Building an Electric Car Part 2

After about 1 year of part time work my electric car is now on the road and in daily use. There were many challenges along the way, like learning to weld, learning about cars, the various regulations, climbing the Electric Vehicle (EV) learning curve, and several electric shocks!

I have just passed the final government inspection so my EV is now registered and legal. I think my EV is the 5th or 6th registered EV in the State of South Australia.

Amazingly, it actually works! I drive along and use no petrol. Charging from my home PV array I emit no pollution. One very cool thing: I have recycled a 15 year old car, rather than chewing up a large amount of “embodied energy” and precious resources (plastic, steel, labor) that is used to build every new car.

I have a lot to say about Electric Vehicles so will publish a series of posts over the next few months.

Driving an EV

It’s fun and easy to drive. You start off in 2nd gear, and as you slowly depress the pedal the controller starts to gently whine. Then you are off – it accelerates well up to 60 km/hr, better that the original 1.3 litre petrol engine. At about 40 km/hr you change into 3rd gear and the acceleration increases. When you brake you hear a purring sound from the vacuum pump. You rarely have to change down a gear as the car will pull 3rd gear from a standing start. You don’t use the clutch to start, as the engine stops when you do.

When going up a hill you change up a gear in an EV to get more power! This lowers the revs, allows more current to flow and builds the torque. It’s the opposite to a petrol engine that develops it’s power at high revs.

The car is quiet while waiting at traffic lights. You hear birds (!) and all the other engines wastefully idling around you. The car is not silent to drive, you hear transmission and road noise, but not much from the engine, especially at high speed. It sounds very quiet to people on the street.

When you come home just plug in and walk away, like charging a mobile phone. You use 4 cents of electricity for every km traveled. Maintenance costs are near zero as there are very few moving parts (just brakes and tires).

We Need More EVs

To convert a car to electric drive and install home solar panels costs less than a medium size new car. The solar panels would make enough electricity for 60 km travel every day. For free. Such a car would cover 90% of the km traveled by most people every day and last nearly forever. Why aren’t we all doing this?

EV Resources

I listed several EV Resources in Part 1.

Here is my evalbum entry.

Many people have blogged on their EV conversions, here are some EV blogs and web sites that I recommend. Lots of practical ideas and How To knowledge:

13 thoughts on “Building an Electric Car Part 2”

  1. “Charging from my home PV array I emit no pollution.”

    Quite nice. Just curious, did you compare the carbon footprint of the same car for someone using electricity from the grid, which I assume is produced from coal. On one hand, the car is more energy-efficient, on the other hand, you have the loss of the battery, plus the loss of the power plant. For countries that get their energy from coal, I tend to think that hybrids would be more carbon efficient, but I could be wrong.

  2. There have been some studies in this area, I haven’t done the numbers myself.

    The basic thermodynamic efficiency of internal combustion cars is poor – typically 15% of the energy/litre turns into power at the wheels. Electric cars can be 80% efficient. Even my little home built EV gets an equivalent of 120 km/litre at 60 km/hr (based on 38MJ/litre energy of petrol, 5kW cruise power at 60 km/hr).

    Centralised energy production (like a large coal powered power station) is generally more efficient that many smaller motors (like many small hybrids powered by petrol). Not sure how this translates into greenhouse gas foot prints. I suspect oil is cleaner burning than coal, but far more expensive in large stationary applications. Both are non-renewable and dirty, so effectively dead ends.

    A bigger question for me is the embodied energy and use of non renewables in my PV panels. I have heard it said that PV panels collect renewable energy using non-renewable technology. Would love to see a study of this issue, e.g. can we keep making PV or equivalent technology in a fossil fuel depleted world. A simple thought experiment is to put a PV-powered PV factory in the desert and see if if can make more PV panels without significant external inputs apart from sunlight.

  3. Hello!
    I was reading articles about your asterisk work and I found this one.

    This is just awesome. I wish I could do the same.

  4. One thing you haven’t counted in your figures is the efficiency of the battery. I suspect that’s where most of the energy is lost. That being said, if a normal car’s engine is only 15% efficient, the whole coal->electricity->chemical battery->electric motor is probably still more efficient than burning oil directly, especially in a city. The fact that your car is light also helps a lot regardless of its engine (an electric Hummer is still worse than a regular compact car).

