Hackaday Prize Entry: An Electric Vehicle From Recycled Parts

In the future, just about everyone will be driving an electric car. We’re seeing the beginnings of this, and that means electrics and hybrids are showing up in junk yards. What does that mean? Tons of big batteries and powerful motors to build an electric vehicle from recycled parts.

A few years ago, someone exceptionally smart did the math on the environmental friendliness of different makes of vehicles from cradle to grave. The most environmentally friendly car to buy wasn’t a Prius, Leaf, or Tesla, but a used car; an old Civic or Rabbit. The logic makes sense – after two or three hundred thousand miles under its timing belt, the Civic or Rabbit has already paid the cost of forging the body and refining the plastic. Obviously, then, the most environmentally friendly car would be reusing the batteries and motor out of a newer hybrid.

For his Hackaday Prize build, [mauswerkz] is taking a 2001 BMW 330ci coupe and replacing the motor and transmission with some salvaged EV equipment. In this case, it’s the transmission and inverter from a Lexus GS450h and the batteries from a Chevy Volt ‘Extended Range’. Where the magical junkyard [mauswerkz] is pulling this equipment out of is anyone’s guess, but he did it. Maybe you can too.

So far, [mauswerkz] has the charger out of the Chevy Volt hooked up to the inverter and transmission from the Lexus and is making stuff turn. It’s only running at 200V instead of the final voltage of 650, but it’s enough for a proof of concept. Now it’s just a matter of stuffing everything inside the BMW.

Of course going to a junk yard isn’t the only way to get an EV. The more enterprising builder might want to build their own EV completely from scratch, starting with a block of foam. Yes, it even looks better than the BMW.


The 2015 Hackaday Prize is sponsored by:

49 thoughts on “Hackaday Prize Entry: An Electric Vehicle From Recycled Parts

  1. “In the future, just about everyone will be driving an electric car.” I really appreciate the sentiment of this: Electrics are mechanically simpler, driveability is better, etc. But, is it really reasonable to carry around a third of the vehicle mass in the form of a battery and its associated structure? It’s more rational to carry around that energy in a much more dense and more easily stored and dispensed form, like a liquid fuel (which does not need to be fossil-derived gasoline). It will refuel faster and have much greater range.

    If the electricity for (say) a Tesla comes from the typical USA production mix (i.e. mostly coal plants), it produces more carbon dioxide per km traveled than liquid-fuel cars in its size/cargo class, in part because of the extra weight of its “fuel tank”, and in part because liquid fuel produces more motive energy per kg of CO2 released than the average electric generating plant.

    1. Your comment is a lengthy explanation of what I can sum up in one sentence: Electric vehicles will likely not become mainstream until they can be operated *completely* on electricity alone *and* they don’t need to be plugged in between trips. Cover the whole car with high efficiency solar panels, ditch the gas engine and generator, and ditch the plug while you’re at it (well, maybe keep one around in case of an emergency, like jumper cables).

          1. A supercap is of some use for that 10 second burst getting on an onramp or overtaking, if your primary battery is so poorly engineered so to not to provide enough power.

            That, and they’re also excellent at reducing cargo capacity. Their volumetric energy density sucks.

      1. What you claim is impossible. Let’s do the math.

        “Cover the whole car with high efficiency solar panels”

        1 – Solar power, as in the actual maximum radiation from the sun itself, directly, is ~1000 watts per square meter (~10 square feet). Best case scenario. That means: no cloud, at noon, at the equator, when perfectly clean.

        2 – The roof of a car is, what, maybe 4 square meters at most? That means at most 4000 watts of power if you were magically converting sunlight into speed.

        3 – Solar panels, a technology that converts solar energy into electrical energy, are able to output about 15% of the solar energy striking them. So that means only 150 watts for every 1000 watts hitting the panel. So our 4000 watts of solar energy is down to 600 watts of electrical energy.

        4 – Let’s presume no cabling, controller, motor, or other losses, to be generous.

