How Many Solar Panels Do You Need To Charge An Electric Car?

dude charging his car with solar

If you are thinking of buying an electric car and have solar then you need to read this.

I recently wrote about how an electric car revolution is coming thanks to declining battery costs and rising environmental concern.  I made a promise in that article I would soon write about charging electric cars with rooftop solar and soon is now.  Or at least it soon will be.

One concern that came up in the comments was whether people could fit enough panels on their roof to charge an electric car.  But the good news is a car that’s driven the average distance for an Australian passenger vehicle is likely to require less than 8 kilowatt-hours a day.  This means for most households 2 kilowatts of solar panels will produce more electrical energy over the course of a year than an electric car will consume.  Most homes can fit 2 kilowatts of panels on their roof in addition to enough panels to equal or exceed household electricity consumption.

The bad news is 56% of Australian families have 2 or more cars.

Electric Car Kilowatt-Hour Consumption

The number of kilometers an electric car can drive per kilowatt-hour of stored electricity varies.  Fortunately, it is easy enough to use US Environmental Protection Agency figures to determine range per kilowatt-hour of battery storage1.  Some examples are:

  • Tesla Model 3:  7 kilometers
  • Chevolet Bolt:  6.4 kilometers
  • Mitsubishi i-MiEV:  6.3 kilometers
  • 2016 Nissan Leaf:  5.7 kilometers
  • Tesla S sports car:  5.3 kilometers

Because electric cars won’t allow their battery to go completely flat to protect it from deterioration, the real kilometers per kilowatt-hour are slightly higher, but it should make little difference, as modern electric cars don’t leave much juice in the electric juice pack once they hit zero kilometers of remaining range.

Unlike the range figures that come from Europe or Japan, the US ones are reasonably realistic and it is possible for a normal driver to replicate them or even do better if they’re careful.  But if your driving style consists of alternating between stomping on the accelerator and stomping on the brake then I’m afraid you’ll do much worse, while if you someone who drives like you are gently making love, then you’ll probably be arrested and I strongly recommend getting the tinted windows option.

70s Smooth Style

It is possible to now buy electric cars that look even better than they did in the 70s. (It’s impossible to find pants that good though.)

Charging Losses

The figures above are for energy that’s already in a car battery pack.  Unfortunately, some energy is always lost squeezing it in there in the first place.  Losses occur from changing household AC power into the DC power car battery packs need to charge2 and energy is lost by the batteries themselves as they charge.

This study from 2014 found charging a Nissan Leaf was only 84% efficient when slowly charging from a from a standard US power point3 and 89% when a home charger that provides more power was used.

As most people are likely to use a home charger rather than just plug into a power point, 90% efficiency seems like a good rule of thumb for charging, especially since modest improvements in efficiency are likely.  Mind you, it will vary depending on the car and situation.  I have read some truly atrocious estimates for the Tesla S sports car.  Hopefully their new Model 3 will do better, as it is designed for people who are not entirely made of money.

If you buy a car that gets 7 kilometers per kilowatt-hour of battery pack charge and take care to drive reasonably efficiently, then you are likely to get 6.3 kilometers per kilowatt-hour of electricity you charge it with.  If you are a bit of a sloppy driver, and I think most of us are, you may only get 5 kilometers per kilowatt-hour.

Average Kilometers Driven

The average Australia passenger car is driven around 14,000 kilometers a year, which comes to an average of about 38 kilometers a day.  So if you get 5 kilometers of range for every kilowatt-hour of charge you attempt to stuff into your car, you will use almost 8 kilowatt-hours a day.

Of course, you are likely to already know roughly how many kilometers you drive a year, so of course you should base your estimates on that rather than the average.

The Amount You Drive May Increase

Once you go electric it’s possible you will end up driving more kilometers than you used to.  This is a claim I’ve seen more than once on the internet.  The two main reasons given are:

  • The lower cost of driving encourages people to drive more.
  • Electric cars are so pleasurable to drive you won’t want to stop.

I find it hard to believe the first explanation will have much effect on Australians.  Sure, an electric car could save over $4 an hour when driving around town, but most of us value our time at a far higher rate than that and so the savings in running costs are not likely to encourage us to spend much extra time behind the wheel.

