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Thread: Finally an electric bike that ticks all the boxes?

  1. #31
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    Quote Originally Posted by bogan View Post
    shit that sounds high, don't spose you got those studies etc handy?

    still even at 30% to wall losses battery is much more efficient, 70% makes it to wall, 90% to batteries, 80% to wheel. When combined it's about 50% efficient, compared with 30% if you're generous for ICE, gives you an extra 60% more output energy for a given input energy. Sounds good to me
    Jantar has posted all the figures previously. I'll be buggered if I'm going to look for them.

    You're ignoring the energy that goes into getting fuel out of the ground to power power stations and you've confused battery efficiency with motor efficiency. If you had an uninterupted flow of electricity to the motor at a constant input what you say is true. However with a battery you get range or performance. Not both.

    NZ is relatively unique in that a large percentage of our power is hydro generation.
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  2. #32
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    Quote Originally Posted by James Deuce View Post
    Jantar has posted all the figures previously. I'll be buggered if I'm going to look for them.

    You're ignoring the energy that goes into getting fuel out of the ground to power power stations and you've confused battery efficiency with motor efficiency. If you had an uninterupted flow of electricity to the motor at a constant input what you say is true. However with a battery you get range or performance. Not both.

    NZ is relatively unique in that a large percentage of our power is hydro generation.
    fair enough

    actually I'm equating the out of ground energy for power grid, with the out of ground energy for petrol, if anything the petrol is likely to take more surely? (though I suppose this will drag down that final range increase percentage a bit). With an ICE you also get range or performance, why is it worse for electrics?

    yup, which is pretty handy.
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  3. #33
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    Quote Originally Posted by bogan View Post
    fair enough

    actually I'm equating the out of ground energy for power grid, with the out of ground energy for petrol, if anything the petrol is likely to take more surely? (though I suppose this will drag down that final range increase percentage a bit). With an ICE you also get range or performance, why is it worse for electrics?

    yup, which is pretty handy.
    Oil is an "energy positive" source that provides more energy than it takes to extract and distribute. Which is exactly why it has been exploited so extensively. It's cheap and plentiful. Still.

    I can't remember the figures for coal but I think it is still "positive".

    Hydrogen is energy negative because it takes exactly as much energy to "crack" hydrogen from whatever it's bonded to.

    The only way to make Lithium Ion batteries energy "efficient" for vehicular use is to use nuclear energy for all electricity requirements and to have a load balanced grid with multiple power generators on diverse networks with the energy production source close to the user. Totally unlike NZ's electricity "grid" then, with it's long transmission and distribution networks and single points of failure and mixed, thermal, geothermal, and hydro electricity generation

    Uranium is another "energy positive" power source.

    Smallest commercial reactor is 350MW.

    I can't remember properly because I've been hit in the head a lot, but I think NZ's smallest power draw overnight is 110MW and you can't reduce the output of a nuclear power station so it doesn't work for NZ.
    If a man is alone in the woods and there isn't a woke Hollywood around to call him racist, is he still white?



  4. #34
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    Quote Originally Posted by James Deuce View Post
    The only way to make Lithium Ion batteries energy "efficient" for vehicular use is to use nuclear energy for all electricity requirements and to have a load balanced grid with multiple power generators on diverse networks with the energy production source close to the user.
    How do you figure that? the simple efficiency calculation I did before shows otherwise. I assume by "efficient" you mean comparable to ICE tech.
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  5. #35
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    Quote Originally Posted by James Deuce View Post
    I can't remember properly because I've been hit in the head a lot, but I think NZ's smallest power draw overnight is 110MW and you can't reduce the output of a nuclear power station so it doesn't work for NZ.
    So you use excess energy to store potential energy to be used later to produce electricity, pump water up into the hydro lakes. Though don't take this as any approval of nuclear energy - decommissioning a nuclear power plant makes the disposal of nuclear waste look easy.

  6. #36
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    Oh well, I'm in Napier with time to waste and I find this subject fascinating so let's see whatI can find.

    Quote Originally Posted by James Deuce
    Umm you do know that there is a tremendous amount of heat generated not just by the bike, but also by practically every power generation method known to man? All of the high performance electric bikes I've read about have been water cooled.
    Heat is a by-product of just about every power conversion method known to man. The difference is that petrol burns at a high temperature which by default creates heat whereas electric motors produce heat as a byproduct of their efficiency at turning electricity into motion. What this means is they have a potential to run at far lower temperatures as technology improves.

    With a little digging I found this, It's a motor that has been 'tested' (grain of salt for any press release claims from the company itself) and produces a claimed 500hp and 573Nm of torque. In 2005. The interesting bit? Not water cooled while producing that much torque for 60 seconds flat, only air induction. Not bad for something being run in a lab.

