Optimal Battery Size and Driving Habits

[Chickenlittle]

Those who could afford the 60 jumped their order up to the 60, those who couldn't dropped out or didn't reserve until they thought it was clear the car would get made.

Sorry but your wrong about that. Tesla honored their orders and sold them the 60 at the 40 price with the car software limited to a 40 range. Even better for a fee they could unlock the software later to make it a 60

 

[FANGO]

Sorry but your wrong about that. Tesla honored their orders and sold them the 60 at the 40 price with the car software limited to a 40 range. Even better for a fee they could unlock the software later to make it a 60

I'm talking about before that announcement. Many people would have ordered the 40, but ordered the 60 instead because they would get it earlier - or at all, since it was becoming more and more clear that the 40 might not ever get produced. When Tesla announced they were discontinuing the 40, they gave the limited 60s to everyone who was left. But by that time, plenty of 40 reservations had already jumped-ship, either to another car or to the 60.

Giving limited 60s to the remaining 40 customers was a great move, good customer service, excellently handled by Tesla. They turned something which could have been a big negative for the company into a bit of a positive. It was well handled, that's for sure. But up until that part it hadn't been. There were a fair amount of angry 40 reservations out there before they announced that plan.

 

[pz1975]

Using miles driven PER DAY as an argument against needing more range is irrelevant. Of course very few people drive more than 300 miles per day.

What is important is not miles per day but how often someone needs to drive more than 300 miles in a day. If this only happens once per year then yes a smaller range EV is likely fine. But many people frequently go on weekend trips, road trips, etc that are more than 300 miles and thus would pay more to have to charge on the road less often.

I have had my Model S P85 for 6 months now and only twice have I had to use superchargers on trips. There have been other shorter trips in which I would have had to find a charger if I only had a 40 kWh battery. So technically I do not need my 85 kWh battery since my daily driving is less than 50 miles, but I would always go for longer range because when I do need it it makes my trip so much better and easier. I think the majority of EV shoppers would agree with this.

 

[FANGO]

Using miles driven PER DAY as an argument against needing more range is irrelevant. Of course very few people drive more than 300 miles per day.

What is important is not miles per day but how often someone needs to drive more than 300 miles in a day. If this only happens once per year then yes a smaller range EV is likely fine. But many people frequently go on weekend trips, road trips, etc that are more than 300 miles and thus would pay more to have to charge on the road less often.

I have had my Model S P85 for 6 months now and only twice have I had to use superchargers on trips. There have been other shorter trips in which I would have had to find a charger if I only had a 40 kWh battery. So technically I do not need my 85 kWh battery since my daily driving is less than 50 miles, but I would always go for longer range because when I do need it it makes my trip so much better and easier. I think the majority of EV shoppers would agree with this.

Read the statistics. That is covered. The proportion of cars driven over 300 miles in a day is minuscule. Averaged out over the whole car fleet, "once per year" is probably a gross overestimation of how often an average car gets driven more than 300 miles in a day. It's probably more like once every 5-10 years - if .05% of cars drive over 300 miles in a day (which, if anything, is a high estimate, considering 300 miles isn't even on the charts), then each car on average drives over 300 miles once every 6 years.

The majority of EV shoppers don't have an extra $20,000 to spend on saving 30 minutes on one trip a year. That is an awfully high valuation for your time.

 

[daxz]

Statistics are great in how you can make numbers for what you want.

My log showed that I only drove 30 miles per day, *on average*. There's your data. But on three of the days, I drove *over* 100 miles, one day reaching 180 miles. Would a Leaf work for me? No.

I think roblab's approach is good - its not the average daily trip that is desired for an EV but the max potential range.
Using the NHTS data at NHTS Data Extraction Tool

populating parameters:
year: 2009 (newest data set)
mode: POV (personal vehicle)
Miles: 100+
(below shows all mile ranges in Millions)

Year	Mode	Miles	Person Trips	Person Miles	Vehicle Trips	Vehicle Mile
2009	POV	Under 1 mile	31,269.25	14,255.16	21,993.37	10,116.28
2009	POV	1-2 miles	35,846.10	37,530.99	25,922.51	27,109.50
2009	POV	2-3 miles	39,635.35	79,652.09	28,632.82	57,556.35
2009	POV	3-4 miles	32,264.09	96,975.49	23,084.47	69,384.27
2009	POV	4-5 miles	22,947.86	91,826.20	16,579.68	66,344.43
2009	POV	5-9 miles	70,510.95	455,247.32	50,890.79	329,582.49
2009	POV	10-14 miles	32,002.50	365,108.73	23,354.03	267,284.25
2009	POV	15-19 miles	18,233.33	295,847.19	13,556.43	220,736.09
2009	POV	20-24 miles	11,185.23	237,525.76	8,152.94	173,544.93
2009	POV	25-29 miles	6,671.72	174,544.80	5,111.29	133,905.92
2009	POV	30-34 miles	5,024.59	155,816.63	3,657.63	113,904.41
2009	POV	35-39 miles	3,059.21	110,552.30	2,251.31	81,337.67
2009	POV	40-44 miles	2,418.53	99,259.86	1,619.63	66,446.01
2009	POV	45-49 miles	1,676.10	77,034.94	1,131.23	52,026.52
2009	POV	50-74 miles	3,881.70	227,027.28	2,560.50	149,126.22
2009	POV	75-99 miles	1,408.70	118,799.97	  825.70	69,339.67
2009	POV	100+ miles	3,114.55	661,163.39	1,658.09	357,366.43  <---

