Australian Student Invents Affordable Electric Car Conversion Kit. - Slashdot

Posted by EditorDavid

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  Auto gearboxes dont like being towed because they require fluid to be pumped around else gears start grinding pretty soon. This applies even when they're in neutral. So if this thing simply pushes the car along and doesnt power the gearbox fluid pump the driver will be in for a very expensive and unpleasant shock soon after.

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    In the vast majority of cars the brakes do not have the vaccuum reservoir to keep applying the hydraulic pressure and there would be no power brakes, manual brakes are quite hard to use and are more of an emergency measure. Looks like it’s more like a version of the biking assist motors where the electric motor is not powering the vehicle without the original engine. Downside is it does not make the car more reliable, up side is increased horsepower and less load on the engine presumably making it

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    Auto gearboxes dont like being towed because they require fluid to be pumped around else gears start grinding pretty soon.

    I think that's only true of automatic transmissions. (Manuals have the gears and shafts immersed in oil. Automatics require the oil to be pumped, to provide power for the logic and actuators to lubricate some shafts/beraings that require oil injection because they aren't immersed, and to circulate it through an external radiator and/or heat exchanger in the engine coolant radiator (whi

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      The problem is when a manual is in neutral, the lower gear shaft does not spin and bring oil up but the top gear shaft that’s not engaging is still attached to the spinning drivetrain so it results in a lack of lubrication issue.

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        I think that's only true of automatic transmissions. (Manuals have the gears and shafts immersed in oil.

        The problem is when a manual is in neutral, the lower gear shaft does not spin and bring oil up but the top gear shaft thatâ(TM)s not engaging is still attached to the spinning drivetrain so it results in a lack of lubrication issue.

        OK, I see how that would be a problem. (I thought they had both (sets of) shafts immersed and/or had a "gear" that was always turning and at least partially immersed,

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          I’m sure it depends on the model.

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      Also you'd need to have (or add if not present) the oil cooler radiator on either type of auto transmission car - as with a "dingy-capable" vehicle (one that can be towed behind an RV with all wheels rolling and doesn't accomplish this using wheel-locking hubs.)

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      Yes that's what he just said. "Autos" and "auto gearboxes" means automatic transmissions, unless you are American, where it is short for "automobile":-) A translation problem.
      Also here, gas means gas, usually propane, not gas-oline.

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      >So this conversion looks like it would work on a manual or a rear-pump auto transmission, but would also need an extra electric tranny fluid pump on a front-pump-only automatic transmission.

      Or any 4WD vehicle. Which Aus has a lot of.

      Just put the transfer case in neutral like you were going to be towing it, then neither set of axles would be connected to the transmission at all. Doesn't matter what transmission you have then.

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        "Or any 4WD vehicle. Which Aus has a lot of."

        Why do they need 4WD in Aus? They don't have winter down there with snow and ice on the roads.

• by Travco ( 1872216 ) on Saturday October 14, 2023 @04:52PM (#63925257)

  Okay, it's a stretch for me to believe you could make four Motors capable of powering a car at a reasonable speed for that kind of price. And you absolutely can't make me believe that you can wire it and add a battery for that price. Somebody needs to check and see if he's wearing his jammies cuz I think he's dreaming

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    Yes, same here. Methinks "design" student is not an engineer. Sometimes you can make engineering like this cheaper by a factor of 1.5 or even 2. But 10x? That is just fantasy. If it sound too good to be true, it basically always is.

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    if it means I can travel, say, 120 freeway miles on 3 gallons of gas in my van and gives me all wheel drive as a bonus I'd think about adding the motors just to the front wheels. Bonus points if it gets me regenerative braking around town.

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    Two motors. They have to be tied into the frame, so you can't readily mount them on the wheels that steer.

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    Especially a battery that claims 100 km of range.

    This is obviously bogus.

• current electric car conversion services, which Burton estimates cost AU$50,000 (£26,400) on average and so are often reserved for valuable, classic vehicles.

  If you have a valuable or "classic" car the last thing you are going to want to do is butcher it into a half assed DIY BEV.

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    That's not what this says. This says conversions are usually reserved for classic/etc cars because they're the only ones worth doing it for. This half assed ones would be for more normal vehicles.

    • by Kernel Kurtz ( 182424 ) on Saturday October 14, 2023 @05:16PM (#63925289)

      Actually my comment was meant to apply to the $50K conversions as well. People with valuable classic cars who want an EV can generally just buy one. No matter how much you spend on a BEV conversion, it won't be valuable or classic afterward.

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        The high-end conversions might be an exception to that:

        https://www.driving.co.uk/news... [driving.co.uk]

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          Fair enough. When you get into that extremely rarified air all bets are off. In any case it's not really an Aston Martin anymore though, just like Tesla roadsters are not Lotus Elises.

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      You'd have to be extremely rich and not give a flying fuck about preserving or the value of a car like that in order to do this. There's a reason why cars with the original numbers matching engine are worth more than one with a replaced engine. Chopping it up and turning it into an EV would completely ruin a classic cars value. At that point, just get a kit car and make it an EV from the ground up. Or would adding braille to the forehead of the Mona Lisa make it better so the blind can enjoy it too?

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        There are lots of classic cars out there that aren't particularly valuable. I had a 1966 Pontiac Tempest in the 1990s. Engine had been swapped, transmission had been swapped, body and interior were in "OK" shape, but nothing to get excited about.

        Someone who knew what they were doing could have turned that into a decent classic car, but it would never be "valuable" in the sense that you are using. If I still had it today, I'd probably consider doing a DIY conversion by swapping the engine with an electric

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    Classic and valuable are not mutually exclusive. Classic cars are 20 years and older so a 2001 Hyundai is now a classic.

