A Case of Diminishing Return

Every time I read about someone wanting a 20 or 24 Kw (or larger) battery in their iMiEV, I do a mental calculation of the costs and efficiencies involved and it becomes obvious it wouldn't work for me - So far, the range of our car has never been any limitation . . . . we don't charge it everyday as it is and even when we do, we usually only charge it enough to go where we need - It gets a full charge only once every 2 or 3 weeks

Adding more battery power (and more weight) to any EV is a case of diminishing return - You not only pay a lot more for the extra power which you will use less often than the smaller capacity pack your needs actually require, you also get lots less return on your investment in the first place - The extra power doesn't take you as far (miles/Kw) as the smaller pack does so the efficiency of the car is reduced and the overall cost to operate it goes up . . . . and then remember you paid more for the larger pack in the first place

The quoted range for the Tesla gives us some hard facts in this regard. Consider the 208 mile range of the 60 Kw version of the Tesla model S - 208 divided by 60 gives you about 3.5 miles to the Kw. Move up to the 265 mile range of the 85 Kw version and you only get 3.1 miles per Kw . . . . and the extra 25 Kw of battery power you bought only gives you 2.28 miles per Kw (265 minus 208 is 57 divided by 25 gives you 2.28) Relative efficiency . . . . We get about 70 miles from 16 Kw's while the extra 25 Kw's in the Tesla is only good for 57 miles

Now, if you had a daily commute of more than 200 miles, this might be a good deal - You might actually be using some or most of those extra 25 Kw's every single day . . . . but it still lowers the car's overall efficiency, and if you seldom need to go 200 miles or more, then you're carrying around the extra and diminishing your efficiency essentially for nothing. Well, not exactly nothing - The extra 57 miles you get from the extra 25 Kw's which you only occasionally use will set you back about $10K. Unless you actually *use* those extra 57 miles quite often, you'll never get any return on your money . . . . and you lose a good deal of everyday efficiency just to haul the extra battery power around

Long story short - Buy the EV which has the range you require for your particular usage . . . . but understand that buying more than you'll need will really cost you, both in the upfront price and in the every day efficiency - Lower miles/Kw

Don

It's interesting with the rumors of Nissan making available a LEAF with double the battery (from 24kWh to 48kWh) for an "EPA rated" 150 mile range. The LEAF is EPA rated with its 24kWh battery at 75 miles range. Either they're using a different battery chemistry that is lighter or they've improved efficiencies somewhere.

All I know is that my i-MiEV won't make it to and from the airport on a single charge. Other than that, my car suits my driving needs, especially since my job hasn't sent me on a trip in a looooooooooooong time.

aarond12 said:

It's interesting with the rumors of Nissan making available a LEAF with double the battery (from 24kWh to 48kWh) for an "EPA rated" 150 mile range. The LEAF is EPA rated with its 24kWh battery at 75 miles range. Either they're using a different battery chemistry that is lighter or they've improved efficiencies somewhere.

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Or maybe more likely, someone other than Nissan has stated that a Leaf with a 48 kWh battery pack would have a 150 mile range based solely on the fact that the current Leaf has a 75 mile range. As Don has stated, merely doubling the battery pack capacity won't double the range.

I view this battery pack capacity issue as similar to the issue where so many in the U.S. buy much more vehicle than they really need and pay for their decision in increased initial cost and continuing higher fuel costs. For example, they buy a pickup truck because they think they would use it for carrying things, but in reality, they rarely use it for carrying things that they couldn't carry in a lighter, more fuel-efficient car. Or they buy a truck-based SUV because they think they need it but in reality, it is rarely more functional than a lighter, more fuel-efficient car. Or they buy 4WD when they rarely need it but pay for the additional fuel its heavier weight uses even when they drive in 2WD.

It would be nice if an EV's battery pack capacity could be temporarily increased for those few times that more capacity is needed. Maybe a battery-powered pusher trailer could be designed to be useful in this regard.

Don said:

The quoted range for the Tesla gives us some hard facts in this regard. Consider the 208 mile range of the 60 Kw version of the Tesla model S - 208 divided by 60 gives you about 3.5 miles to the Kw. Move up to the 265 mile range of the 85 Kw version and you only get 3.1 miles per Kw . . . . and the extra 25 Kw of battery power you bought only gives you 2.28 miles per Kw (265 minus 208 is 57 divided by 25 gives you 2.28) Relative efficiency . . . . We get about 70 miles from 16 Kw's while the extra 25 Kw's in the Tesla is only good for 57 miles

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Right! But it's also true, Tesla costs significantly less per mile (KM) of range then I-miev, even I-miev seems like a toy vs. model S.

alohart said:

It would be nice if an EV's battery pack capacity could be temporarily increased for those few times that more capacity is needed.