The second explanation seems more likely to me, as there are definitely people out there who take a great deal of pleasure in the high performance and smooth ride electric cars offer.  Personally, I think any form of transport that doesn’t make your teeth rattle and come with a chance of kidney failure is kind of boring, but I think riding a horse is a sensible thing to do, so I’m just weird.

Solar Panel Capacity Required

If you decide you are likely to drive your electric car the Australian average of 38 kilometers a day and estimate you are likely to get 5 kilometers per kilowatt-hour of electricity you use shoving energy into its battery pack, then you will need to charge it with an average of 7.6 kilowatt-hours a day.  Most Australian households can expect to get around 4 kilowatt-hours of electricity per day for each kilowatt of north facing solar panels they have and around 3.4 for east or west-facing panels. So it would take 1.9 kilowatts of north facing solar panels to match the electricity consumption of the car.

1.8 kilowatts of panels

1.8 kilowatt of solar panels using high efficiency SunPower X22 panels. Their total area is 8.1 square meters.

Things are a little worse in Melbourne, which is well known for being the least sunny mainland capital, and there one kilowatt of north facing solar panels will only produce an average of around 3.5 kilowatt-hours per day and around 3 if they face east or west.  Hobart is about 8% worse than Melbourne.  (Mind you, there is nowhere in Tasmania you can drive that is more than 470 kilometers from Hobart.)

1.89 kilowatts of 270 watt panels

1.89 kilowatts of extremely common 270 watt panels. Their total area is 11.6 square meters.

So in general, 2 kilowatts of solar panels should be enough to provide power equal to or greater than the consumption of the average electric car.

Number Of Cars Per Household

Using figures from the 2016 census it is possible to estimate the number of cars Australian households have:

  • 8% of households have no car.
  • 36% have 1 car.
  • 37% have 2 cars.
  • 19% have 3 or more cars.

The more cars a household has the fewer kilometers each is likely to average per year, but despite this it may be difficult for households with multiple cars to install enough rooftop solar to charge them all and meet household electricity consumption.

It is likely that most multiple car families will just buy one electric car at first, but I have heard of families getting one electric car and then rapidly changing all their vehicles to electric so they don’t have to fight over who gets to drive the electric car4.

Many Cars Are Parked At Home During The Day

Some people seem to be under the impression almost all cars are driven to work during the day and so aren’t available for charging by home solar, but a large portion of privately owned cars are parked at home for the majority of the day.

This is because many car owners are retired, don’t work, unfortunately can’t find work, shift workers, people who work from home, or those who walk, cycle, use public transport to get to work without needing to park their car at the train station, or simply own more cars than they can drive at one time.

Of course, if you are one of the many people who will be driving their electric car to work, the fact that many other cars are parked at home during the day isn’t of much use to you.  But there are good economic and environmental reasons why it may not matter if you send your solar electricity into the grid during the day and charge your car using the grid overnight.

You May Save More By Charging Overnight

In Victoria and NSW it is possible for the solar feed-in tariff to be higher than the cost of charging with a controlled load tariff overnight.  In these cases charging your car with solar electricity will cost you money.  In Victoria these kind of retail electricity plans are very common.  In Sydney they are harder to find, but one example is Origin’s Solar Boost plan5 that pays a feed-in tariff of 15 cents while charging 13.5 cents per kilowatt-hour for a controlled load with no daily supply charge.

Although solar households are normally better off with a standard tariff, in these two states it is also possible to have a time-of-use tariff with an off-peak rate that is lower than the feed-in tariff.

It is extremely unlikely that money can be saved this way in other states, but using a controlled tariff can be a lower cost option for those who are either unable to charge their car during the day or for those who don’t have sufficient surplus solar energy to charge their cars.

Controlled Load Tariffs Operate For Limited Times

While controlled load tariffs are lower than standard rates, sometimes much lower, they have the disadvantage of only being available for a limited period of time.  Most are for 8 hours overnight, but in Queensland they sometimes turn theirs on during the day thanks to high rooftop solar output.

If your car needs to be charged when the controlled load tariff is not available, it could be plugged into a normal power point for a slow charge or a second charger that is not on a controlled tariff could be used — but paying for a second charger that is rarely used is an expensive option.  Driving to a public charger is also an option.

