
Running Out of Power in a Tesla on the Side of a Highway - yiransheng
http://www.theatlanticcities.com/technology/2014/04/what-running-out-power-tesla-side-highway-taught-me-about-road-trip-tomorrow/8978/
======
sologoub
From the article: "We're just about fully charged, and the car estimates it
can travel 247 miles before we need more juice."

And then "The estimated 265-mile range of a fully equipped Tesla Model S has
allayed some concerns about having enough juice to get where you want to go."

So they left on a long trip with a 93% charge knowing that it was going to be
close and fell short by 3 miles... why is this news or article worthy?

I don't own a Tesla and don't plan on owning one any time soon, but articles
like this really annoy me, as they don't provide any meaningful substance. The
estimated ranges for gas cars are affected in the same way by driving
conditions and the driver.

The person they refer to who did a CA to VA trip seems to have a much more
pragmatic approach to this and as the result has a mostly uneventful trip. His
good experience has nothing to do with being a Tesla fanatic. He's just
charging the car all the way and makes sure the distance he needs to go is
reasonably doable.

~~~
rogerbinns
What I don't understand is why the car didn't use route information in range
estimates (assuming they entered their destination). It would have known about
elevation changes. If getting map information from Navteq then it could also
know about average speeds and historical traffic patterns.

It could also have given more driving guidance. I didn't see how they came up
with 63mph, but the car itself should know about energy-speed tradeoffs could
have told them a more appropriate speed to go.

And if knowing they wouldn't reach a charger it could have had them stop
closer to somewhere that could help, or direct the AAA equivalent to them for
the moment they ran out.

People keep mentioning the mental effort of electric cars for these issues,
but the car itself can address those and do so far more effectively.

~~~
XorNot
Even if you did all this, you can't predict everything in advance especially
on a long trip.

Trying to drive anywhere cutting it this close, in any car, is likely to leave
you stranded.

~~~
rogerbinns
They started out with a ~15% margin. How close is acceptable?

Behind the scenes the mileage estimates are really a central number with error
bars. In this case the electronics could definitely have come up with better
numbers based on altitude changes. And it definitely could have given guidance
on speeds to maintain whatever margin is comfortable.

------
NDizzle
As someone who has made that same drive - from Barstow to Kingman, I can't
imagine attempting that stretch in an electric vehicle.

There's a neat part of the trip on the reverse route, when you're coming down
the mountains and into CA. You can basically mark (in your head) a landmark
across this enormous valley in your head. And then you drive towards it,
cruise control at 85, (unless you're in a Tesla!) for roughly the next hour
until you reach that spot.

You can just see so far and there is absolutely nothing. Except for that
little oasis travel center / truck stop in that valley, which is almost
exactly the halfway point between the two cities.

I bet they'll have a supercharger station there sometime soon.

------
coin
"In any effort to save battery life, we turn off the stereo and dim the huge
touch screen control panel." The radio and lights use order of mangnitudes
less than the drivetrain. This reminds me of all the people that unplug their
TV when not at home, afraid of the standby electricity usage.

~~~
Kylekramer
Given that every bit of energy gets the driver closer to their destination,
your comparison seems a bit unfair. Sure, it may be a small difference in the
big picture, but that small difference could be the difference between making
it and having to call a tow.

~~~
jws
A backlight is something like 3 watts, a car stereo is consuming something
like 10 watts. Running them for an hour is 13 watt hours.

A model S uses 237.3 watt hours per kilometer.

If you turn them completely off for an hour, you can go an extra 50 meters.

~~~
Kylekramer
And 50 meters can be the difference between a tow and making it, which is my
point. Yes, I am aware it is a small amount. But given the drastically
different experiences between "make the charger" and "not make the charger", I
would hardly compare it to a person saving fractions of a penny by unplugging
electronics when they leave the house.

~~~
Brashman
50 meters is the difference between making it and having to push the car to
make it. It'd make for a funny story, but you're not going to be kicking
yourself for leaving the display on.

~~~
zaroth
Perhaps the willingness of the software to allow the battery to bleed itself
out should increase as you close in within a few miles of a super-charger.

