would be so low as to make it a very poor business model. Used Nissan leaf battery packs are already in demand for solar pv back up modules. I could have got 80% of the trade in value of my old leaf for the battery pack alone. The new Ionic 5 has a 13amp output socket which can charge another car from its own battery.
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