Maximising Range in a ZOE

A guest post by Nosig

Maximising Range in a ZOE

Figure 1: ZOE energy consumption and range at different speeds (Image: Nosig)
Figure 1: ZOE energy consumption and range at different speeds (Image: Nosig)

When looking to maximise range in an EV, slow speeds are very good since air drag is very low. It increases exponentially with speed. Accelerating harder is not good for efficiency, you trade energy for time. Regenerative braking is never going to be perfect, but the regen on the Zoe can actually charge up to quick-charger speed. If you want max efficiency, let it roll out as much as you can as long as possible. That will enable fewer miles driving under power while regenerating on those same miles.

For the best range ride smooth: accelerate slow and smooth, drive slowly, try to get maximum regen time (so a loooong roll out) if you know you have to slow down, and try to avoid stop and go since the acceleration (and slight loss on decel) will take extra energy. Still it might be better to have a slower route with traffic (bit stop and go), than having a smooth cruise at higher speed, since air drag will be the real killer. Smooth and slow are the keywords for max range.

I have made two graphs with some consumption numbers on the same road with identical circumstances. The absolute numbers are not that important (they change with slope, temperature and wind), but it’s just to show the huge relative influence of speed (thus drag) on consumption and therefore range (in km and km/h). Theoretically, if you constantly drive at bicycle speed, you should be able to drive from the UK to the Côte d’Azur on one charge (see Figure 1).

The assumption here is that the road is constant, level, speed is constant, nothing changes and the indication is more or less accurate. I also assume the full 22 kW is used for range. In this case the air-conditioning was on, but I hardly see any difference in consumption with the airco off. I actually noticed a constant 1 kW/100km consumption at 30 km/h, which would give a theoretical range of 2200 km, but that would distort the graph too much so I changed it to 2 kW/100km.

The thing to learn is the constant exponential increase in consumption, so best speed is the slowest and the increase in range can then be huge (2200 km in theory) as can the penalty with higher speed. A constant 140 km/h would drain the battery completely in about 50 km / 30 miles (!).

A gasoline/petrol car might be able to have a range between 700 and 900 km depending on riding style and circumstances, the Zoe can in theory have a range between 50 and 2000 km. It just indicates that it’s extremely hard to compare range figures with gas cars – it’s a whole different game.

Home Forums Maximising Range in a ZOE

This topic contains 8 replies, has 6 voices, and was last updated by  yoh-there 2 years, 10 months ago.

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  • #4628

    Trevor Larkum
    Keymaster

    Maximising Range in a ZOE, by Nosig. When looking to maximise range in an EV, slow speeds are very good since air drag is very low. It increases exponentia[See the full post at: Maximising Range in a ZOE]

    #4631

    Nosig
    Participant

    I still would love to make a blogpost for you (next week or so), this post links to itself?

    #4643

    Trevor Larkum
    Keymaster

    I had a go at making your forum posts into a new blog post for the home page of the website (just with light editing). That way I can follow it with a couple of my own posts on related subjects. Note, you may have seen it while I was still editing it.

    I hope you’re happy with it (however if you’d rather it was taken down and replaced, just let me know). Note, leaving it up doesn’t prevent us from adding longer or more detailed posts later.

    #4646

    Nosig
    Participant

    It seems to work now, fine like this. Can indeed always add stuff.

    #12550

    Harm
    Participant

    I see you use several times kW/100km, and when you talk about the energy in the battery you say 22kW.
    I think you mean kWh/100km and 22kWh.
    This mistake is made very often in articles, but it really means something different.
    Power (P) has unit W or kW.
    Energy (E) has unit Wh or kWh.

    #25286

    yoh-there
    Participant

    Here are a few extra tips on how to avoid friction braking using CanZE and the recently added “aiming bar”.

    http://canze.fisch.lu/interesting-question-about-the-torque-ar/

    Please note this assumes braking is needed. In my opinion coasting (basically rolling out in neutral) is even better, as it avoids the regeneration losses completely.

    #25351

    Samsam
    Participant

    I’m always coasting in neutral

    #25401

    sandy
    Participant

    I tried coasting in neutral on my epic road trip to Manchester. I saw little to no improvement on range over balancing the throttle in that sweet spot where your using no power.

    That said, slotting into neutral is easier, but the Zoe being so heavy will pick speed up alarmingly quick going down hill in neutral, so you need to pay attention to speedo.

    #25402

    yoh-there
    Participant

    It would be extremely unlikely for N-driving to perform better. After all, the net effect is exactly the same, assuming one has a steady foot. Personally, I simply find it a lot easier to do N-driving as opposed to “aiming the throttle to the 0-kW-point”.

    Depending on how steep your downhills were, the driving screen (and soon the braking and consumption screen too) in CanZE has an “aiming the braking pedal to avoid friction” bar. No N can help you there. Another little tool to save a few joules. That bar’s value BTW, comes straight from the car’s computers and includes effects such as a full battery, temperature effects, low RPM, high speed, etc.

    It would be nice if the setpoints for i.e. coasting friction could be user-changed in the car’s computers. One can wish….

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