Comment by potatolicious | Hacker News Reader

Comment by potatolicious | Hacker News Reader

Not really a surprise - I don't think there was really any doubt about the performance of the Tesla in normal weather. The NYC area right now is well above freezing, approaching +10C in the daytime, nowhere near the deep freeze that occurred during the NYT drive.

This still doesn't put to rest the expected (but somehow controversial) concerns about lithium battery performance in cold weather. This concern IMO needs to be put to rest if electrics want to break into the mainstream market. Early adopters may be willing to plan judiciously around range and expected weather, but I doubt mainstream consumers will be so forgiving.

Having a car of (somewhat) limited range lose a large chunk of its battery just sitting overnight in a parking lot, in weather that is cold but hardly unusual for the region, is a problem. That both on-board software and human advisers seem poorly prepared to compensate for this is hardly a nail in Tesla's coffin, but does need to be sorted out.

That whole debate is becoming utterly ridiculous. Either it works as Tesla Motors says, or it doesn't.

If it's so hard to get cold temperatures in the States, just send one unit up here a few miles North to Canada, we'll be back in the -20C during the week.

Alaska is a popular place for cold weather testing among many manufacturers. Subaru, in particular, beats the crap out of their cars for extended time periods in sub-zero temperatures.

Teslas are big sellers in Norway and Switzerland, yet (and I travel there often and even looked in Zurich showrooms) I don't hear them concerned.

Are they such big sellers that most of the buyers can't afford to treat them like toys?

Coincidentally also the two richest countries of Europe. I'm just guessing here, but there's a chance the percentage of buyers in those countries who don't also have a sizeable conventional car might be smaller than in other countries.

Electric cars are so common in Norway because they're actually cheaper there (lots of taxes on gasoline powered ones). At least that's what I heard.

In Switzerland you're almost certainly closes enough to a decent sized town to stop and get rescharged at any time. Europe in general is just not as spread out as the US, nor are its cities defined by freeways. Different world.

Tesla's other challenge, i suspect, will be really hot spread out places like parts of Australia.

If you drove the distance from Boston to DC in Switzerland, you wouldn't be in Switzerland anymore. The whole country fits inside New York State.

I was particularly thinking about the evils of cold nights

Random fact: Switzerland actually fits inside New York State 3.4225505632 times … :)

Switzerland is about the size of West Virginia.

And even slightly more rugged in terms of landscape.

Tesla sales numbers for Switzerland:

2010 = 44 / 2011 = 51

Source: http://www.auto-i-dat.ch/download/fahrzeugmarkt/Schweizer_Fa...

According to a media release from July 27, 2012, Tesla counted more than 130 Tesla cars in Switzerland:

http://www.presseportal.ch/de/pm/100020821/100722406/tesla-b...

Number of Teslas registered in Norway: 15 in 2010, 48 in 2011, so they sold 33 Teslas in 2011.

Source: Statistics Norway[1], the official state agency for everything statistics.

Compared to say ~300,000 registered Toyotas (2011), I guess it depends on how you define "big" :)

But we do have a somewhat sizeable enthusiast "electric car" community. We deal with the cold by plugging in whenever possible, and most electric cars are used only for local transport.

There's apparently two Tesla S in Norway at the moment. It has generated interest here as well, and we have articles like "How to charge the Tesla Model S" [2] on a site that translates to "charging-stations.no",

[1] http://statbank.ssb.no/statistikkbanken/Default_FR.asp?PXSid...

[2] http://www.ladestasjoner.no/nyheter/75-hvordan-kan-tesla-mod...

I thought one of the benefits of electric cars was that since you had them plugged in overnight you could program them to automatically heat the car to a pleasant temperature for when you went outside to drive, taking energy for this directly from the charger, rather than the battery. And that if your schedule was a bit more unpredictable you could activate this via a smartphone app as well.

Does the Tesla not do that (yet)?

It can and does, but the writer in the NYT did not do that. Wherever he stayed overnight probably didn't have a charger? Although I've never seen a building without a standard outlet somewhere outside... perhaps it wasn't available or he just thought he didn't need it.

Plugging in overnight would have made the NYT review a non-event. In fact, it doesn't look like the CNN review involved an overnight stop at all.

NB: Tesla claims you don't have to plug in overnight. Whatever other problems the NYT reviewer had, he wasn't cheating by leaving it unplugged overnight.

This probably works well when you're at home and have your own charging point in the garage. It doesn't work so well when you're in a hotel somewhere and the nearest charging point is a public one in the next town over. (Attempting 110V charging may actually make matters worse in cold weather, based on the experiences of other Tesla owners.)

Is it possible and would it help to warm the batteries ala glow plugs for diesel?

