Roadster Efficiency and Range

[dpeilow]

Tesla Motors - touch

JB's answer to JC?

 

[graham]

This is a great blog entry!

While this graph shows that driving range greater than 300 miles should be possible, the conditions to do this are quite rare: steady-state driving at 30 mph (no stops or starts) for more than 10 hours! What is most relevant for real world driving and trip planning is how the range varies between perhaps 45 mph and 80 mph.

One clear driving “tip” to take away from this is if you are ever nervous about making it to a given destination: you will do much better to slow down instead of speeding up. I’ve talked with many people who intuitively think that minimizing time to the destination will also minimize the energy usage, but just the opposite it true!

And this was not a direct response to JC (Carmack or Clarkson :smile but some other tests being done by some owners.

This graph seems to suggest that at 65 mph, you will get about 200 miles, which is quite a good range.

I hope they continue with the blog content. This one was a great one.

 

[vfx]

JB wrote

"So it is good to make sure that you are not “accidentally” carrying extra weight in the trunk or elsewhere..."

So when you are out on the town in your Tesla Roadster, you better skip that dessert!

 

[dpeilow]

So it would be possible to to drive to Scotland on one charge in 23 hours, not 3 days! :biggrin:

 

[Tdave]

So 400 mile range is possible ... theoretically.

Now I want to see someone do a real world trial to see just what's possible.

 

[vfx]

So it would be possible to to drive to Scotland on one charge in 23 hours, not 3 days! :biggrin:

How long in a Prius?

 

[Tdave]

So, Mr. Clarkson, I don't see 55 miles on that chart.

 

[dpeilow]

How long in a Prius?

Probably 7 to 8 hours.

So, Mr. Clarkson, I don't see 55 miles on that chart.

Funny - that's exactly what I've said on the company blog (currently awaiting moderation). :smile:

 

[Tdave]

Funny - that's exactly what I've said on the company blog (currently awaiting moderation). :smile:

I know. I plagiarized you. Hope you don't mind. It was a great line.

 

[dpeilow]

No worries - Clarkson deserves to hear that as many times as possible :smile:

 

[Tdave]

This also tells us if you are trying to limp back home on a nearly dead battery, keeping it at 15-20 mph is your best strategy.

 

[malcolm]

Excellent information.

You can expect about a +/- 10Wh/mile variation with a +/- 20% variation in tire pressure

You have to pick the right time of day to get away with 15-20mph driving, though.

 

[doug]

I though it would be interesting to see how long you could drive (in hours) versus speed:

 

[shark2k]

Interesting Doug. If you need* to drive at 65 mph constantly, you would only get about 3 hours worth of driving according to your chart. Electric cars definitely benefit from more city driving over highway driving.

*need meaning you are on a highway where the speed limit is 65 mph :biggrin:

-Shark2k

 

[Tdave]

Electric cars definitely benefit from more city driving over highway driving.

Well, keep in mind that those charts assume maintaining a constant speed, not the stops and starts you get in real city driving.

 

[doug]

Back when this forum started, someone was particularly interested in electric car racing and spent a lot of time trying to calculate how long a Roadster my last in a race. I'm pretty sure he started with some constant speed calculations. Anyone (TEG) remember who that was?

 

[shark2k]

Well, keep in mind that those charts assume maintaining a constant speed, not the stops and starts you get in real city driving.

Yeah, I know. But still. Highway driving has minimal (if any depending on conditions) reason to use the brakes. The city driving gives more opportunity to use the regen. These charts just help confirm that.

-Shark2k

 

[WarpedOne]

Well, keep in mind that those charts assume maintaining a constant speed, not the stops and starts you get in real city driving.

Sure, but city driving is a great opportunity to take advantage of regen. Unfortunately, Roadster's regen braking really is only first gen tech. No adaptation, only rear wheels. All braking in cities should be done via regen, except emergency braking of course.

If you are in stop'n' go traffic where you accelerate up to 30 mph and then brake to full stop again and you do that 100 times, with 80% drivetrain efficiency you recoup about 5kWh of energy.
How much you spent depends on how far you have driven.

 

[doug]

Here's an old thread about range:
http://www.teslamotorsclub.com/tesla-roadster/76-range-speculation.html
We used to do a lot more math on this forum.

 

[malcolm]

One way to dirve slowly would be to deliberately place yourself behind a caravan or RV in holiday traffic. They get blamed for the slow speed; you get the good range.

However, you'd probably need some sort of relaxation music on the stereo.