Impact of cold on range, performance, battery life?

[AnOutsider]

Every time you stay at a hotel with your Model S, call and ask to speak with parking or someone in engineering. Explain to them you have an electric car and will be arriving on a certain date. Ask if they can find at least a 110V outlet or maybe even install a NEMA 14-50 outlet in the garage. While you are there, try and meet with management and ask for dedicated charge stations. This will go a long way into easing people's concerns about travel and make buying the Model S a little easier. This will all take many years of course.

Yeah, but it's going to take a certain type of early adopter to do this. "Normal people" aren't really going to want to put in that kind of work. If Tesla rolls out their SCs where that original map showed, most people should be fine though. I'm also seeing a lot of garages in Manhattan putting in outlets, so now when I go into NY for a meeting, I can select one close by and plug in there while I cab or walk around the city as usual. Downside is they aren't always high power, but it's better than nothing.

I would be willing to bet a dollar or two that your return trip was headed more toward the north or west then your trip there. Those 25 to 30 mph winds we had last Sunday night were brutal and have a huge impact on range.

Yeah, almost due west exactly. We hopped on 78 in NJ around exit 17 then headed west to exit 29 in PA. That big hill by the stroudsburg exit was a bit nerve wracking (crosswinds seem to ALWAYS be big there). I didn't even consider the winds as a factor though, figured the cold and heat were the biggest offenders.

 

[donauker]

Yeah, almost due west exactly. We hopped on 78 in NJ around exit 17 then headed west to exit 29 in PA. That big hill by the stroudsburg exit was a bit nerve wracking (crosswinds seem to ALWAYS be big there). I didn't even consider the winds as a factor though, figured the cold and heat were the biggest offenders.

The impact of running heat is pretty minor compared to that kind of wind. Lots of open stretches of headwind on that route that night. Put 25 mph of wind on the nose and the car will draw power like it is doing 90 when you are only driving 65.

 

[AnOutsider]

The impact of running heat is pretty minor compared to that kind of wind. Lots of open stretches of headwind on that route that night. Put 25 mph of wind on the nose and the car will think it is doing 90 when you are only driving 65.

That's actually pretty eye-opening, and sort of reinforces the points above. The masses won't want to calculate how many miles they need to go, check the temperature now and up to the time of their return trip and headwinds in both directions before leaving the house for a longer than usual trip. In that case, they'd probably take a gasser if they didn't have the ability to charge up at their destination -- and if they've got a gasser backup, they're probably in a smaller segment than Tesla hopes to eventually reach.

 

[NigelM]

How often does it hit 21 degrees in Florida? :wink:

Point taken, although we pretty much have the AC permanently on. OTOH, we have almost zero elevation changes. Still over 7,000mi we have averaged 340Wh/mi (see pic) and yes, it is 85F this afternoon.

(Guess it's time to carve this discussion into a new thread...)

 

[AnOutsider]

Point taken, although we pretty much have the AC permanently on. OTOH, we have almost zero elevation changes. Still over 7,000mi we have averaged 340Wh/mi (see pic) and yes, it is 85F this afternoon.

View attachment 16988

(Guess it's time to carve this discussion into a new thread...)

I hate you. I'm hoping to see those averages once it warms up here. Shouldn't it take a bit less to cool vs heat? I agree on split, perhaps "performance in various temperatures", but I think we have a thread on that too.

 

[brianman]

I hate you. I'm hoping to see those averages once it warms up here. Shouldn't it take a bit less to cool vs heat? I agree on split, perhaps "performance in various temperatures", but I think we have a thread on that too.

Don't hate the driver, hate the terrain and the weather, AO.

My lifetime average is 415 (it's improved from 426 with the weather change!) after 3485 miles, so I know where you're coming from.

 

[Norbert]

That's actually pretty eye-opening, and sort of reinforces the points above. The masses won't want to calculate how many miles they need to go, check the temperature now and up to the time of their return trip and headwinds in both directions before leaving the house for a longer than usual trip. In that case, they'd probably take a gasser if they didn't have the ability to charge up at their destination -- and if they've got a gasser backup, they're probably in a smaller segment than Tesla hopes to eventually reach.

How much calculation you need depends on how close to the max range you want to take it. So you got to balance that against how much effort you want to invest. But you can do a lot without calculation, and a good bit more with a little experience and/or calculation, and it will get better with more infrastructure. There is a lot of variety in the "masses", such that it isn't necessary to limit the target audience to a small niche.