There May Be Special Rates For Electric Car Charging

In the future there may be a wide range of special plans available for charging electric vehicles.  They are likely to become common as Australia’s renewable energy capacity increases, resulting in periods of surplus renewable generation.  They may offer a very low cost method of charging electric cars.  There is already a special offer by AGL that allows electric cars to be charged for $1 a day.

AGL’s $1 A Day Charging

AGL’s electric car plan allows an electric car to use a home charger at any time for only $1 a day.  While this sounds like a good deal, it can still be much cheaper to use a controlled load in Victoria and may also be cheaper in NSW, depending on the vehicle’s average energy consumption.  And even in locations where it is cheaper there are some aspects that aren’t all sweetness and light:

  • You will need to pay for the installation of a separate meter.
  • You can only charge a single car with the plan — which makes me wonder what you can do if a guest rocks up in an electric car.
  • You can’t use it as part of running a business.
  • $1 a day is only fixed for 12 months, after which they can raise it if they wish.
I'll buy that for a dollar!

Call me a suspicious old fart, but the location of that lettering makes me wonder if that’s really an electric car at all.

Exported Solar Power Still Provides Environmental Benefit

If a household installs enough extra rooftop solar capacity to charge their electric vehicle but instead sends it into the grid, it will give the same environmental benefit as if it had been used to charge their car.

This is because if a solar system sends 8 kilowatt-hours of electricity into the grid it will reduce fossil fuel generation by around 8 kilowatt-hours and if their electric vehicle then uses 8 kilowatt-hours charging from the grid at night it will increase fossil fuel generation by around 8 kilowatt-hours.  So it evens itself out overall.

So long as a household produces surplus solar electricity equal to the consumption of their electric car, it shouldn’t make an environmental difference if the car is charged from the grid or from rooftop solar.  It is even possible sending solar electricity into the grid during the day and charging at night will result in more environmental benefit by causing greater harm to the economics of coal power, resulting in coal power stations closing down sooner than they would have.

Charging With Solar

The simplest way to charge a car using rooftop solar is to plug it in during the day when the sun is shining.  Provided the amount of surplus solar electricity being generated is equal to or greater than the amount charging the car, only solar power will be used.  However, if the amount of solar power is less then at least some grid power will be used.

How likely a vehicle is to draw on grid power will depend on how much power is used to charge it.

Level 1, 2, and 3 Charging

Level 1 charging is the slowest rate that’s normally possible and uses a normal power point.  A car may be limited to the slow Japanese/US rate of 1.4 kilowatts or it may be able to charge at the European rate of around 2.3 kilowatts.

Level 2 charging involves using a hardwired charger installed in your garage or potentially outside.  These vary considerably in price and in how rapidly they can charge, with a power output of 3 to 7 kilowatts being typical.

It is possible for the terms of your car’s written warranty to require a level 2 charger be installed where the car is kept and this can be a considerable expense, especially if you need to move.

Level 3 charging is rapid charging using dedicated public chargers.  Some electric cars are not capable of effectively using these and the larger the car’s battery the more power they can be charged with at once. These types of chargers are most likely to be used by people traveling long distances and those caught short of charge for some reason. The large majority of charging will be done at home, with some people charging at work if facilities are available.

Slow Charging Can Suit Solar

The more slowly a car is charged the easier it can be to charge it with solar power.  If your rooftop solar is producing 3 kilowatts of power, your home is using half a kilowatt, and you start level 1 charging your car at 2.3 kilowatts, then all the power provided to your car will be solar.  But if you started level 2 charging your car at 3 kilowatts a portion of the power would come from the grid and if you started charging at 7 kilowatts more than half would be grid power.

If it is not possible to keep grid electricity use to a minimum then it can be cheaper to use a controlled load tariff and not use a combination of grid and solar power.  One way to attempt to maximize solar power charging is to use a timer so the car will only charge when solar output is likely to be high.  Another method is to use a relay that will only turn on the charger when sufficient surplus solar electricity is available.

I wrote about using a Fronius relay here and a SunMate solar diverter can also do the same.  (But note that only the SunMate’s threshold power function can supply electricity to charge an electric car.  Solar diverter output meant for heating elements definitely cannot be used.)

Charging On The Weekend

People who drive their cars to work may want to know if it will be possible to charge them on the weekend using solar power.  It could be done, but the battery pack would need to be large enough to last the week and, for anyone who does close to the average amount of driving, their solar system would have to be very large to charge their car over two days.  If the weekend was overcast or the car needed to be used during the day it would cause difficulties.

