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Perils of the long range electric car

You’ve probably seen the battle going on between Elon Musk of Tesla and the New York Times over the strongly negative review the NYT made of a long road trip in a Model S. The reviewer ran out of charge and had a very rough trip with lots of range anxiety. The data logs published by Tesla show he made a number of mistakes, didn’t follow some instructions on speed and heat and could have pulled off the road trip if he had done it right.

Both sides are right, though. Tesla has made it possible to do the road trip in the Model S, but they haven’t made it easy. It’s possible to screw it up, and instructions to go slow and keep the heater low are not ones people want to take. 40 minute supercharges are still pretty long, they are not good for the battery and it’s hard to believe that they scale since they take so long. While Better Place’s battery swap provides a tolerable 5 minute swap, it also presents scaling issues — you don’t want to show up at a station that does 5 minute swaps and be 6th in line.

The Tesla Model S is an amazing car, hugely fun to drive and zippy, cool on the inside and high tech. Driving around a large metro area can be done without range anxiety, which is great. I would love to have one — I just love $85K more. But a long road trip, particularly on a cold day? There are better choices. (And in the Robocar world when you can get cars delivered, you will get the right car for your trip delivered.)

Electric cars have a number of worthwhile advantages, and as battery technologies improve they will come into their own. But let’s consider the economics of a long range electric. The Tesla Model S comes in 3 levels, and there is a $20,000 difference between the 40khw 160 mile version and the 85kwh 300 mile version. It’s a $35K difference if you want the performance package.

The unspoken secret of electric cars is that while you can get the electricity for the model S for just 3 cents/mile at national grid average prices (compared to 12 cents/mile for gasoline in a 30mpg car and 7 cents/mile in a 50mpg hybrid) this is not the full story. You also pay, as you can see, a lot for the battery. There are conflicting reports on how long a battery pack will last you (and that in turn varies on how you use and abuse it.) If we take the battery lifetime at 150,000 miles — which is more than most give it — you can see that the extra 45kwh add-on in the Tesla for $20K is costing about 13 cents/mile. The whole battery pack in the 85kwh Telsa, at $42K estimated, is costing a whopping 28 cents/mile for depreciation.

Here’s a yikes. At a 5% interest rate, you’re paying $2,100 a year in interest on the $42,000 Tesla S 85kwh battery pack. If you go the national average 12,000 miles/year that’s 17.5 cents/mile just for interest on the battery. Not counting vehicle or battery life. Add interest, depreciation and electricity and it’s just under 40 cents/mile — similar to a 10mpg Hummer H2. (I bet most Tesla Model S owners do more than that average 12K miles/year, which improves this.)

In other words, the cost of the battery dwarfs the cost of the electricity, and sadly it also dwarfs the cost of gasoline in most cars. With an electric car, you are effectively paying most of your fuel costs up front. You may also be adding home charging station costs. This helps us learn how much cheaper we must make the battery.

It’s a bit easier in the Nissan LEAF, whose 24kwh battery pack is estimated to cost about $15,000. Here if it lasts 150K miles we have 10 cents/mile plus the electricity, for a total cost of 13 cents/mile which competes with gasoline cars, though adding interest it’s 19 cents/mile — which does not compete. As a plus, the electric car is simpler and should need less maintenance. (Of course with as much as $10,000 in tax credits, that battery pack can be a reasonable purchase, at taxpayer expense.) A typical gasoline car spends about 5 cents/mile on non-tire maintenance.

This math changes a lot with the actual battery life, and many people are estimating that battery lives will be worse than 150K miles and others are estimating more. The larger your battery pack and the less often you fully use it, the longer it lasts. The average car doesn’t last a lot more than 150k miles, at least outside of California.

The problem with range anxiety becomes more clear. The 85kwh Tesla lets you do your daily driving around your city with no range anxiety. That’s great. But to get that you buy a huge battery pack. But you only use that extra range rarely, though you spend a lot to get it. Most trips can actually be handled by the 70 mile range Leaf, though with some anxiety. You only need all that extra battery for those occasional longer trips. You spend a lot of extra money just to use the range from time to time.  read more »

Your session has expired. Forgot your password? Click Here!

We see it all the time. We log in to a web site but after not doing anything on the site for a while — sometimes as little as 10 minutes — the site reports “your session has timed out, please log in again.”

And you get the login screen. Which offers, along with the ability to log in, a link marked “Forget your password?” which offers the ability to reset (OK) or recover (very bad) your password via your E-mail account.

The same E-mail account you are almost surely logged into in another tab or another window on your desktop. The same e-mail account that lets you go a very long time idle before needing authentication again — perhaps even forever.

So if you’ve left your desktop and some villain has come to your computer and wants to get into that site that oh-so-wisely logged you out, all they need to is click to recover the password, go into the E-mail to learn it, delete that E-mail and log in again.

Well, that’s if you don’t, as many people do, have your browser remember passwords, and thus they can log-in again without any trouble.

It’s a little better if the site does only password reset rather than password recovery. In that case, they have to change your password, and you will at least detect they did that, because you can’t log in any more and have to do a password reset. That is if you don’t just think, “Damn, I must have forgotten that password. Oh well, I will reset it now.”

In other words, a lot of user inconvenience for no security, except among the most paranoid who also have their E-mail auth time out just as quickly, which is nobody. Those who have their whole computer lock with the screen saver are a bit better off, as everything is locked out, as long as they also use whole disk encryption to stop an attacker from reading stuff off the disk.  read more »

Mesh networking when the cell network fails

Interesting article about a new plan for mesh networking Android phones if the cell network fails. I point this out because of another blog post of mine from 2005 on a related proposal from Klein Gilhousen that he was pushing after Katrina.

The wifi mesh has the problem that wifi range is not going to get much better then 30-40m, and so you need a very serious density of phones to get a real mesh going, especially to route IP as this plan wishes to. Klein’s plan was to have the phones mesh over the wireless bands that were going unusued when the cell networks were dead (or absent in the wilderness.) The problem with his plan was that phone tranceivers tend to not be able to transmit and receive on the same bands, they need a cell tower. He proposed new generations of phones be modified to allow that.

But it hasn’t happened, in spite of being an obviously valuable thing in disasters. Sure there are some interference issues at the edges of legitimate cell nets, but they could be worked out. Cell phones are almost exclusively sold via carriers in the many countries, including the USA. They haven’t felt it a priority to push for phones that can work without carriers.

I suspect trying to route voice or full IP is also a mistake, especially for a Katrina like situation. There the older network technologies of the world, designed for very intermittent connectivity, make some sense. A network designed to send short text messages, a “short message service” if you will, using mesh principles combined with store and forward could make sure texts got to and from a lot of places. You might throw in small photos so trapped people could do things like send photos of wounds to doctors.

Today’s phones have huge amounts of memory. Phones with gigabytes of flash could store tens to hundreds of millions of passing (compressed and encrypted) texts until work got out that a text had been delivered. Texts could hop during brief connections, and airplanes, blimps and drones could fly overhead doing brief data syncs with people on the ground. (You would not send every text to every phone, but every phone would know how many hops it has been recently from the outside, and you could send always upstream.) A combination of cell protocols when far and wifi when close (or to those airplanes) could get decent volumes of data moving.

Phones would know if they were on their own batteries, or plugged into a car or other power source, and the ones with power would advertise they can route long term. It would not be perfect but it would be much better than what we have now.

But the real lament is that, as fast as the pace of change is in some fields of mobile, here we are 7.5 years after Katrina, having seen several other disasters that wiped out cell nets, and nothing much has changed.