In this short series of posts, I'll cover the basics of running an electric vehicle (EV) instead of a petrol or diesel vehicle - an important step in the transition away from fossil fuels. In this post, we are looking at range.
Electric range is the total number of miles an EV can go without having the charge - usually from 100% charge to 0% charge. It is based on an electric consumption figure achieved in a test that all cars do (called WLTP). A petrol or diesel car has the same figure - however helpfully for consumers, it is just not used in marketing for those types of car. You can work it out fairly simply though...
What do you mean?
To bring it to life - let's take two example cars, one petrol and one electric. Now I appreciate there are more and less efficient examples of both car types - but this is primarily for comparison purposes - just like the WLTP test itself.
Car | WLTP rated efficiency | Comparable efficiency | kWh size of fuel tank/battery | Fuel tank size (equivalent to petrol) | "Range" 100% - 0% |
Petrol | 30 mpg | 0.7 miles / kWh | 445 kWh | 50 litres | 330 miles |
Electric | 4 miles / kWh | 160 mpg | 77 kWh | 8.7 litres | 308 miles |
Now, if you are anything like me - you may be shocked by some of those figures. But I think this way of looking at things highlights two key points. 1) Petrol is very energy dense. 2) EV's are more efficient than you thought.
Amazingly, a 50 litre tank of petrol is the equivalent of having a 445 kWh battery pack.
So even with a comparably tiny fuel tank - an electric vehicle can achieve a similar range to a petrol car. Also, don't forget - car battery technology is in it's relative infancy. Car manufacturers have been working to make petrol engines more efficient for over 100 years - whereas most have only just started making electric cars. Expect big things here - both in terms of battery density and also electric car efficiency.
The comparable efficiency shows the electric car is 533% more efficient - and thus uses over 5 x less energy to drive the same distance.
Mind blown?
Ok, now that's done, let's talk real world range. Taking the example above - the rated range (from the WLTP test) is 308 miles. Are you going to get 308 miles from 100% charge then? Well no, no your not. Firstly, you probably aren't going to use 100% of your charge - just like you probably wouldn't in a petrol car either. You will likely re-fuel at between 5-20%. Second - as with a petrol car, you are very unlikely o achieve the WLTP rated miles / kWh. But as it uses the same test, you are likely to see the same results - but with perhaps slightly worse performance during winter (batteries aren't a massive fan of the cold). So to cut a long story short, you are going to likely to see between 70-80% of the rated range - and perhaps as low at 60% in winter.
Let's look at an example of the real world range of a 308 mile range EV
Drivng style (% of WLTP rated range - 308 miles) | Range from 100% - 5% | Range from 80% - 5% |
Driving like an EV pro + Summer (100%) | 293 miles | 231 miles |
Driving like an EV pro + Autumn/Spring (90%) | 263 miles | 208 miles |
Driving sensibly + Summer/Autumn/Spring Driving like an EV pro + Winter (80%) | 234 miles | 185 miles |
Driving sensibly + Winter Driving like a petrol car + Summer/Autumn/Spring (70%) | 205 miles | 162 miles |
Driving like a petrol car + Winter (60%) | 176 miles | 139 miles |
So the real world range of a 308 mile range EV is anywhere between 293 and 176 miles - depending on time of year and how you drive.
But why have you shown two ranges?
The WLTP rated range is from 100% to 0%. As I've already mentioned, you are very unlikely to drive until you reach 0% - so 5% is more realistic for as far as you'd probably go before you charge up. Secondly though, most EV's recommend that you charge them up to 80% - rather than 100%. Without going in to too much detail, this is basically to help look after the battery and will hopefully make it last much longer. The other reason you may only be at 80% is because if you are on a long journey of maybe 1000 miles - you won't be charging to 100% at each stop because of the fact that charge speeds reduce rapidly beyond 80%. So for this reason - I've included a second column from 80% own to 5%. This gives slightly lower figures of 231 miles to 139 miles depending on time of year and how you drive.
This is complicated...?
Maybe - but don't forget, as I mentioned earlier this is all relatively new. I wasn't around but I suspect when petrol cars were introduced, people had the same problems - just without all the technology in the car to support.
In Tesla cars, they have even developed an "app" in the car to help better understand range. The "energy" app will highlight how you are performing against the rated range of the vehicle - and identify where you've under or over performed. Areas it highlights include, excessive acceleration, motorway speeds of over 70mph, gradient (one way journey going uphill), air conditioning, sound system etc. It tells you exactly how much everything used and therefore what impact it had on your total range...clever huh?
If you have any thoughts, feedback or ideas you wish to contribute on this or any other topic covered by The Climate Coach - please get in touch, we'd love to hear from you.
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