Using Home Batteries To Charge Car Batteries

While it is possible to charge a home battery system during the day with solar power and then charge an electric car in the evening with the stored power, this is very unlikely to be cost effective compared to using a controlled load tariff.

For example, if you already have a home battery and you optimistically estimate a replacement will cost 15 cents for each kilowatt-hour it stores and your feed-in tariff is 10 cents, then with losses it would cost around 26 cents per kilowatt-hour to charge your car this way, which is higher than a controlled load tariff.

The place where this will come closest to paying for itself is Perth where the feed-in tariff is a low 7.1 cents and controlled load tariffs are no longer available6.

How Much Solar To Install

The exact amount of solar energy required to offset the consumption of an electric car will depend on its make, distance driven, and the driving habits of those using it.  But, in general, one that is driven the average amount for an Australian passenger vehicle will require just under 2 kilowatts of solar panel capacity to offset its consumption.

But this doesn’t change the conclusion I arrived at previously that households should install as much solar as they reasonably can.  The likely need to power electric cars in the future just makes this more important.  And if in the future we are all using robot electric taxis instead of owning our own cars, many people may still wish to install enough solar to offset the energy consumption from their robo-taxi use.

Footnotes

  1. I was told the US EPA hasn’t tested the range of the new Tesla Model 3, but they have information about it on their website, so I will assume for now they actually have tested it and didn’t just take Elon’s word on what its range is.
  2. Specially designed inverters that are also electric car chargers, such as this HD Wave one by SolarEdge, may reduce but can’t eliminate these losses.
  3. This only allows a Nissan Leaf to charge at the slow rate of 1.4 kilowatts.
  4. Kind of like how my first wife and I used to argue over who would ride the horse that liked to eat meat.
  5. Not Origin’s Solar Boost Plus plan that requires you buy rooftop solar from them and only applies for one year.
  6. But at the moment we are hearing that West Australians are finding it very difficult if not impossible to get permission to install grid connected battery systems
About Ronald Brakels

Many years ago now, Ronald Brakels was born in Toowoomba. He first rose to international prominence when his township took up a collection to send him to Japan, which was the furthest they could manage with the money they raised. He became passionately interested in environmental matters upon his return to Australia when the local Mayor met him at the airport and explained it was far too dangerous for him to return to Toowoomba on account of climate change and mutant attack goats. Ronald then moved to a property in the Adelaide Hills where he now lives with his horse, Tonto 23.

Comments

  1. I had a ride in the solar taxi which toured the world.
    The car hwas covered in panels and towed a light trailer also covered in panels.
    The PV was by Q-cells and they had panels on the roof of their building.
    Basically if it wasn’t raining and teh car was driven in and parked in the sun, the car could keep going indefinitely. But if it rained they needed to charge from wherever they could and sometimes that was mains, but the mains power used was offset by the solar electricity from the building roof. So on a net basis the car toured the world with no net grid usage (although the solar input from the roof was in one country and the power from the mains was almost all in other countries and not interconnected.

    https://www.earthmagazine.org/article/around-world-solar-taxi

    • Yeah! (“I had a ride in the solar taxi which toured the world.”) Bloody cabbies will do anything they can get away with to pad the fare!

  2. Ted Szyszka says

    No biggie, but annoying just the same … any reason for yankee kilometer in lieu of our kilometre?

    • Ronald Brakels says

      Well, I used to spell it “re” instead of “er” but then an Englishman got mad at me and demanded to know why I was spelling it the French way instead of the English way. He said that unless we used Germanic spelling, as God had intended, then the Normans had won and the martyrs of the rebellion of 1069 died for nothing.

      Either that, or my spell checker is set to US.

    • If it’s American it’ll be a kill-ometer

  3. Ronald,
    we have owned an Imiev for nearly 4 years. My wife drives it about 75Km/day during the week, so because she cannot charge at work, we charge on off-peak overnight.
    In our case, we have 7.5Kw of solar that grid feeds to Enova at 16c/Kwh. In our case it is cost neutral charging off-peak, although it is more likely to be coal-fired power overnight!
    We use about !2Kwh/night for charging. The Imiev draws just over 9A continuous for the approximately 6 hours charging. (It is important to use a 15A power point, really heavy extension leads (if absolutely necessary) & keep the leads straight, because they get quite warm.
    Our car has now traveled 65000Km, & the battery is showing signs of age.