the number of trips is 1,658M for 357,366M miles or about ~215 miles on average for vehicles driving over 100 miles.

Yes, these 100+ miles trips are 0.7% of the trips recorded.

 

[FANGO]

the number of trips is 1,658M for 357,366M miles or about ~215 miles on average for vehicles driving over 100 miles.

Yes, these 100+ miles trips are 0.7% of the trips recorded.

So on average, each car will drive over 100 miles twice per year (.7% = 1/142, 365 days in a year, so twice a year). Or one roundtrip over 200 miles per year. So either a) get a Leaf-class EV and rent a car once/twice per year (many people rent cars for long trips anyway), b) quick charge in your Leaf-class EV for 30-60 minutes on those few trips, or c) get a Tesla and don't even have to quick charge that unless you're in an even more exclusive range group. The other option, of course, is to pay tens of thousands of dollars for an enormous battery pack which you'll only fully discharge once a year, saving yourself the aforementioned hour or two when you are on a long drive and likely stopping to sightsee or eat anyway. I do not think many consumers will make that choice. Keep in mind that most of us here, as Tesla owners, have the money to throw at more expensive cars if we think they will be better. Most people do not.

This is why the solution is not ever-increasing range numbers, but increased access to quick charging, which is why all companies are focusing on quick charging, because they've seen these statistics as well. And increased access to quick charging is the step forward, not unusably enormous battery packs.

 

[kcveins]

I don't think it's absurd at all. Early adopters and opinion leaders can set the tone for society's take on a product, absolutely. If early adopters all wrote blogs about how the thing doesn't work because it doesn't go far enough, and then media got hold of this idea and reported it over and over, that would certainly chill the general public's feelings about the car. The Model S does well because it's universally loved by the early adopters, and word-of-mouth, the most valuable form of advertising there is, has been phenomenal. The same holds true for the Leaf and Volt. People generally love their EVs, and that's driving demand.

But I did say in my other comment earlier that manufacturers have an influence on it. Traditional manufacturers want to talk about range as much as they can, because it's in their interest to play up the "disadvantages" of EVs. Or to create the perception of a disadvantage when the thing in question is actually an advantage (not having to go to gas stations, having the car be full when you leave the house).

If Tesla's official mission is to expedite EV adoption (which it is), then Tesla needs to be careful about making the general public feel that range is the most important question about an EV. I think they do a fairly good job about this, and the focus is largely on making a great high-performing car which just happens to be electric, and which can get anywhere because of the supercharger network, regardless of what "range" car you get. But this is why I feel like discontinuing the 40kWh was a step backwards, because it sends the message that the 40 wasn't "enough." I understand it from a business perspective, particularly now because of the supply constraints, but it does not aid the case of greater EV adoption. It could well make the lower-range but affordably-priced EVs look inferior, such that people may put off buying decisions for a few years. Luckily, the Leaf is still selling very well, and it seems people haven't been too put-off by it. But it needs to sell better. We need more EVs on the road now, not years from now. We need to stop burning oil.

I drive 50 miles for work 3 days a week, 70 miles one day and 100-120 miles the fifth day. I was seriously thinking of just getting the 60, but got the 85 kWh instead. IF Tesla made a 60 that went far enough in ALL conditions, then I would have been best getting that. However, this winter in Chicago was brutal (had 25+ consecutive days below 0) and a full range charge in my 85kWh with the heater running gave me only 140 miles. If we are to use an electric car without compromise (ie not driving 55 mph on freeways when everyone else is going 70 or greater) then the REAL range needs to be that. Honestly, you need a 150 mile range in all conditions, not in the nice warm conditions that you all see in the west coast.

 

[InTheShadows]

In agreement with AudubonB. I may not drive 300 miles every day, but when I do (about every other month) I do it in one day, to get to a work place. Wouldn't do to be late for work, and it wouldn't pay to have to get a hotel along the way just to get paid.