 

[stopcrazypp]

I thought so too. Started with 269 on the dash, and figured I could use only 130 of range one way and be OK. I used 130, the temperature dropped below freezing while the car sat outside, and used more than 135 on the way back. 110v probably would have helped too, but again, what if there wasn't one at our destination? Being able to charge at my destination is not a common thing, which brings me back to having to stop to charge (or take a gasser).

In your specific case (okay one way and conditions change on way back) I imagine a look at the energy screen and adjusting your speeds lower accordingly would have still got you to your destination.

Although in the cold weather it's hard to tell how much range will be lost to battery heating (esp. if cold soak happens). So definitely there is a need to plug in at the destination assuming staying there for a significant period of time.

 

[dpeilow]

Rain is another one to add to the mix. All other things being equal it saps range causing more drag on the tyres.

I find this discussion interesting, because Roadster owners said that supercharging would remove the last barrier to EV adoption (well, that and high price), but now it seems Model S owners are finding other reasons for the mass adoption to be postponed.

The weather-related uncertainty is a biggy and 50% of the reason I drive what I drive. I've experienced battling 550Wh/mile and it's not nice.

 

[jerry33]

I find this discussion interesting, because Roadster owners said that supercharging would remove the last barrier to EV adoption (well, that and high price), but now it seems Model S owners are finding other reasons for the mass adoption to be postponed.

Well, there are only two areas of the country with any Supercharging so the barriers are still there for the majority of folks. Fact is, that until there are enough Model S out there with owner proving that electric cars are better there won't be any mass adoption. Think about how it worked for the Prius:

1. The Prius was sold in Japan only for three years.

2. A limited number were shipped to North America. In the first three years about 53,000 were sold. That's a lower production number than the Model S.

3. In 2004 the redesigned Prius was sold.

4. By 2009 there were one million sold.

5. In 2010 a new redesign was done.

6. In 2012 the Prius was the third largest selling car model (behind Corolla and Focus).

In Tesla terms, we can thing of point #1 as the Roadster. Point #2 is the current state. And recall that every reviewer at the time gave a poor review of the Prius and also spewed FUD about it. It took the Prius owners of the day to counteract this.

 

[JRP3]

The Model S and supercharging were never going to be the trigger for mass adoption. Superchargers are limited in number, and restricted in use, and the S is not a mass market vehicle.

 

[EarlyAdopter]

The impact of running heat is pretty minor compared to that kind of wind. Lots of open stretches of headwind on that route that night. Put 25 mph of wind on the nose and the car will draw power like it is doing 90 when you are only driving 65.

Perhaps Tesla should add a pitot tube to the Model S so it can take headwinds into account when projecting range.

 

[RDoc]

Perhaps Tesla should add a pitot tube to the Model S so it can take headwinds into account when projecting range.

That was my thought also. It could be used for gauging how close to draft a semi as well. :wink:

 

[gregincal]

I'm definitely not willing to spend time sitting around charging. However, an 80 mile radius is fairly large, and any further (where there's not a supercharger or I'm not charging overnight) we'll take my wife's car. Frankly, we'd never have taken my car on any longer drive previously (previous car was an Audi A3). We're actually more likely to now if convenient because the S is such a dream to drive.

I've always maintained when discussing the market for electric cars: Two car couples is hardly a limited market in the US.

 

[Robert.Boston]

I'm definitely not willing to spend time sitting around charging.

Most charging doesn't happen while you sit around, but while you sleep, eat, watch a movie, etc. E.g., I can drive from Boston to NYC, spend the day doing business, and drive home, and never spend any of my time charging. The car, of course, will be getting its 8 hours of charge while I work. It's a handy plus that I could stop off at the Milford CT supercharger on my way home, if I didn't get quite enough charge in NYC. By the time I go into the building there, use the restroom, and order a smoothie, and return to the car, it will have picked up an extra 40-50 miles of range.

In any case, @gregincal, if you're staying in the Bay Area, this whole discussion of cold-weather range is moot. It's only when temps get below freezing that the hit is really an issue. I've averaged over the 3,000 miles I've driven since December 14th 395Wh/mile. That includes, however, a lot of power used to heat the pack on my short commute before the iPhone app was released. I do much better now that I can preheat the car using shore power, and now that the temps are above the single-digits (F).