    The running costs of the electric car are extremely low. 15000Km services average $400. We have used 5 tires so far. Other than that, nothing.

    As far as Solar charging design goes, I would suggest the largest system you can fit. It is good to have the required current available for as long as possible to charge an EV. Also good to arrange your panels East & west, rather than North, because this gives a longer power availability.
    In the House we have in Lismore, we have 3Kw on the East, & 10 Kw on the West. This moves the peak generation to later. (At home our 7.5Kw faces North)

    • We have had an Mieve since 2012. We have just passed the 50,000 mile mark. Ye step battery has degraded I would say about 5% or so. We have put the fuel savings in the bank and when it come time to buy a new battery pack (should we keep the car) we will have the money to do so.

      We drive it daily and our RT is typically less than 40 miles. We drive it 99% of the time. The other car we have is a hybrid that gets average 50 mpg.

      No the good news i that if 56% of Australians have two cars then they should all replace ONE o fetch ICE cars with EV. Then that way you have the ICE as a back up for distances that you EV cannot handle. Plus they are less expensive to own and operate.

      The MieV has had Xero costs other than tire replacement at 40,000 miles and one auxiliary battery. YEs an EV seems to be much less expensive to maintain.

  4. Tom Martin says

    It appears that the new Solar edge 7600H-US HD Wave inverter can divert excess solar energy to boost your EV charging power. Thus might work well in my area (HI) where TOU off peak is 9am-5pm and one would like to charge EVs during day. Any comments about this new inverter?

  5. Bruce Hughes says

    https://www.solarquotes.com.au/blog/australia-electric-truck-mb0123/

    http://www.seaauto.com.au/ev-10/

    I see a vision splendid… for an energy re-charge service station.

    Unfortunately, I think I’ll need more than your yard for solar panels to store energy in 16 x 10kWh Redflow batteries so that the truck can be charged in six hours at 22kWh rate.

    Working on 9kWh out of a battery at a rate of 3kW for 3 hours. Two batteries would be 6kW in 6hours.
    Then at 22kWh rate of charger 22/3 equal 8, then 16 to get 6 hours to recharge the 120kWh battery bank. That’s assuming no external electricity , all energy from batteries that have been charged during the day…..
    Are my figures right?

    Regards,
    Bruce Hughes
    Pickles Environmental Conserving Systems
    P.E.C.S

  6. We are aiming at building a zero net carbon and off grid cellar door and winery in the Adelaide Hills. This will be at our Lenswood vineyard. We already have the plans done but are waiting on the AHC for approval. In the meantime I have been researching, talking to people and attending things like SHD. Unfortunately I missed the recent meeting on a renewable energy future in SA which I heard that you gave a speech at. Tesla have offered us two destination chargers and we are looking at getting a “normal” EV charging station as well. I have been talking with Russell Sheppard who seems to know a bit about chargers and solar pv. However, I am thankful for your post as I have been finding it quite difficult to get a straight answer on how much PV I will need for these 3 chargers. Can you help? Unlike a house / home we will be open during the day and hardly ever at night. Our opening hours will be 10 or 11 to 5pm. I imagine EV owners will most likely use the opportunity to charge or top up their cars whilst having lunch or coming for a tasting, so we’ll be looking at relatively short periods of charging eg an hour or two, and if over lunch most likely between 12 and 3. We will be open 3 days a week, initially, then 5 days, when demand allows. How many KW of PV panels will we need to run these three chargers?

    • Ronald Brakels says

      Hello James.

      Ronald here. It wasn’t me giving a speech. Maybe it was Finn.

      I appears that a Tesla destination charger can provide 9.6 kilowatts in Australia. Unfortunately, I can’t be certain of this, as Tesla doesn’t appear to provide this information on their Australian site.

      A typical universal charger provides 7 kilowatts.

      If you had two Tesla vehicles and one other electric vehicle charging they could draw 26.2 kilowatts. As solar panels will produce around 80% of their rated output around lunchtime on a clear day, About 33 kilowatts of solar panels would be required, which is a very large system.

