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Discussion Starter #1
Just ran my son to an appointment on the other side of Dayton from where we live. I knew I would be close to some public chargers so I did an experiment. I drove on the highway getting there but took surface streets on the way back. I have heard many in this forum talk about how the ED battery performs much better taking surface streets than it does on the highway. The reasons are pretty obvious but I had never really looked at how extreme the difference could be. The difference in battery consumption is pretty incredible. Here are my results.

Highway:
25 minutes
23 miles
50% battery used

Surface Streets:
35 minutes
18 miles
22% battery used

On the surface street portion, I even messed around and stopped to take a couple pictures and stuff.


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All cars experience exponentially increasing air resistance at higher speeds. I can confirm for you a similar trip. There @120km/h used 60% and back @75km/h used 20-25%. Roughly a 35km trip
 

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Having driven ICE cars all my life, I am atuned to the thought that stop-n-go traffic yields horrible mpg. And that getting up into 5th or 6th gear (depending on the transmission) is ideal for maximum highway mpg. Well, driving my 500e has taught me that for street and stop-n-go, you can't beat electric. But it also follows, that at freeway speeds, the EV range drops precipitously. It is so, because around here the 'unofficial' speed limit is 80mph, though the signs say 65mph. Welcome to the Silicon Valley! Putting it into cruise at 60mph might get you run over, but at least you are reducing the discharge rate.
 

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MY08 cabrio MY09 cabrio Brabus MY15 ED
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And are you still running the factory, OEM stagger or have you changed wheels/tires?
 

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Discussion Starter #7
And are you still running the factory, OEM stagger or have you changed wheels/tires?


Still running the original setup. I bought a new set of rims last years but I kept the original dimensions. Is there any thought that a different setup would yield better results?


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Both your experiences are pretty dramatic. The drag force - and therefore the energy expended for the trip varies as a square of the car's airspeed (did you note the wind direction on these trips?) The so-so CD of the smart ED (.35) probably hurts too.

The way an IC engine car can still get better fuel economy at steady 120 kph/75mph than stop-and-go driving just illustrated the appalling inefficiency of IC engine cars in this mode - only a couple percent of the gasoline's energy is getting turned into useful work in stop-and-go traffic. Compare this to probably about 85 percent with battery-electric drive.
 
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