 

[Tempus]

I'm definitely not willing to spend time sitting around charging. However, an 80 mile radius is fairly large, and any further (where there's not a supercharger or I'm not charging overnight) we'll take my wife's car. Frankly, we'd never have taken my car on any longer drive previously (previous car was an Audi A3). We're actually more likely to now if convenient because the S is such a dream to drive.

I've always maintained when discussing the market for electric cars: Two car couples is hardly a limited market in the US.

So, taking the gas car on a roadtrip where you dont want to be bothered charging is certainly a legit plan.... However, let me offer a counter example.

This weekend, i took my family on a trip from northern virginia to northern NJ in my 60 kwh model s, and i didnt spend any time waiting on my car to charge.

We stopped at the delaware house friday evening for dinner after 120 miles driven. In the 40 minutes it took us to eat and use the restroom, we were back at over 170 miles of rated range. We stopped overnight at my inlaws place and i was full in the morning after using their 110 v outlet overnight.

We stopped for lunch and to meet friends at princeton the next afernoon where we charged on a j1772 outlet for a couple of hours while we ate and shopped and walked around the campus.

At our destination that evening (cousins house in north caldwell, 50 miles north) i was able to plug in again and charge for 5 hours while we were at the party that was the purpose of the trip.

Stayed at a hotel in princeton that night (chosen to break up the travel time AND for proximity to charging) and charged all night on j1772 again.

Full battery in the morning, quick stop at delaware to hit the restrooms (my daughter cant go 2 hours without having to stop anyway) and we had enough charge to get back home with 50 miles to spare.

Probably 15 or more hours charging (not counting the 110 overnight) during the weekend, but zero time wasted while waiting to charge, and total cost $3. (Princeton charger wasnt free). Id call that a complete success.

Maybe not for someone who was going to drive for 5 or 6 hours at a stretch, but our family driving patterns werent like that even in our ICE.

Tempus

Also, forgot to mention, the weather was miserable for most of my driving... Cold and rainy, although thankfully we missed the sleet/hail in the area.

 

[gregincal]

Just to be clear, I wasn't referring to charging at destination, that's fine. It's charging while on route that's the issue. Taking a break might be fine, but I don't really want to be constrained by it. And of course I get longer winter range here, but there's always a limit. For instance, this weekend we're going to the mountains. 200 miles, but a 6000 foot elevation gain, no real place to charge when we get there and below freezing temperatures overnight. It breaks my heart not to be able to take my S on our first weekend away after pickup, but it's just not practical. In the future I expect there will be a supercharger between me and the mountains that will make this possible (plus hopefully more places once there that have charging).

(Actually there is a supercharger between me and the mountains at Gilroy, unfortunately it's far too close to me to be of much use.)

 

[grisnjam]

Elon talks a bit about the cold and the Model S battery pack here:

Interview With Elon Musk On Tesla Model S Performance In Cold Weather - CleanTechnica

Ovidiu: What is the energy spent (per hour) to warm up the batteries to the chosen temperature, even in subzero conditions?


Elon: The battery actually loses very little energy when cold. Keeping batteries cold is actually the best way to preserve them! It only loses energy when keeping the pack warm for the convenience of the driver — so you don’t have to wait long to drive.

Ovidiu: Is this an active system that prevents battery failure due to extremely low temperatures, even if the car is not being used?

Elon: Once you start driving the liquid thermal loop transfers heat from the motor, gearbox and inverter to the battery pack, so not much incremental energy is needed at that point. We also close the radiator louvers at the front of the car (which has the dual benefit of lowering drag) and close the valve leading to the radiators, so the liquid loop doesn’t reject energy to the environment.

 

[JRP3]

He is a bit evasive and not actually answering the questions.

 

[J in MN]

Elon talks a bit about the cold and the Model S battery pack...

I don't believe what Elon said in that interview is accurate. I would be very surprised if the RAV4 EV is any different to the Model S - heck, Toyota did not even change the type of coolant that is used in the system.

In the RAV4, the DC-to-DC converter and the battery share the same coolant loop, and the charger(s), inverter and motor share another loop. The two loops are completely independent.

For another perspective on temperature impacts, see http://link.springer.com/article/10.1023%2FA%3A1004113825283. In short, at -40 °C, a 85 kWh battery becomes 4 kWh, and instead of 320 kW, it can deliver only 4 kW.

This http://www.panasonic.com/industrial/includes/pdf/ACA4000CE289-UR18650F.pdf Panasonic datasheet shows something similar, although they only go down to -20 °C.