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What is the most commonly used unit of consumption on EV?

  • 20-07-2020 5:35pm
    #1
    Registered Users Posts: 17,648 ✭✭✭✭ Cyrus


    km/kw?

    100km/kwh?

    or what :D


Comments

  • Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 6,072 Mod ✭✭✭✭ liamog


    In European markets Tesla tend to go for Wh/km, other manufacturers prefer kWh/100km.
    It's easy enough to convert between the two. 156Wh/km is 15.6kWh/100km.


  • Registered Users Posts: 2,716 ✭✭✭ Silent Running


    Recently I've taken to using Kms/kWh. I just feel more comfortable keeping an eye on my range/efficiency with this measure.


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,823 CMod ✭✭✭✭ unkel


    We really should be using one measure when comparing cars: kWh / 100km (are you listening Tesla, Nyland?)

    A lot of EV owners use a little rule of thumb for determining their own range, but that's usually based on percentage SOC. In Ioniq classic it's roughly 2km left per percentage point. In my Tesla Model S it is 3km (motorway at 120-130km/h) or 4km (non-motorway). Original Leaf owners typically use 1km per percentage point

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



  • Registered Users Posts: 1,460 ✭✭✭ innrain


    The practicality of the new units should be given by what you use. In this case you are billed for kWh and so it is natural to use that -> kWh/100km. Direct comparison to l/100km from the ancient times.

    Silent Running this works for your car but if you want to compare to other cars things are not linear

    supposed three cars: one does 5 km/kWh, one 6km/kWh and the one 7km/kWh. If they drive the same distance lets say 1000km the first one requires 200kWh the second one 166.7 kWh (33.3 kWh less) and the last one 142.9 kWh (23.8 kWh less from the second).

    sorry I'm a nerd. :)


  • Registered Users Posts: 10,919 ✭✭✭✭ Calahonda52


    kWh/100km is best as it can be compared with l/100 km as petrol is c 9 and diesel is 10 kWh/litre

    so if the ICE is doing 5l/100 = 50kWh/100 = 6 euro/100

    My Leaf is about 14/100 = at night rate is about 1.5 euro/100


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  • Registered Users Posts: 2,716 ✭✭✭ Silent Running


    innrain wrote: »
    The practicality of the new units should be given by what you use. In this case you are billed for kWh and so it is natural to use that -> kWh/100km. Direct comparison to l/100km from the ancient times.

    Silent Running this works for your car but if you want to compare to other cars things are not linear

    supposed three cars: one does 5 km/kWh, one 6km/kWh and the one 7km/kWh. If they drive the same distance lets say 1000km the first one requires 200kWh the second one 166.7 kWh (33.3 kWh less) and the last one 142.9 kWh (23.8 kWh less from the second).

    sorry I'm a nerd. :)

    The thing is: I only use the measure to assess my efficiency in real time, and I find Km /kWh best for that at the moment. It's a personal thing and I don't use it for anything but that.

    Using any consumption measure to compare isn't practical anyway, unless you're using the same driver, on the same route, in the same weather conditions and with the same load. It's all just guesswork to a point.

    For me, it's all about guessing how far I can go on any given battery charge state before I need to charge. I've used kWh/100Kms for a couple of years, now I'm trying it with Kms/kWh.


  • Registered Users Posts: 1,008 ✭✭✭ ei9go


    If you assume that you will get about 6 kms per kWh, it's an easy way to think about your journey. You may get worse and you will often get better.


  • Registered Users Posts: 17,648 ✭✭✭✭ Cyrus


    ei9go wrote: »
    If you assume that you will get about 6 kms per kWh, it's an easy way to think about your journey. You may get worse and you will often get better.

    in an etron, be closer to 4

    :P


  • Registered Users Posts: 2,716 ✭✭✭ Silent Running


    ei9go wrote: »
    If you assume that you will get about 6 kms per kWh, it's an easy way to think about your journey. You may get worse and you will often get better.

    Yes, but on a long journey, the assumption can mean either a trip on the back of a flatbed or an extra unnecessary charge stop. I prefer getting it right. I can then make corrections on the fly if weather, traffic or the unknowable intervene.

    My long journeys are planned with slim margins to avoid making the trip longer than necessary. :) It hasn't let me down yet. :cool:

    For normal running around, I just wing it. :D


  • Moderators, Category Moderators, Motoring & Transport Moderators, Regional East Moderators Posts: 58,823 CMod ✭✭✭✭ unkel


    For normal running around, I just wing it. :D

    It's handy when you have car that has such a big battery that when it says just 10% left you can still make it to the other side of Dublin and back :D

    "Wind is Ireland's oil" - An Taoiseach, 25/05/2022



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  • Registered Users Posts: 17,862 ✭✭✭✭ ELM327


    In Ireland it's generally kWh/100km or wh/km.
    In the UK they are using miles per kWh.


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