So for me too, 300 miles range just about takes me to work (if driving carefully, without snow etc) but without any decent way to charge once there. One gas station offers two 230V16A single-phase outlets for max two hours at a price (unless their own EV occupies them).

That was one reason for my hesitation to get a Tesla; another was the lack of fast charging en route. This may change soon, but not soon enough or with enough certainty, so I cancelled my order. :-(

It hurts to be one of THOSE 1%!

It feels great to be a 1%er too. We have had our car 6 months exactly and it has 12.8k miles on it. Thursday I will be driving at least 240 miles round trip. I have had a few trips where I took the Golf because of superchargers that are not in service yet or going into areas where there are no super chargers. I have at least once a week where I am in the double digits of remaining range and I range charge at least once per week.

 

[JRP3]

In conclusion: gas cars benefit from large tanks even when they are never used on long journeys, whereas EVs have little benefit from large batteries if they are never used on long journeys.

More power/performance, longer life span from shallower cycling and lighter loading, greater usable capacity in all conditions, and over the life span, and faster high power charging. All independent of long journey use.

 

[Krugerrand]

By the way, notice that all of this conversation is ignoring superchargers. More superchargers = less range needed, not more.

Yes and no. There's a balance that makes most people happy between range and need to refuel. If your statement was inherently true, then we'd all be driving ICE cars and trucks with gas tanks of the size used for motorcycles, but nobody wants to have to stop at a gas station every 50-100 miles even though we've got hundreds of thousands of them - they just don't and the same will hold true for EVs in the long run. The Model S 40 was a hobbled car per the CEO, who is the guy that knows what he's talking about. Great decision to not even produce them and clearly the consumer agreed as evidenced by the low order rate - early adopter or not.

Making this post relevant to the thread:

Failing to not listen to the consumer AND your (CEO's) gut instinct = bad reviews for cars with that battery = brand damage = (at the very least) short term downward pressure on the stock = not having been able to do two rounds of funding to pay off the DOA loan and begin Gigafactory plan = etc., etc., etc., and very likely significant long term investment changes. Not to mention the snowball affect of possibly not making the gross profit margin targets and all that that entails.

There's a very specific path Tesla has chosen to follow for the big picture. The 40 was not part of it.

 

[Auzie]

More power/performance

This is critical to sell the cars. This alone far outweighs any cost benefit of having smaller battery.

I expect price differentiation on battery size to melt into insignificance in the future.

 

[Jack6591]

This is critical to sell the cars. This alone far outweighs any cost benefit of having smaller battery.

I expect price differentiation on battery size to melt into insignificance in the future.

Well said.

 

[FANGO]

Correct, it was lack of demand..

Very much not correct, as addressed above.

 

[Norbert]

Very much not correct, as addressed above.

I think you are confusing cause and effect with your explanation (above). Tesla didn't sell them because only few wanted them in the first place. Plus, Tesla/Elon wants to sell a car that is really a good value, so he/they were probably glad about it, in a way. If the big demand had been on the 40 kWh, as you suggest it should, then they would have adapted to demand. (Being limited by battery cells later on, it would have allowed them to sell more Model S).

 

[Neech]

All this talk about range should be moved to the Battery area. Let's get back to the topic of this thread. Moderator?

 

[Norbert]

The Leaf has exploded in sales. They've sold 120k worldwide, I think. And that's from a bunch of dealers which aren't at all fully focused on selling them. And of course there are all the other low-range EVs from other manufacturers, if we're just doing a comparison of smaller batteries vs. larger ones. Compared to, what are we at now, 40k Model S?

Leaf's US sales are about 1,400 per month. If Tesla wasn't production limited, they might sell similar numbers (probably actually did before starting Europe and then China distributions). That in spite of being a much higher end car. Tesla simply started later, and currently is production limited. (And needs to build stores, service centers, etc, worldwide.)

 

[hcsharp]

...WHY, then do gas cars come with a 300 mile range?
People may not need 300 mile range, but it's the minimum we think we need.

No. Gas cars have 300 mi range because buying gas sucks and 300 mi is about the most often anybody will tolerate those smelly places.

...In conclusion: gas cars benefit from large tanks even when they are never used on long journeys, whereas EVs have little benefit from large batteries if they are never used on long journeys.

+1. Most people are so used to the gas paradigm that they can't grasp this concept until they experience it for a week or two or three.

... Also, they come with larger tanks because people don't go to the gas station every day, because going to gas stations sucks. ...

Like you said, people do not need 300 miles. They think they need 300 miles, but they don't. They think this because they've been told by traditional auto companies that range is important, ...

When I first got my Tesla I treated it like a gasser for a week or so. I didn't plug it in every night. I charged it when it started to get low. Made sense to me because that's what I've always done with gas. Finally it dawns on you that it's more like a cell phone than your old car. Most people don't get this until they do it. You can explain it all day long, but it's too different from what they're used to for them to understand. That's why it's so easy for legacy automakers and oil companies to convince people that range is important and to instill range anxiety.