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http://eauto.si/en/new-projects/
Scroll down to 2. baterry range extender

Zelenec said:

Don said:

The quoted range for the Tesla gives us some hard facts in this regard. Consider the 208 mile range of the 60 Kw version of the Tesla model S - 208 divided by 60 gives you about 3.5 miles to the Kw. Move up to the 265 mile range of the 85 Kw version and you only get 3.1 miles per Kw . . . . and the extra 25 Kw of battery power you bought only gives you 2.28 miles per Kw (265 minus 208 is 57 divided by 25 gives you 2.28) Relative efficiency . . . . We get about 70 miles from 16 Kw's while the extra 25 Kw's in the Tesla is only good for 57 miles

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Right! But it's also true, Tesla costs significantly less per mile (KM) of range then I-miev, even I-miev seems like a toy vs. model S.

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How so?

Even using the EPA's 62 miles for our 16 Kw pack, that's 3.875 miles per Kw, while the Tesla only manages 3.5 or 3.1 depending on which version you're talking about. It's pretty hard for a heavier car to beat a lighter car when it comes to efficiency or cost per mile

Don

I think he means cost of the car vs. how far it can go.

263 miles for X sticker price of a Model S.
62 miles for X sticker price of an i-MiEV.

Not true cost per mile. Three times the sticker of an i-MiEV is equal to 186 miles of range, and more expensive than a Model S.

A little OT but it's apples and oranges between the LEAF/I-MiEV or the Tesla. Both the LEAF and the I-MiEV really fall down when you try to drive them at freeway speeds. The Tesla seems to do much, much better at higher speeds. I guess I should spill the beans here and tell you I got rid of my LEAF and replaced it with Tesla that I picked up last week. The reason I got rid of the LEAF instead of the I-MiEV was that the I-MiEV is a far better city car then the LEAF---better visibility, easier to get in and out of, easier to maneuver in tight spaces, and it carries a lot more cargo. The LEAF on the other hand was a very nice car to drive on the highway except you couldn't go very far as the range is only marginally better then the I-MiEV. The Tesla is a joy to drive longer distances. At 65 mph on the freeway, the car will run near its rated range of 265 miles. At 75-80 mph the range only dropped about 20 miles from rated. That's not a problem when you are starting out with 265 miles, but when you start out with a real world 62 miles (like I get in my I-MiEV when running A/C), loosing 20 miles is a bummer. Also, the I-MiEV isn't really the car you want to drive at 70+ mph even if you could because of it's high profile and narrow stance. The Tesla on the other hand isn't really the car you want to drive in the city--it is the total opposite of the I-MiEV.

Bottom line is you choose the car that meets your needs. And I am still amazed of what the I-MiEV can do for 1/5 the price of the Tesla. It's a lot of bang for the buck. If you need a Highway capable car with a lot of range I would look at something like the future Volt that should be out in 2016, or wait for the Outlander PHEV. Or just buy 5 I-MiEVs and space them on your route---You would have more range at less cost then the Tesla !

Wait, you had a LEAF? And traded it in for a Tesla?! And you have 2 and a half i-MiEV's?

Lucky!!!

PV1 said:

Wait, you had a LEAF? And traded it in for a Tesla?! And you have 2 and a half i-MiEV's?

Lucky!!!

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I don't think what Siai47 has is luck, it sounds like a lifetime of hard work and this is his reward for a job well done. I'm more reading this as a testament to the I-Miev over the Leaf. He could have dumped the I-MiEVs and kept the Leaf. Like Siai47, for those that can't afford a Tesla - the I-MiEV is a great electric vehicle.

The compromise I'd prefer would be a battery that's normally charged to 80% or so, with a 100% SOC option to enable for highway trips, etc...
Siai47- Congrats! I've sent your post to a pal who has both a Model S and a LEAF (and a pickup truck conversion). He's driven my i, will see what he says...

Don said:

Every time I read about someone wanting a 20 or 24 Kw (or larger) battery in their iMiEV, I do a mental calculation of the costs and efficiencies involved and it becomes obvious it wouldn't work for me [. . .] Long story short - Buy the EV which has the range you require for your particular usage . . . . but understand that buying more than you'll need will really cost you, both in the upfront price and in the every day efficiency

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Don, thanks for kicking off this discussion. It's on a topic near and dear to my heart, and one that comes to mind every time I read some writer or commenter decree that EVs are worthless without a 200 mile range. I don't understand how a whole product category can be dismissed out of hand when it meets the needs of millions of two-car households. EVs are a great fit for my circumstances, the i-MiEV particularly so, and I'm not alone. Many people could spend less money and have more fun with an i-MiEV, especially at the reduced 2014 prices, if only they weren't being scared away from EVs by so many confusing voices.

Teslas are great, but they're also very expensive for now, and unusually for a luxury marque, a LOT of that money goes into the hardware itself. Once they build their battery gigafactory and have a more vertically integrated operation with newer technology, they think they can deliver a decent family car for around half the price of a Model S. But that's still going to be around double what an i-MiEV will cost you next month, and the main reason is the i-MiEV's more modest battery pack.