------
dkhenry
So my first instinct when I saw this was to immediatly classify this guy as a
tesla detractor just trying to get some publicity by bashing the EV. However
its a well written piece, I imagine we have all been in a similar situation
with gas cars and there is nothing in particular about this that is negative,
he never blames tesla and describes how after this instance of being stranded
he was able to complete the return trip successfully. I think it paints a good
picture of how I expect I will be once I get my first EV, I will probably run
out of juice on a long trip at least once or twice ( I have come pretty close
in conventional cars ) and its good to know that there are still some things I
might not have thought about ( the towing situation in particular )

------
ams6110
I didn't realize that so many towing/roadside assistance companies won't help
you if you're in an exotic/expensive car. Another interesting factor to weigh
into the idea of owning a Tesla, at least for now.

~~~
toufka
The flip side is that if you're in an exotic/expensive car people will pay for
you to get help. The rental car companies will help you, the dealers will help
you, and when you find someone finally willing to take their money, they'll
help you gladly and kindly for that nice payday they're getting.

------
001sky
What about useing technology to solve this problem? Right now if you run out
of petrol, they send a tow-truck or a flat-bed with a 5 galon tank of gas. Why
not have some sort of truck-with-a-battery than can provide ~30miles (10%ish)
recharge.

It's a legitimate issue that you may take a detour--forced or by erroneous
navigation--and so you might end up a bit short for whatever reason (that's
not an issue specivic to ev/tesla). And it seems unrealistic to call the
driver (any driver) 'stupid' 'ignorant' 'not worth of the car' ... which are
basically lazy ad-hominem attacks. The issues is well understood by peole of
experience in actual long-distance navigation.

~~~
giulianob
I was thinking the same. Why can't you hook it up to a running car and get
some charge in the battery to get to the nearest charging station?

~~~
bri3d
Terrible back-of-the-envelope math disregarding any kind of loss or
inefficiency, and assuming a magical DC->DC power system which would convert a
car's 14.4V alternator source to something suitable to charge a Tesla without
losing anything:

A "normal" modern car's alternator can put out ~100 amps at 14.4VDC. That's a
maximum of about 1.5kW, which will charge a Tesla at a rate of about 2 miles
of driving per hour of charging, again assuming a magical efficiency.

The reality is that the car's own systems take at least a few hundred watts
and alternators aren't built to run at maximum load all the time and are
likely to fail after a while running near capacity. Plus, the Tesla doesn't,
to the best of my knowledge, contain any sort of DC->DC hardware capable of
bringing 14.4V up to the necessary charge voltage, and even if it did losses
would be at least on the order of tenths.

So, even with a good, running car and a theoretical alternator, you'd be
waiting a _very_ long time next to the running car (and burning a lot of gas)
before your Tesla would go anywhere.

Obviously it would be possible to build, for example, a tow truck with much
greater charging capacity and as time goes on we'll probably see at least a
few of those in real life. But the fact remains that gasoline provides an
excellent energy density in a convenient liquid form and that for certain edge
cases, its conveniences will be hard to beat.

~~~
001sky
Come to think about it--the easiest hack-- is just a piggback battery. Lets
say the Tesla power-source is 500 pounds. 1/10th would be 50 pounds. Assuming
replacement of the battery is $15K at cost, that would be a $1500 asset. 4x of
them would add ~$6K per charging depot (<~5% of planned capital outlay).
Transport to site by 3rd pary service using a pickup truck (ie, no fancy gear
needed).

Volumne would be the size of a a carry-on wheelie bag. The engineering
solution would be to have a second charging point internal to the
passenger/trunk--perhaps in the 2.0 version of the Tesla models currently on
the board. The only engineering consideration would be that the li-ion
powertrain would need to operate during charge (like a laptop or cell phone)
but would presumably overcome.

~~~
bri3d
That's an interesting idea, although I think it'd be hard to make a piggyback
battery pack light enough. The Tesla's swappable battery pack module including
frame/supports, armor, and coolant weighs over 1,300lb.

Nobody wants lithium batteries in their passenger compartment, but I do
suspect it might be possible to make a ~200lb pack that would fit in a Tesla's
frunk and move it at least a few miles. Thermal management would be a
tremendous challenge in that area unless the "auxiliary battery" port could
somehow interface safely with the car's existing liquid cooling system.

------
devindotcom
I hadn't realized the cost of the superchargers stations was more or less
known. If I'm honest, even the high-end estimate ($175,000) seems like a
bargain for a largely self-sustaining station that's a major selling point for
your vehicle platform. They may even get little communities around them,
coffee shacks and the like. I would have guessed they cost half a million
each, personally.