    See for yourself:

    http://www.rasertech.com/media/pdfs/...Overview_B.pdf
    (read the next ones too before you post about the specs)
    http://findarticles.com/p/articles/m.../ai_n13599491/
    http://www.rasertech.com/media/pdfs/...ick_05-web.pdf

    And if you don't believe this example I'm sure I can find others relatively easily.

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  7. #37
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    Quote Originally Posted by James Deuce View Post
    I can't remember properly because I've been hit in the head a lot, but I think NZ's smallest power draw overnight is 110MW and you can't reduce the output of a nuclear power station so it doesn't work for NZ.
    Since it would be cheap as all get out (Yeah, right) we could all just leave our lights on and every appliance on standby. Or build another aluminium smelter.

    Just wondering if all that electrically activity on this bike would shrival your gonads...
    "I don't like it, and I'm sorry I ever had anything to do with it." -- Erwin Schrodinger talking about quantum mechanics.

  8. #38
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    Quote Originally Posted by James Deuce View Post
    .....You skipped over the power loss thing a bit too conventiently. Power loss generation in transmission in NZ rates between 30% and 60% from source to wall outlet, depending on whether it jumps the straight or not.
    Sorry JD, but you are way off the mark with this.

    Lets start with generating the electricity.
    Hydro >90% efficiency makes up 65% of our generation
    CCGT plant around 56% efficiency is now 20% of our generation
    Geothermal at around 75% efficiency makes up 8% of generation
    Traditional thermal (Huntly) is 35% efficient and makes up 5%
    Wind is 10% efficient and makes up 2% of our generation.
    So the weighted average generation efficiency for NZ is around 78%

    Transmission losses average 4.4% over the whole grid. However those places closer to generation have much smaller losses, while those further away (like Kaitaia) have higher losses. The greatest overall loss is 9%. There are some individual transmission circuits that have greater losses and only carry a very small part of the load.

    Local networks by law have less than 10% loss from Grid exit point to your domestic transformer, and in the interests of economy most lines companies keep their losses down to less than 5%.

    Then your own house is limited to less than 5% loss by virtue of the wiring regs.

    So overall transmission loss from generator to socket is around 14% but certainly less than 20%.

    So now with the generation efficiency and transmission efficiency taken into account the energy stored in the battery is 67% efficient. Modern electric motors are often in the 85 - 90% efficiency range. So now that electric bike from source to rear wheel is better than 57% efficient.

    This far better than any ICE can manage even without looking and the energy lossos in pumping, refining and transporting that fuel for use.

    Edit: I've just trealised where JD is coming from with the claim about losses across the HVDC cables. They are generally less than 10% in bi-pole operation, can be up to 20% in single pole operation, and can get as high 40% in what is called round power. That latter one is a test mode, and not currently used in normal operation.
    looking at the system right now: Total demand is 4850 MW, and there is 245 MW going north on the HVDC and 239 MW received at Haywards. That is a loss of 2.4%. If the loss was curently at 20%, then 20% of 245 MW is 49 MW, but that is only 1% of the total system load.
    Last edited by Jantar; 20th December 2010 at 19:59. Reason: Spelling and clarification.
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  9. #39
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    Quote Originally Posted by James Deuce
    How is it more "efficient"? Did you not pay attention during the 4th form science class (or whatever year you whippersnappers are up to) about signal attenuation when transmitting alectricity or about the massive amount of power lost converting electricity from DC to AC like we do across the Cook straight. Battery powered vehicles are at the end of a production chain and with internal combustion engines now approaching 30% thermal efficiency I'm not convinced that they'll be usurped by electric vehicles any time soon. IC powered vehicles may use a different fuel source (equally as questionable ecologically) but they aren't going anywhere UNTIL someone comes up with a power pack to drive electric motors that gives people the same or better performance and range.
    May I humbly suggest that you have not been to school in a few years and technology moves pretty damn fast?
    Not to mention they don't teach advanced electronics in high school..

    "94-95% Efficient Across the Speed Range Using Trench Gate IGBTs and low loss free wheeling diodes"

    http://vtrux.com/motors-and-drives/p...00-controller/

    I'm just skimming google here as I'm not 100% on the search terms, but apparently this controller runs at 500-700V DC, produces 110kw (147.5hp) continuous and 215kw (288.3hp) peak.
    Sure it weighs 36kg, and the engine weighs 67kg, but 147hp is overkill anyway. Still I'll do a few calculations later.
    Will address batteries later too.

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  10. #40
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    Quote Originally Posted by James Deuce
    It "might" need less maintenance (do you not look after your suspension, your drive mechanism, or chassis bearings?) but what's worse case scenario for an engine replacement in an IC bike? $2-3k? with a bit of cunning and 2 mates you could keep it under a $1k.
    2k-3k to replace something that has been in very active development for over 100 years? Actually suprised it isn't lower. Oh wait I'm not, It's amazing that something with so many complex, high tolerance moving parts is even remotely as cheap as they have become. That's how mass production and intense competition works.