        5 – Let’s presume there are no headlights, ECU, or electrical systems onboard. For example, lights alone are probably 600 watts. You know those window-mount air conditioners for apartments? They’re 3x that much wattage. A 600 watt A/C would probably not even keep the car bearably cool at noon in full sun on the equator. 600 watts isn’t even an especially large fan.

        6 – How much power is 600 watts in terms of moving the vehicle? Well, about 750 watts are equal to 1 horsepower. So, this “car” would have no even 1 horsepower. Mopeds will have 10hp. Electric bicycles will have 0.5-1 horsepower, and they only have to move a bike.

        7 – Powered by solar, how fast could a car travel? Well, it probably couldn’t move. Rolling resistance (deformation when rotating) of the tires is probably more than that. So, let’s presume it floats on magical bearings and train rails. Let’s presume no transmission losses either. Just to push air out of the way, that car could perhaps go 20km/hr, or 13mph. As fast as a 10 year old child on a bike.

        That’s on a perfect day in perfect conditions.

        “Well technology just has to improve” you say? FINE. Fuck it. Let’s say all 4000 watts are going straight into propulsion. How fast then?

        4000 watts is 5.3 hp. So, equivalent to the shittiest little POS moped you can buy with a weedwhacker “engine”.

        How fast?

        Well, power to move through air is a CUBE of speed. As in, if you want to go 3x as fast (highway speed), it takes 27x as much energy. So, 22 hp, on flat terrain, and it takes probably 10 minutes to reach that speed.

        But nevermind, we’ve got like, 8 times as much energy, not 27x as much. So…

        45 km/hr. Or 28mph. Slower than you go on residential roads. And that’s absolute max speed that you’d asymptotically climb to. Your acceleration would be null. Think about a really crappy car (100 hp), one where you’re embarrassed by how slow it accelerates. Now cut away 80% of the power of its engine.

        In short… laws of thermodynamics prevent 100% solar from every being a useful thing.

        Which is okay, you’re not driving 24/7. Some energy storage is okay. But some energy storage is absolutely necessary.

        1. The whole world isn’t in sunny state California. Battery capacity get low and do not get charged if you are -20C, so a full EV might not be so useful for some countries. There is also very large seasonal changes in available sunlight if you are far enough from the equator and they would not pay off. Also good luck with the mud, salt spray, frozen ice, snow covering the panels.

          1. http://batteryuniversity.com/learn/article/charging_at_high_and_low_temperatures

            >Li-ion:
            >Charge Temperature: 0°C to 45°C (32°F to 113°F)
            >Discharge Temperature: –20°C to 60°C (–4°F to 140°F)

            >Many battery users are unaware that consumer-grade lithium-ion batteries cannot be charged below 0°C (32°F). Although the pack appears to be charging normally, plating of metallic lithium can occur on the anode during a subfreezing charge. The plating is permanent and cannot be removed with cycling.

      2. You are thinking of the cars we had on Mercury where the Sun is six times brighter and with no atmosphere, 18 times compared to Earth surface. But man, the seats got hot when we left the car out on the day side! I like it here better.

  2. There goes the claim that old EV parts will just sit in a landfill. The knowledgeable DIYers would go and pick out the parts like a bunch of vultures. Apart from reusing them in homemade EVs, the batteries are reusable in all sorts of other applications.

        1. 1500-2000 is the number of cycles a -new- quality lithium battery is expected to last before its capacity drops below 63%

          The increase in internal resistance and loss of lithium from the electrodes, effectively a loss of electrode area which increases current density in the non-affected areas, is a self-accelerating process, and the 63% is the knee point in the curve, after which the capacity starts to collapse rapidly towards zero over a handful of recharge cycles. The process can be somewhat delayed by reducing the depth of discharge and discharge rate, but nevertheless a battery that is discharged from use in an EV because it’s lost ~20% of its capacity is not likely to survive more than 100-20 more cycles.