~~~
higherpurpose
That's why hydrogen cars can't compete with electric cars. Even at $100,000
per charger, electric car infrastructure is still appearing pretty slowly. Now
imagine how much it's going to take when a hydrogen charging station is more
like $1.5 million - but for some reason the states want to fund _those_
instead of electric chargers. It makes no sense.

Not to mention that with such chargers you can charge you car for _free_ ,
while hydrogen will still cost quite a bit (probably not much less than gas).

~~~
magic_haze
1\. You won't have to wait for an hour for your tank to fill up. 2\. The
supercharges aren't free: you're paying for them when you buy the car. And
it's proprietary: you can't use it with other electric cars.

------
theatraine
I'm surprised that the author didn't mention or try to draft. As Mythbusters
showed, drafting can save quite a bit of fuel, might have been a better idea
than trying to pass the trucks.

"drafting behind an 18-wheeler truck was tested and results showed that
traveling 100 feet (30 m) behind the truck increased overall mpg efficiency by
11%. Traveling 10 feet (3.0 m) behind the truck produced a 39% gain in
efficiency"

[http://en.wikipedia.org/wiki/Drafting_%28racing%29](http://en.wikipedia.org/wiki/Drafting_%28racing%29)

~~~
rbobby
And is very dangerous. People always forget the dangerous part.

~~~
bennyg
Exactly. A tap of the brakes at 70mph means a fraction of a second to match or
best that at 10 feet distance. You're gonna' die if you try that.

~~~
omegaworks
This looks like a nice use case for partial robot control.

~~~
anko
like volvo? [http://www.sartre-
project.eu/en/Sidor/default.aspx](http://www.sartre-
project.eu/en/Sidor/default.aspx)

------
jacquesm
The bigger problem is that an electric car can not take along a 'spare gas
cannister' to get you to the nearest gas station.

As charging stations become more common this will be less of a problem but
somehow I can't envision the future equivalent of a gas station that processes
a few hundred cars per hour when doing the same thing electrically with
everybody waiting for much longer times. Also, a few hundred cars concurrently
recharging their batteries will require significant power infrastructure, gas
stations can be put up just about anywhere where roads go (and that's not
always where the power lines are), in a pinch you can power a whole gas
station off a small genset.

I'm sure smarter people that me have thought this through :)

Would a gas car running out of fuel get similar coverage?

Range anxiety at the time that gas stations were few and far between would
have been a comparable item.

~~~
userbinator
> The bigger problem is that an electric car can not take along a 'spare gas
> cannister' to get you to the nearest gas station.