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      We clearly have different definitions of classic, I don't consider age the sole attribute. It's actually kind of scary to think about it that way - all those classic cars I used to own LOL.

• Burton believes he'll be able to offer the product for around AU$5,000 (£2,640)

  Google says that's $3,200 USD at today's exchange rate.

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    Yes, our dollar has been falling in value since July.

    If any of you were thinking of a summer vacation in January, come visit!

• I used to wonder why EV's aren't made with 4 separate motors at the wheel hubs. It seemed like a natural to me.

  Apparently there are issues with using them, see: https://evcentral.com.au/why-d... [evcentral.com.au]

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    Because hub motors involve a lot of compromises to efficiency, to the point that 1-2 bigger motors going through a single speed transmission is still cheaper and more efficient.

    Basically, with a hub motor you're making the "shaft" a lot larger than ideal, and "natural" motor rotation speeds are also a lot higher than what you want at the wheel. Fixing this costs money and weight.

    And yes, they do take extreme beatings, much more than a motor mounted to the frame.

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      The article linked by GP includes two other important considerations: finding a place for the brakes because friction braking is still required, and dealing with all that extra unsprung mass in the wheels.

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        The unsprung weight, as long as you’re not talking about rotational inertial moments like a flywheel, aren’t too big a problem. Most cars already have a solid rear axle to lower costs and you have the entire axle, differential, and part of the driveshaft on it too and it’s not that bad. Additional weight from the motors isn’t going to add much when you can get 5 horsepower per pound. The greater inertial moment would probably be noticeable but wouldn’t be crazy because axi

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    Back in the early 2000s a Japanese company was building prototypes using one motor per wheel. The head engineer said once he started doing research he found Ferdinand Porsche had patents and drawings for this design dating back to the 1930s. Rivian trucks have one motor per wheel.

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      As an available option. One per axle is the baseline configuration. Either way, the motors are not mounted in the wheel hubs.

      I'll know when Rivan is ready for the big time [wikipedia.org] when they offer a 6x6 with portal axles.

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      > Rivian trucks have one motor per wheel.

      Rivian's motors are still inboard, using a reduction gear and driveshaft to put the power to the wheel.

      These are hub motors; the motor is put at/inside the wheel and drives it directly. The major difference is now the motor becomes "unsprung mass" because it's on the wheel side, rather than on the body side, of the suspension. This is a bigger detriment to safety and performance than most people realize.
      =Smidge=

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    I found the information to be partly outdated in that axial flux motors clearly have the power density to easily power a wheel at high torque without needing a large diameter or too much bulk to achieve the high toque. All the other grievances are correct which is why you mount them on the frame and use cv joints just like traditional vehicles distribute power in the front end. You could even have a solid rear axle as well to save money. That would do away with all downsides but cost. The performance c

• To get 100km electric range, you need at least a 15kWh battery pack (~divide by 6, and remember this is going in a car that still has the weight of the engine and normal tires)

  A 15kWh home battery backup costs about AUD$15000.

  If he's selling them for AUD$5000, it's worth buying them for the batteries and the charging circuit. Sell the rest of the parts on eBay, and use that to buy a decent inverter. Poof! Whole home battery backup at a third of the price.

  Unless, of course, he can't actually sell them that cheaply...

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    A 15kWh home battery backup also includes the charging system, inverter, and everything else. A quick google shows that I can get a 1.2kWh lithium-ion battery for $280. $233/kWh. 15kWh would thus cost $3,500, or $5,566 AUD. I can get a 5kW powerwall for $1,690, x 3 = $5070. I don't think that you're going to be pulling the batteries to sell them at those prices.

    That said, the summary is wrong. Reading the ACTUAL article, he proposes a FIVE kWh battery, saying that they can stuff "3 times that into the

• This looks like a lot of added "un-sprung weight", ie, weight directly against the road not carried by struts. It's generally bad for the handling of a vehicle. Why are super-light alloy wheels a thing? That's why.

  Then of course there's the power steering, power brakes, anti-lock brakes, etc. You can drive a car without these but it's a handful to say the least, and probably not permitted in many areas. I used to roll my mustang with the engine off down a gravel road in the woods once in a while. It w

• It's a popular model internationally, but particularly in India, so I think there's like a billion of them.

• Seriously, you remove almost nothing?
  So you're converting a 3500 lb car into a 5-6000 lb car?

  You understand why this is a Bad Idea right?

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    Why would you figure the system would weigh 1500 pounds?

    The article mentions he planned on 5kWh(the summary on slashdot is wrong), 2hich would be around 200 pounds. Even 15kWh would just only be around 600.

    That shouldn't be enough to require much adjustment. Though maybe stronger springs if you really want.

    • Re: And it weighs how much

      5kWh is not going to get you very far.

      I'm worried about those flux motors. If those flux capacitors blow we could all be sucked into a worm hole.

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    So it weighs as much as a typical F150 then. https://media.ford.com/content... [ford.com]

• It can't be done with good range.

  I think there's room for a rear hub motor parallel hybrid kit, though. That would allow electrifying a typical mass market FWD car in a way that doesn't require messing with the rest of the car. You tap into its systems only so that you can read its sensors. That would require relatively little battery to provide a significant improvement, and is more realistic than lugging around the gasoline engine and just not using it which is impractical for lots of reasons which are al

• The article claims "the design is in its early stages" (and he hasn't even built a working prototype) so there is no way he can know what it will actually cost to make this.