          1. Real world experience with the Nissan LEAF is showing much longer battery lifetimes, likely because the battery is never fully charged or fully discharged.
            And, junkyards are full of wrecked cars that are fairly new, don’t assume the car was junked because the battery was at end of life.

          2. A cycle with lithium batteries is a full recharge cycle. If you don’t reach 100% DoD then it’s not a full cycle.

            The Leaf 24 kWh battery is limited to 21.3kWh usable and has a 73 mile range. At 2000 cycles, it’s expected to last for 164,000 miles before dropping down to 63% capacity.

            In practice, the battery’s shelf-life ends before you can drive as much on such a small battery. The battery drops down to 70% capacity in 10 years even if you don’t use it because the same wear-down mechanism occurs spontaneously whenever there’s any significant charge in the battery. A year is worth about 200 cycles.

            In other words, to get the maximum miles out of the battery, driving five days a week, you’d need to drive more than the battery can actually manage.

      1. That assumes that all the batteries are in the junk yard because the wore out. Many batteries will be in the yard due to accidents, or because some other expensive part failed. (“oh your charger just failed. $5000 for a new one? f’it I’ll just get a new car!”)

          1. There are now many wrecked Nissan LEAFs that have been sold at auction without catching fire. This include some that appear to have been under water after Hurricane Sandy.

          2. Replying to Bill’s reply to this ^^^ but for some reason no reply button on his post…

            An EV battery (or any electronics) that’s been underwater would not be a great purchase, would it?

            I know you can dry your phone out if you drop it in a puddle, but #1 thing is to remove power ASAP, whereas a battery (or whole car) that’s been underwater will have power present which encourages all manner of faults, shorts, and muchos electrolytic corrosion. I’ve seen good quality electrical gear disintegrate into a ball of green fluff (copper corrosion) after being moist whilst powered for ~48hrs max.

  3. IN this days, at least here, it is cheaper to buy the battery cells from the internet each one, and assemble them than pay for it in a junk yard, plus new battery is always new.. The eletric motor and controller may not be the cheapest thing in the earth but it is more than the batteries, though you might get one a little cheaper in the junk yard..

  4. Maybe some day electric cars will take off and be mainstream, but for me, nothing beats hearing an actual engine, and being able to shift through the gears. It really gives you the feeling of being in control of the car. also, electric cars destroy all possibility of customizing your car and it’s drivetrain. I know that electric cars have their place, but for me, at least for now, I like normal cars powered by decomposed dinosaurs.

      1. …I would. Actually looking at going back to a motorcycle with a kick start and dropping batteries. Granted, I’d probably have to rig some sort of ratchet and pawl spring winding device to unload all my kicks at once into a car/truck engi……

        …Say, that’s not a bad idea.. CRAP. Now I actually want to build one.

        1. Large engines used to be started with smaller engines, which were started by hand.

          But I don’t see the point. There’s no more “control” in starting with a hand crank over an electric starter. The engine starts or it doesn’t.

          1. Eh. No real point to it. I had to roll start my motorcycle for about 2 weeks once because of a dead battery. That’s all that got me thinking about it.
            Just this whole thread got me thinking of crazy things to do with larger motors. It’d be interesting to see how hard it would be to take, say a mechanical fuel injection diesel motor and find a way to overcome all that compression to manually start it. See how far in the opposite direction of an electric vehicle you could go. Just for ‘kicks’ as it were.

          2. Pirate Tom: It wasn’t *that* long ago that diesel engines were started with 12-gauge shotshell blanks. These pre-war machines (road equipment, dozers, etc.) were *entirely* without electrical components.

            It’s also straightforward to open the exhaust valve of diesel (like a Jake brake but timed earlier) or have a compression release valve to let it free-run under no compression to get it up to speed, then close the valve to start it. Many stationary diesels operated this way.

  5. >after two or three hundred thousand miles under its timing belt

    Putting more that 100k miles on a timing belt is a great way to not have an engine in another 50k miles. Belts wear out, and letting that happen with the one that keeps your piston heads from colliding with the valves and destroying both is definitely neither environmentally nor wallet friendly.