    About your PV panels, I think it shouldn’t be counted with the car at all. As long as you’re connected to the grid, 1 kWh you put in the car is 1 extra kWh you need to get from the grid (or one less kWh you can put back to the grid if you’ve really got a lot of PV power). When it comes to the embodied energy in the PV panels, I think it depends a lot on the technology. I think the new low-efficiency amorphous silicon ones aren’t too bad to produce, whereas the high-efficiency ones can be 1) costly and 2) use toxic chemicals like GaAs and others.

    I’ve also been trying to get an idea of how “green” an electric car would be in Quebec where I live. When you first consider it, it looks like zero emissions because about 90% of our electricity is hydro power. However, there’s a lot of others factors to take into account. During our 6-month winter, we need to heat our cars. which we currently do just by cooling the internal combustion engine. With an electric car, you’d need to either waste electrical enery as heat, or have a small fuel tank just for the purpose of heating. During winter, I also think the battery of the car would be less efficient, but I don’t know how much so.

    A second, harder thing to take into account is the fact that Quebec sells its extra electricity to the US, which has mainly thermal (oil/coal, bit of nuclear) plants I think. So 1 kWh I put in the car means an unknown fraction of that kWh gets produced by burning stuff. That’s one reason I’ve always said that heating our houses using electricity (that’s what most people do here) is a bit of a non-sense at the global scale, even if we’ve got hydro power.

  5. Re heating lots of people using electric cars in the cooler parts of North America. The Evalbum site can be searched by location to see some examples. People install electric heaters, for example by placing an electric element in the original heater box. They can use significant amounts of power, for example leading to a 20% reduction in range. Batteries also need to be heated in cold climates, and battery boxes insulated. I imagine the problems are similar to those in ICE vehicles (which also require a battery for starting), and can be overcome.

    All that Hydro sounds great. Australia is rich in solar energy, but this is difficult to tame on a large scale. Unfortunately we are (perhaps too) rich in coal and gas, which doesn’t make much incentive for developing large scale renewable technologies.

    It’s very hard for any one person, country or technology to provide a complete global solution. These are tough, multidimensional problems. I am content just to chip away at one area, for example advocate EVs and let others handle the issue of large scale power generation. It’s a small step in roughly the right direction.

  6. Hi David
    Interesting read, im graduating as an engineer this year and have been looking for a project to occupy me away from work and was considering converting a motorbike to electric. I dont have alot of experience with electronics however so Im wondering how you went with that.

    Also seems you went the lead-acid route, did you attempt to find any info on prices for li-po’s at any point? I imagine that the loss of weight plus the higher energy density would have been pretty beneficial.

    As an aside im from Adelaide too so its good to see there are other people in the area attempting it.


  7. Hi Ryan,

    Well all my prices are a year out of date now, as I started my conversion this time in 2007. Lipos might be affordable for a small project like a motorbike, I understand they are a bit more pricey than the Thunderskies and lead acid (but have longer life).

    If you are in SA come along to the AEVA meeting on Tuesday 25 November.



  8. I had planned to do exactly that, its where I found your blog :p

    Finish exams on saturday so should have plenty of time to tinker after that. Might see you there.


  9. Sounds really cool! How far would you be able to travel on one “charge”? Can you use a spare battery or something in emergency situations?

  10. With regular metro stop-start 60 km/hr metro traffic about 45km. However I think with different batteries I could get 60-100 km.

  11. In many places with constant sun this would be a great idea. Probably not so much in the Northern Hemisphere in the Winter Climates and Rain Forests.

    Have you seen the Rasor Hybrid?

    According to their research 75% of drivers commute less than 40 miles a day! And what is so cool about their technology is they are doing it in a Full Size SUV. So there really isn’t a downside for 3 out of 4 people!

    So many people bash large vehicles because they assume they are wasteful. But they are only wasteful if there is a single driver. If you are moving several people at once they become more economical and effiecient than a small vehicle with a single driver.

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