    You may have noticed that with electronics this kind of thing happens alot, only an a whole different magnitude. Your phone has more computing power than the apollo space shuttle for a good reason. And as has been proven again and again war and competition produce the fastest advancements in technology, why do you think there is an electric GP and electric motors being introduced for a 'power boost' in F1?

    Electronics can shrink, engines can't. You can't build an engine much more simply than it is now, whereas an electric system is simpler to begin with.

    It won't be perfect, nothing ever is. And all the other technology still needs maintaining, but I'm looking forward to not trying to balance four carbs or worrying about where to take my used oil.

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  11. #41
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    Quote Originally Posted by James Deuce
    Priced up a Hybrid's battery pack lately? You'd be better off replacing the vehicle. Then where do all those reare earth metals go when the batteries get thrown in the rubbish? Noticed how your Lithium Ion cellphone battery performance degrades over time? A comparatively short period of time I might add.
    I will concede this is the weak point, this is the part where we are waiting for technology to catch up with fantasy. But indulge me for a minute.

    Lets say a GSXR Weighs 170kg Dry and 200kg Wet, and the engine weighs 60kg give or take. Lets also assume the extra paraphanelia that you wouldnt need with an electric bike like petrol tank, engine mounts, ECU, coils etc weighs an additional 20kg or so (I'll admit I made this up but I couldn't find any info)

    That gives us 110kg to make up our weight back to where it was before.

    -36 for the controller - 67kg for the engine = 7kg for wires and batteries. A tough target indeed. So I won't bother, lets assume 30kg for batteries and see where we get to.
    Petrol has a Wh/kg of around 12000, that's... Alot.
    I'm going to be optimistic here and assume it's possible to buy a battery with around 250wh/kg. That would give us (250*30) 7500w/h.


    So at oure controllers maximum constant rating of 115kw we get around 4 minutes. But using 115kw will get you to 150kmh in a matter of moments..
    A Yamaha TZ750 uses 21hp to do the ton (Total Control), thats 15.66kw. So assuming the GSXR is roughly the same we can figure out that you can do 161kmh for 28 minutes. Not alot then but you will have covered 76km in that time.
    Given that this battery will take hours to charge and cost immense amounts and still weighs alot we can more or less prove that petrol is still king. For now.

    Let's try Lithium air
    http://www.batteriesdigest.com/lithium_air.htm
    The chemical reaction produces 3620wh/kg, but lets assume in a few years we can practically achieve 1000wh/kg or 1kwh/kg (as the article states)
    Our 30kg's becomes 30kwh, our 4 minutes becomes 16 and our 28 minutes becomes nearly 2 hours. In a few years we could have a (fairly) conservative cruising range of 400km even while allowing for a less than perfect drive train, a cooling system and an enthusiastic right hand. That's more than acceptable.
    If by then we can get our controller to say 15kg and our motor to 50kg we will have today's GSXR1000 squarely beaten. No idea what the 2020 GSXR will look like, though.

    Yes there is an awful lot of conjecture here and my maths is probably way off (I never was good at math) but it doesn't take a genius to see that the potential is there.

    Edit: Also forgot to include regen in the calculations, oops!

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  12. #42
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    Maybe a repost but who cares, like a never ending first gear...

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  13. #43
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    So if the power output from the motor was backed off a little it could or should have decent range as a road going bike and built into any bike style. We could even be close to seeing the first adventure bikes riding across the globe as EVs?

    We live in interesting times.
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  14. #44
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    Quote Originally Posted by SMOKEU View Post
    Electric vehicles are clearly the way of the future - but it's not really feasible until batteries can give good performance for 400km+; about the fuel tank range of most cars. The majority of people won't be happy with a car that needs to be recharged for a few hours after every 50km of driving.
    Or maybe people need to rethink what is really important to them in a vehicle. When the price point for current technology electric/cars bikes becomes affordable I think a lot of people will be using them for commuting and short-medium distance work and then have a petrol/diesel car for long distance travel.

    When I think about what I use my bike/car for I realistically only need a 100km range from a single charge, assuming I can do 100kmh sustained for 75% of that. Alternatively if you think about riding to work and then plugging in to charge then for most people the technology is ready to go already just that its a tad pricey.
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  15. #45
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    The answer to the limited range with each charge is to have standardised vehicle batteries. That way you pull into a fuel station, unclip your almost discharged battery, clip in a freshly charged battery and off you go. % minutes per stop, about the same as a fill up takes now. The cost would be the cost of the electricity to charge the battery, plus a proportion of a replacement battery. If the manufacturers are claiming 1000 charge cycles, then that would be 1/1000 the cost of a new battery.

    The first manufacturer to take up this concept will get the lion's share of the business.
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