  6. Apparently NONE of you people have converted a car. I have. I am also running Volt batteries that are 6 years old. Havent had a meltdown or anything yet exciting, well, except for that pesky plasma wrench incident.

    Do the MATH. THINK a bit. Then go ahead and troll all you like.

  7. While I applaud the DIY mentality of building your own EV car, the fact is that the writing is on the wall for ‘owning’ your own car. Insurance, registration and parking in major urban areas isn’t getting any cheaper not to mention road maintenance costs and such. Most young people these days aren’t interested in working on cars only driving them for short periods of time. The Cars To Go Model is the most likely scenario for the future of cars.

    1. And it’s probably going to be the end of cars, since only the rich can afford to drive.

      Most of the working population drives third hand cars that are close to their end of life, or already at it but kept going with duck tape and chicken wire. Any sort of rental car scheme can’t compete with that on a cost per mile basis because there’s some minimum standards they need to maintain, plus the service overhead and profits.

      So if people are forced to abandon old cars, most people are simply forced to stop driving.

  8. I’ve been driving my 1981 vw diesel rabbit for over 25 years now, it has almost 350,000 miles on it and has consistently maintained 49-50 mpg on the highway. It can run on different fuels and currently is running B20. I’ve run it on petroleum based diesel, homemade biodiesel, waste vegetable oil and used filtered motor oil. The cost per mile is dirt cheap and the emissions are mostly particulates of carbon and every time I run it through emissions testing I pass with flying colors. For me this has been the perfect vehicle.
    That said, I believe the future of transportation is not in internal combustion engine technologies, its only a matter of time before 2 things happen.
    1) people get over range anxiety and realize 100 mile range is just fine for most everyday usage.
    2) The really smart people that make up communities like Hackaday will help to create transformative technologies that move us on to something better.
    While we may not be driving pure electric cars in the future, I believe electric vehicles will lead the way away from internal combustion engines and on to something much cooler.

    1. Range anxiety isn’t about getting through your daily driving, but about the knowledge that if you should need to get anywhere in a hurry, like in an emergency, you can’t because you’ve already gone through your allotted miles for the day and can’t get any more without waiting 6-12 hours.

      The bigger problem is on the supply side, because an electric car consumes about as much as an entire household in a year. That forces utility companies to limit how fast you’re allowed to charge, because they can’t deal with arbitrarily high peak demand in neighborhoods. The grid just isn’t built for that, and you don’t want to pay them to upgrade it for that.

      So, the utilities are forced to restrict how much you’re allowed to recharge per day. The average American household draws about 11 MWh a year, so if they cap the demand at 2x the current level, that’s going to limit your daily travels to about 80 miles a day.

      80 miles a day is not much. Its 40 miles out, 40 miles in.

      1. Plus, there’s another problem with the electricity supply due to the shift to renewable energy.

        People are supposed to be start using renewable electricity instead of gas for heating and cooking etc. and the average household is actually using more like 20-30 MWh of energy a year all accounted for. In California it’s about 18 MWh a year, in Seattle or Chicago it’s more like 28 MWh/a.

        So the pressure on the supply grid in the future is going to increase massively even without the electric cars.

  9. “Obviously, then, the most environmentally friendly car would be reusing the batteries and motor out of a newer hybrid.” Basically this sounds like a gain by increasing the miles you get from the manufactured components, minus the energy it takes to dismantle scrap and build the recycled car, new (used) tires, etc. I think it would be “greener” to buy a car like the one the parts come from and drive it as many miles as the wrecked one + your expected recycled car miles. So, no. I am guessing recycled is not the greenest.

  10. The techie in me wants to say I admire his enthusiasm, but the realist in me wants to say that putting all that weight into an already heavy E46 is crazy. Plus the fact the the M54B30 is a wonderful, well powered, low maintenance, good economy engine, that will easily last 200K miles with proper care.

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