Obviously electric range is important for occasional long trips and people with situations like AudubonB, traveling salespeople, etc. But for gas the reasons for 300 mi range are different than for EVs.

 

[ItsNotAboutTheMoney]

More power/performance, longer life span from shallower cycling and lighter loading, greater usable capacity in all conditions, and over the life span, and faster high power charging. All independent of long journey use.

Or as I like to put it ...

Capacity ~ range ~ performance ~ charging mph ~ 1/discharge rate.

Performance needs more motor and inverter.
Extra capacity means some extra weight.
But overall more capacity is more awesome.

You can have different chemistries and designs with different characteristics, but extra capacity takes strain off the chemistry so helps with lowering the cost.

 

[jerry33]

Obviously electric range is important for occasional long trips and people with situations like AudubonB, traveling salespeople, etc. But for gas the reasons for 300 mi range are different than for EVs.

You're right, the reasons for 300 mile range in a gas car are different.

Range is important in an EV for any number of reasons, not just long trips:

1. When the power goes out for a day or three. (That seems to be happening more often.)

2. When you get called back into work. (Saying, "I'll be there in two hours because I have to charge for an hour" is not likely to be acceptable to the boss.")

3. When your wife has a flat. (Saying, "I'll be there in two hours because I have to charge for an hour" doesn't win any points.)

4. When you want to go to a neighbouring city for some event. (I've had some of my Leaf owning friends say they weren't going to an event because of this. It's just crazy to have a car that won't let you do what you want it to do.)

The most annoying thing has to be hunting for a charging station because your car doesn't have enough range to make it back or not going because it's more than half the range that your car has. With the S85 I've never had to charge away from home except for trips--and then the charging stops are planned. And I haven't heard any "I told you so" either.

 

[Mario Kadastik]

I think we've argued about this in another thread, but here we go again.

Until the charging network isn't fast and dense enough the lower batteries won't prevail. That means approximately the Gen-III timescale, not before. A large part of EU and Asia still has a very limited charging network from Tesla even though it looks to be expanding rapidly. There are plenty of people who need to take once in a week or once or twice in a month trips to another town and back. The single distance might be in the 100 mile range, but you usually have to consider the return trip so 2x that. In addition if you're not living in California you have to take into account how far you can go in the dead of winter with a blizzard. This winter we had three weeks of -22C and snow. The cars range doesn't halve, but getting over 200 miles is so-so, especially if you stop and let the car cool down again (i.e. couple of hours meeting or full work day even). That means that your ideal weather 100 mile car would be a 60 mile car in the winter. The smaller the battery, the relatively higher the impact of heating etc needs (a 6kW heater is nothing to an 85kWh Tesla, but would be quite a sucker for a 20kWh battery car eating up 60% of the battery for a 2h trip, basically you couldn't got 2h in it).

If you only buy the car to drive during perfect weather, then the listed ratings might be fine for you, but if you buy the car to be your sole driver, then you need reserve buffers for bad weather and irregular trips. I've had multiple occasions where I needed to suddenly go long distance (for example when my wife got a call that her dad died and we left the same minute to another town to be with her mother ~190km away).

And renting an ICE for longer road trips when your daily driver is an EV seems an abomination. I go to dog shows for example and that includes abroad, taking 400-700km road trips without any Tesla superchargers is hard, but would be impossible with a smaller battery. I still do it right now only during summer and am lobbying Tesla to get at least 1-2 superchargers to allow cross-country driving in the region.

Also, bigger battery comes by default with improvements. Your milage to degradation ratio is going to be far better as you do less full cycle equivalents to travel the same distance. Your other usage in relation to drivable usage improves (the heating example above) and your battery charge rate is going to be better. Also, with a bigger battery you can reduce the window of daily usage and put it in the optimal region (i.e. 30%-70% region) extending the battery life further.

So I think Tesla will never bring back the 40kWh battery for the Model S as the time it takes to make 40kWh feasible charging network wise is the same time it takes to bring out the Gen-III vehicle. That will be the cheaper and shorter distance car (though I'm fairly sure it'll have longer distance and performance models as well). The S will be the high end car along with X and will more likely feature bigger battery packs in the future. So I'd not be surprised if Tesla discontinues the 60kWh model when they introduce a 110kWh or similar batterypack. From what I have heard form a reliable Tesla source in EU so far the mix of 60 vs 85 is 5% to 95% so it makes sense to drop the 60kWh pack when a new pack is introduced.

Also, you can't always destination charge. A simple example is that you discover the hotel has screwed up the grounding. So having a buffer is a good thing so that you can make it to your destination and back to a charger.