      If you instead think you’ll only average one electric car charging at a time, then for a Tesla you’d require 12 kilowatts of panels.

      If you are happy with just generating enough solar electricity to equal the kilowatt-hours used for charging, then you’ll need to estimate how many kilowatt-hours that will come to. If you think you will average 2 hours a day of electric car charging a day of mostly Teslas, then that would come to 19.2 kilowatt-hours a day and 5 kilowatts of solar panels would be enough to produce that much on average in SA.

      • Thanks for the advice. I just want to make sure that I have enough panels to charge a car or I will look like I haven’t thought the whole thing through! Also, on a different subject, what is your opinion of perovskite cells? Are we likely to see panels of these in the near future and if we are what price do you think they will be (how long is a piece of string, I know) plus will they be 30% efficient or what?

        • Ronald Brakels says

          Hopefully, perovskite cells will be able to provide significant cost reductions for PV, but beating plain silicon will be tough and there are a number of issues still to be overcome. A major one, lifespan, may not be a deal breaker as commercial users often want their investments to pay for themselves in 7 to 8 years and may not care too much if the panels degrade or need to be replaced after that.

  7. Here is the future of transportation:

    EV + PV (i.e. renewable energy) = Free fuel for life.

    The displacement of fossil fuel by electricity is generally worth more than the displacement of grid electricity because driving with electrons i s so much more efficient than driving with inefficient fossil fuel engines that are about 25% efficient when an electric motor and drive train is over 85% efficient

    JD

    P.S. yes you have to spend money to harvest the electrons, but once paid for the electricity is free. It is delivered to your home free of charge too! No one sends you a bill for delivering sunshine to your PV array. Correct?

    • Correct?….Maybe…..So far.
      I’ll give you odds that as soon as alternative energy (or anything!) looks like a working proposition it’ll be taxed. I can remember when petrol cost tuppence a gallon…..and on a cost per energy-unit you’d find that even solar energy wouldn’t offer any advantage.

      • People might think you are a little bit loony tunes for suggesting that the sun can be taxed. But you may not be too far off the truth. People thought the same about rain water till they discovered that Primary Industries SA (PIRSA) were going to licence the useage of water collected on people’s properties whether in a dam (surface run off from rain water) or bores (rainwater soaking through the soils and rocks). This is done via a meter on the irrigation / bore pump, which is monitored annually by the owner but is open for inspection / verification by the department. So even f you use all the PV power on your own property there is still a way for the government to tax you on it!

        • Certainly: loony enough to have been working out (largely successfully) ways to defeat ‘the system’ for about two or three times as long you’ve been alive. (in accordance with a sound philosophical principle that turns most of our sacred cows into dogfood).

          eg…. you probably wouldn’t remember when receiving (sunlight-like) TV signals was taxed…. and innumerable government agents in vans tarted up as florists or dog-catchers trucks loaded up with detection equipment cruised entire cities seeking out the movement of relevant radio-waves and pinpointing the houses that had had a TV stashed under the bed until after dark and the aerial hidden in the ceiling…..to avoid a fee (5 pounds per year from memory). This was back in the days when radar systems were still built from string and a protractor….. and ‘line-of-sight’ just before the shit hit the fan.
          These days, technology being what it is, you have a job hiding a fart in a sewerage-farm from ‘Them’!

          That’s not to say one should surrender. But I am glad that I’m much nearer the grave than the cradle.
          They WILL catch up in due course (and I could tell you why!), and one day I expect all the ‘authorities’ (including my politician-voting fucking-‘righteous’ PC neighbours!) to come trooping up my driveway waving their torches and pitch-forks, along with claims, warrants, court-orders, etc etc , with their guns drawn and handcuffs rattling.
          Current ambition is that ~ just as they lob on the doorstep ~ I have my heart-attack!….and sail off into eternity with a smile fixed forever on my face in the knowledge that I never quit……let alone co-operated.

        • Just figured out what you meant. Here —-> y’go.

  8. If you could respond to my above comment and here also I can then get the follow up comments. I forgot to hit the relevant button on the last comment!

  9. —-> “The bad news is 56% of Australian families have 2 or more cars.”

