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Pulled out of Exeter services after an 80% charge on return from Cornwall with a string of M5 rapids to choose from and soon arrived behind a very tall artic box trailer. There were lots of big trucks as it was a Tuesday.
It was 22C outside and we had decided to run the aircon when possible to stay fresh on our longest journey so it was set to a more comfortable 19.5C.
The BBC forecast was for 8mph N.Easterly so almost dead in to wind on the M5 northbound.
I often do a short test of the wake of big draggy vehicles by dropping in behind and switching the energy screen on the Leaf and monitoring real time energy consumption. This is most beneficial when in to wind of course.
It soon became apparent that the vehicle in front had cruise control on as we settled at 59mph indicated. The flat bits showed the consumption dial hovering around the 15kw power consumption.
I have been wanting to know what benefit can be gained through sitting in an aerodynamic drag wake on a long run for some time and everything appeared to provide us with the best opportunity.
Before the armchair health and safety police chime in consider this.
If you are going slower than the trucks they all have to change lanes to pass you along with everyone else.
If the gap between you and the vehicle in front is small nobody tries to fill it.
It requires alertness and driving within your limits however given that, there is no way an artic will stop quicker than you so it is completely doable just choose a distance which you are comfortable with.
This was done out of curiosity as a learning experience to try to quantify range extension for those hopefully very few times it could prove useful.
You could say I did it so you don't have to.
How much difference did it make?
Remember
We arrived at the next charger with 4 miles on the GOM which I know would provide at least 10 more miles before turtle at this rate of consumption. I was quite pleased with that and at no time were we or anyone else in any danger. Please don't ask how close as it varies and I could have been a lot closer.
So 85 miles at motorway slow lane speed is possible from an 80% charge. That is better than 5.25 miles per kWh. I could have switched off aircon and/or put it in Eco but that would have skewed the results from my normal drive mode albeit adding another 10 miles of range to make 95 miles from an 80% charge.
Leafspy reports a 100% charge to be 19.4Kw so x 5.25=101.85 miles no reserve.
Switch to Eco mode with no aircon and 112 miles would be our best achievable motorway range using the above method. Cheaper, lighter and therefore quieter (tyre noise and reduced wind resistance) than more battery or a REX.
Clearly a fair bit better than 1 mile per % is possible even for an unwashed but much loved Gen 1 in the dry.
Time to run and hide

.
It was 22C outside and we had decided to run the aircon when possible to stay fresh on our longest journey so it was set to a more comfortable 19.5C.
The BBC forecast was for 8mph N.Easterly so almost dead in to wind on the M5 northbound.
I often do a short test of the wake of big draggy vehicles by dropping in behind and switching the energy screen on the Leaf and monitoring real time energy consumption. This is most beneficial when in to wind of course.
It soon became apparent that the vehicle in front had cruise control on as we settled at 59mph indicated. The flat bits showed the consumption dial hovering around the 15kw power consumption.
I have been wanting to know what benefit can be gained through sitting in an aerodynamic drag wake on a long run for some time and everything appeared to provide us with the best opportunity.
Before the armchair health and safety police chime in consider this.
If you are going slower than the trucks they all have to change lanes to pass you along with everyone else.
If the gap between you and the vehicle in front is small nobody tries to fill it.
It requires alertness and driving within your limits however given that, there is no way an artic will stop quicker than you so it is completely doable just choose a distance which you are comfortable with.
This was done out of curiosity as a learning experience to try to quantify range extension for those hopefully very few times it could prove useful.
You could say I did it so you don't have to.
How much difference did it make?
Remember
- Gen 1 down to just under 60Ah capacity battery
- In Drive mode
- Aircon on
- Into an 8mph head on wind
- Started with a standard Ecotricity charge of 80%.
- Indicated speed 59mph - occasionally 62mph on a few downhills so about 60mph average.
- No elevation change from start to finish.
- Cruise control used the whole way +1 -1 etc.
We arrived at the next charger with 4 miles on the GOM which I know would provide at least 10 more miles before turtle at this rate of consumption. I was quite pleased with that and at no time were we or anyone else in any danger. Please don't ask how close as it varies and I could have been a lot closer.
So 85 miles at motorway slow lane speed is possible from an 80% charge. That is better than 5.25 miles per kWh. I could have switched off aircon and/or put it in Eco but that would have skewed the results from my normal drive mode albeit adding another 10 miles of range to make 95 miles from an 80% charge.
Leafspy reports a 100% charge to be 19.4Kw so x 5.25=101.85 miles no reserve.
Switch to Eco mode with no aircon and 112 miles would be our best achievable motorway range using the above method. Cheaper, lighter and therefore quieter (tyre noise and reduced wind resistance) than more battery or a REX.
Clearly a fair bit better than 1 mile per % is possible even for an unwashed but much loved Gen 1 in the dry.
Time to run and hide