I believe it presently does. In fact, I believe that's the reason why the battery charge level dropped overnight in Musk's presentation of data and why, according to some folk, plugging it in to a normal power socket isn't enough to actually charge it as the battery pack draws more power than the socket can supply simply keeping the thing warm.

Such a process will of course drain the battery which still achieves the end result of 'can travel less distance on a full charge'.

Would better thermal insulation help? Or it is already best economically viable?

I've no idea, I'm no expert in the tech. I'm sure 'better' would always help (though not necessarily overnight when it's a case of just slowing equalisation since you're talking long timeframes) but I don't know if there is a both better and economically viable process?

I'm sitting in front of a 1500 watt radiant heater, it seems implausible that 1500 watts isn't enough power to keep a car sized battery pack in an enclosed space warmed to operating temperature.

For an idea what 1500 watts will do, I keep a 400 square foot room with only an R8 (US) ceiling and unheated space below at a 20°F differential to outside with this heater. It can't keep up when it gets too cold out, but my room has about 200 times the surface area of a Tesla battery pack.

Edit: maybe more than 20°F. I just shut it off for the day at °85F inside and 37°F out, so 48°F difference, but it is sunny, so the roof and two walls are warmer than 37°F. Data collection is hard. If only I worked in a uniform spherical room located in empty space…

Of course, for every hour of operation of the heater, you're using up about 1.5% of the battery capacity.

I'm rather thinking of being plugged in. 1500 watts is about all you can plan on drawing without blowing a breaker. The context, if I understood correctly, was that plugging in to a 120v household outlet was a net loss because 1500 watts was insufficient to warm the batteries to charging temperature and that presumably some numbskull in Tesla's software group decided to run the heaters even if it resulted in a net loss of power.

The explanation of the anecdotes is probably complicated, but I believe that the Tesla chargers monitor the voltage at the input to the car and reduce their current draw to keep a minimum voltage. So if your 120v transformer is a little on the low side (they vary) and maybe you used that 100' 16g extension cord you had handy, and maybe your house was wired when aluminum house wiring seemed like a good idea and that outlet has a bit more resistance between the wire and the terminal screw, you might be getting a lot less than 1500 watts. There could well be a point in the charging curves where there is a problem, but I don't think it is because 1500 watts isn't enough.

If you're plugged in, just charge the battery.

I think the number I heard for heating the battery was 1.3kW. The model S battery is long and flat and hence has lots of exposed surface to lose heat. Also, it was in the teens when the original reporter left his car outside. So, is plausable.

Diesel also needs special considerations in colder weather (the fuel becomes too viscous at lower temperatures). Just a different set of problems to petrol, not a dealbreaker imo.

As someone who had an 80's diesel car as his first, I can verify that even leaving them in a high school parking lot during a cold winter school day in Maine is a bad idea.

I had to wait about a week for the weather to warm up before the glow-plugs were enough to start it.

However, I believe a Tesla is a different case. I always keep my car's fuel tank above half-filled to preserve the fuel filter (and you should too). While the Tesla might lose some charge during the day in a parking lot or overnight, I can't imagine it would be a seriously substantial amount.

How does keeping the tank fuller preserve the filter? All the crap in there sinks to the bottom anyway, no?

I think he meant the fuel pump. It can overheat if fuel levels get too low.

Correct, I mis-typed. Also, the more room there is in the tank, the more room there is for water vapor in the air filling the rest of the tank to collect. This can cause rust.

Not really, any more. The fuel is winterized at point of purchase, so fuel geling is rather unlikely these days (and if it does, there are additives that will un-gel it.

Modern glow plugs are also much better. In my VW TDI, at 10F the glow plug cycle is only about 3 seconds, and then it fires right up. No glow plugs need at all above 35F.

Same for our 2011 TDI. Never had to worry about fuel or engine issues, even in quite cold weather (not arctic, but we live in RI, so there are some cold winter nights to contend with).

Regarding the fuel, there are some details, along with some discussions of operating temperature, in the Wikipedia page: http://en.wikipedia.org/wiki/Winter_diesel_fuel. The temperature ranges suggest that you're unlikely to have serious issues with your diesel car, if you buy fuel appropriate for the season. The inconvenience factor of owning a diesel car compared to a petrol one is pretty minimal, as far as the sort of cold weather that most people who might consider buying a car (as opposed to something with tracks, skis, or 4' tyres) will generally encounter.

Usually you're right. Unfortunately we had a bit of a facepalm last year here in MN when the diesel-powered school buses wouldn't start at -10F or something. It turns out that in the state's hurry to push biodiesel on municipal vehicles, someone forgot that it gels at higher temperatures than "normal" diesel.

Thousands of schoolchildren were quite happy, though.

We had most of december and january below -15C sometimes down to -30C and diesel cars had no problems. Most problems were caused by guess what: batteries not giving enough juice to start. Diesel cars, having bigger batteries, were actually more reliable.

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