I think if electric cars become more common and commoditised, mostly
standardised things, extra battery packs will become popular.

~~~
jacquesm
Storing large numbers of battery packs safely would be a challenge, and they
still would need to be recharged.

A single 50K liter fuel drop is the equivalent of 1.75 TJ, that's 486111 KWh
(one liter of gasoline is 35 MJ). If a typical car has a 60 liter gas tank
that's 850 cars give or take. A busy gas station will go through that in a few
hours. Say 200 cars / hour, that's a bit over 4 hours. So the electrical
equivalent of that 50K liter fuel drop delivered over the space of 4 hours
(assuming equal efficiency, which probably is not correct) would require 125
MW of electrical input. As a check: One Tesla super charger is about 100 KW,
running 200 of them in parallel would require 20 MW.

So it appears that even at roughly 5 times the efficiency of a gasoline engine
the power requirements of a filling station capable with such volumes would be
quite significant. You're talking high voltage distribution to the stations at
a minimum to reduce the losses, even at 10KV that's still 2K amps.

Pretty sleepy here so apologies ahead of time if I messed up too much on the
calculations.

------
jfoster
"He foresees a greater variety of hybridizations combining oil, natural gas,
electric batteries, hydrogen fuel cells and maybe some as yet undeveloped
alternative fuel options."

Surely engines that combine multiple energy sources are more expensive and
less efficient than engines that use a single source? My understanding of the
current hybrids is that they exist because one energy source (petrol) can be
quickly and easily replaced, whereas the other (electric battery) takes time
to replace and isn't as easily available. Best I can tell, that makes hybrids
a temporary solution to the lack of widely available better energy sources.
Once most cars have settled on a non-petrol energy source, I can't see why
hybrids would continue to exist.

------
viraptor
I was trying to do some searches on google maps to figure out whether they
were specifically aiming for supercharger stations, or are there really no
electric chargers on the way. With the cities by the end of the route and
standard gas stations on the way, I was hoping to see some "electric char
chargers" or similar point. Are they really missing, or am I looking for the
wrong thing?

I'm used to seeing them in almost every mall / bigger parking these days so it
looks unlikely they're missing completely. Basically I'm trying to decide if
this article is simply anti-tesla (they seem to really concentrate on
superchargers only), or is it describing poor availability of charging points
in general.

~~~
jurassic
I don't know for sure that there are no other places to charge, but there's
not much in the Mojave desert so it would not surprise me. It's easy for me to
imagine no chargers between Barstow and Kingman, because there is basically no
civilization out there between cities. I haven't driven the AZ segments, but
Mojave towns like Ludlow are basically a single gas station, a single diner,
maybe a church and nothing else. If I thought I wasn't going to make Kingman I
might have turned toward Havasu City, but it's only ~20 miles closer.

~~~
waterlesscloud
Needles is good pit-stop town, but if Tesla put a station in Kingman (to catch
Vegas bound traffic, no doubt) then it might take a while to fill in Needles.

------
tokenadult
"The seemingly random parking lots I'm traveling between are sites of a new
nationwide network of fast battery charging stations for drivers of Tesla's
Model S." If I am reading the article correctly, the journalist driver is
trying out a trip between Supercharger stations, for which the mileage
estimates on a Tesla as shipped from the factory would be quite relevant.

The article has a good discussion of the trade-offs between having a lot of
charging stations and not having so many at the beginning of the electric car
era. This paragraph especially caught my eye:

"Tesla won't offer any details about how much it costs to build and operate
these Supercharger stations, but according to internal documents obtained by
TechCrunch, they're an expensive effort, marketing or no. Each Supercharger
station is estimated to cost between $100,000 and $175,000, and Tesla is
picking up the entire tab — from installation to maintenance to the cost of
providing the large amount of energy needed to charge their cars so quickly.
Nicholas says Tesla is internalizing this cost and adding it into the price of
the Model S, which can range from about $70,000 to more than $100,000."

~~~
zaroth
Read the Better Place expose posted recently for more on this kind of
approach. Here's hoping it works out better for Tesla.

------
foobarian
Can the Tesla charge off a regular 120V outlet? If so I'd probably carry
around a gas generator for insurance. Might take a while but it could probably
charge up enough range to get to a supercharger. Bonus points for the
wonderful gasoline smell in the cabin.

~~~
tlb
Yes. You gain 2.5 miles/hr charging from 120V 15A, or 25 miles/hr charging
from 240V 50A.

------
tzs
In my normal car, if I run out of gas and get stranded, I can at least listen
to the radio for several hours while I wait for help. Do electric cars reserve
any power for the radio when they run out of drive power?

------
etep
Should be running out of energy.

------
mattkrea
I hope the Tesla team write another blog article blasting this story.

It is unbelievable that this is expected to be newsworthy.

~~~
mattkrea
At least please provide some explanation for a downvote. Did I not give enough
reason behind my feelings?

~~~
jpatokal
I didn't downvote you, but the article is not some obvious hit job. As a
potential future Tesla owner living in a country with a whole lot of empty
space (Australia), I found it quite interesting and surprising that getting
the Tesla towed even a short distance would be such a problem.