    The even WORSE news that the sun don’t shine just when you want it to. Depending the weather, suicidal birds, rats, etc, you may not get your required 7.5kwh until next week.
    ………and if you’re taking your wife ~ or, worse, girlfriend, to hospital because she’s gone into labour and you run out of fuel because the car’s been recharging for only 34 minutes, good luck with getting the RACV to come out with a jerry-can full of volts. (or amps, if that’s your favourite brand.) Neither will you be able to ‘crash-start’ them in an emergency.
    Anyway, most people would miss their daily dose of CO.
    I’m the greatest non-waster/innovator you’d ever meat, but electric cars were tried nearly 200 years ago and failed badly. The only real difference these days is that the electricity cheaper…….Right??
    …………yeah. right!

  10. A good few years ago Melbourne Uni. ran some experiments on hybrid vehicles –> Hydrogen/petrol.
    Dunno what happened, but they had an old Ford Falcon running around Melbourne for quite some time.

    I later got to know a couple of young whiz-kids who worked out (very successfully and above all SIMPLY) ) a way to extract the hydrogen onboard, from water, by using big batteries in the boot that were recharged in several ways, including kinetic energy from the car’s momentum. (and an ordinary-looking ‘Black Box’.
    Apparently the ultra-efficiency more than made up for the usual intrinsic losses.

    From memory (fading) they could fit a system to most vehicles (with plenty of space under the bonnet: ie an OLD chipless vehicle) in a week for about $4k.
    (I saw an old International 30-cwt truck they bought and converted in situ and drove down to Melbourne from Mildura all in under a fortnight.) And their test-bed covered over 1 million km in (memory?) about 4 years.
    Dirt cheap to run and virtually pollution-free.

    I know about the no-such-thing-as-a-free-lunch mathematics, and am more cynical than most; but if I’d had the money I’d have put it on the table without hesitation.

    Despite a lot of effort they couldn’t get it past the shitloads of officials and officialdom ~ hence no funding ~ and quietly disappeared.

    Point is, there ARE always options to look at out there.
    ……..perhaps, one day, even a politician-free world. (or would that come under the pollution-free rules?)

    • Mikhailovitch says

      Simply nonsense, I’m afraid. Efficiency does not make up for losses, it just reduces the effect slightly. Carting huge batteries, a conventional engine tuned to hydrogen, and a bunch of water is a substantial burden, and there are significant losses at all stages of the process. Simply, physics says it doesn’t work. Once your batteries run down ( yes, what you’re actually running on is batteries charged from the mains), you’d find your actual range was very short indeed. You’d do much better to have your batteries running electric motors to drive the car. All the other systems just waste energy.

      • WOW! So you actually saw this system NOT working?………
        I do love ‘experts’ who prattle on about things of which they know nothing . They make everybody else look so intelligent…..and if we took them seriously we’d still be swinging around in the tree-tops by our tails.
        Apart from all your other non-substantiated assertions, assumptions and point-missings, I simply make the point that “significant losses” and inefficiencies in the mechanical processes are quite IRRELEVANT if you’re paying NOTHING for the inputs.
        hydrogen-powered vehicles
        ….ps:- and if you’re literate enough I suggest you google up ‘hydrogen-powered vehicles’ for a few million references to this system you insist doesn’t work. Hyundai and Toyoto will be most upset that they’ve wasted so much time and money trying to prove you wrong.

  11. pps… a sentence appears to have miscarried. I suggested you google up ‘hydrogen-powered vehicles’ for a million or two reference which pop up in 0.14 of a second.

  12. It’s now 2018, and the retail market is still not geared up yet to enable charging the DC battery in an EV from the DC power supply from PV.

    It’s still much easier to convert DC to AC in the inverter, and then use one or more AC chargers to rectify the current back to DC for the battery, with the stupid losses at both stages.

    I want to charge a 400V battery directly from the 420V supply from my PV, but have not found a way yet.

  13. Michael Nardella says

    The system size calculation is well and good for when the sun is shining but what about winter? Melbourne has those.

    • Ronald Brakels says

      If your goal is to minimize the amount of grid electricity used to charge your electric car then I’d recommend installing as large a solar system as you reasonably can and using a smart charger that detects when your home is exporting solar electricity and uses that surplus power to charge your car. Of course this will only work if your car is parked at home during the day at least some of the time.

  14. Sunlight may be free now but the ‘Window Tax’ in England ran for 155 years – they always get you in the end.

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