The market totally gets why some people buy a Yaris when there's a perfectly good Camry sitting right across the showroom - so why is it so hard to understand that shorter-range lower-cost EVs can satisfy a viable market segment?

siai47 said:

... the I-MiEV is a far better city car then the LEAF---better visibility, easier to get in and out of, easier to maneuver in tight spaces, and it carries a lot more cargo. The LEAF on the other hand was a very nice car to drive on the highway except you couldn't go very far as the range is only marginally better then the I-MiEV…Bottom line is you choose the car that meets your needs. And I am still amazed of what the I-MiEV can do for 1/5 the price of the Tesla. It's a lot of bang for the buck.

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Amen to that! I recall similar explanations to friends when I bought the i-MiEV, noting that the LEAF and Focus Electric were cars that were better configured and equipped for trips they didn't really have the range to make. The Focus-E was a non-starter for many other reasons (price, availability, trunk space), but even the more competitive LEAF was just not as well-suited as the i-MiEV to the "townie runabout" mission best matched to their limited range. There are probably some buyers for whom the marginal range difference between LEAF and i-MiEV is a decisive factor, but I imagine they're in a tiny minority. That said, the LEAF is certainly a more nicely equipped and appointed automobile (I'm pretty sure my wife would have preferred it), so it all comes down to taste and values. For me, the i-MiEV's driving experience and utility (including its uncluttered user interface) were preferable to the LEAF's gadgets and comforts, but I can certainly understand why some would decide differently.

jray3 said:

The compromise I'd prefer would be a battery that's normally charged to 80% or so, with a 100% SOC option to enable for highway trips, etc...

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Well, that's exactly what the LEAF does, isn't it? Or is that your point?

For what it's worth, Mitsubishi has stated this feature would not have been worthwhile for the i-MiEV based on their battery chemistry and management system, implying that charging your i-MiEV to "100%" (or at least as far as it will charge) doesn't create the same level of problem as charging a LEAF to 100% (i.e., using the "full charge" option). While it wouldn't be a good idea to park the i-MiEV with 100% SOC for weeks, the normal ups and downs of nightly charging and daily driving shouldn't pose much problem, and we may be guilty of over-thinking things a bit in our attempts to improve battery performance. I suppose time will tell.

Don said:

Every time I read about someone wanting a 20 or 24 Kw (or larger) battery in their iMiEV, I do a mental calculation of the costs and efficiencies involved and it becomes obvious it wouldn't work for me - So far, the range of our car has never been any limitation . . . . we don't charge it everyday as it is and even when we do, we usually only charge it enough to go where we need - It gets a full charge only once every 2 or 3 weeks

Adding more battery power (and more weight) to any EV is a case of diminishing return - You not only pay a lot more for the extra power which you will use less often than the smaller capacity pack your needs actually require, you also get lots less return on your investment in the first place - The extra power doesn't take you as far (miles/Kw) as the smaller pack does so the efficiency of the car is reduced and the overall cost to operate it goes up . . . . and then remember you paid more for the larger pack in the first place.....

Long story short - Buy the EV which has the range you require for your particular usage . . . . but understand that buying more than you'll need will really cost you, both in the upfront price and in the every day efficiency - Lower miles/Kw

Don

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Don, the contrarian in me is begging to speak out. I don't know anyone - not a single person - whose road travelling needs never exceeds the range of the MiEV. And, unless you have made significant changes to your road travelling habits since you got your MiEV, I bet you at least sometimes need more range than the car offers. So that means everyone considering a MiEV, or Leaf for that matter, has to come up with a way to handle those longer travel days. Initially when I bought my MiEV it was my only car and I rented a car for longer trips. I figured that what I was saving on insurance and maintenance costs would make up for the cost of renting as needed. But that wasn't very practical, especially when my son moved back in with me. So I have added a gas car. I live in Albany and travel down to NYC/Long Island pretty frequently, so the gas car gets plenty of use. In addition, I often take rides from friends when I'm going on trips (usually golf related) that I can't get to in my MiEV. It really bugs me that I have to still depend on gas cars as much as I do, whether I'm driving my second car or getting rides from friends. I would love to have two electric cars, the MiEV for my every-day use and a longer range electric for the frequent trips that are outside the range of my MiEV. I would love to take my friends on trips in my electric car rather than having them take me in their gas cars.

But that doesn't mean that I wish my 2012 MiEV had come with a bigger, heavier battery. What I'm waiting/hoping for is a car that comes with a battery the same size/weight as the MiEV battery, but with three times the range, a fraction of the charging time, and which costs less than the MiEV battery. I think that day isn't too far off, either through improved battery technology or a combination of battery/fuel cell technology. If electric cars are going to expand beyond a niche market, they must be able to get an owner as far as he wants - with sufficient recharging infrastructure.

And by the way, your analysis that bigger battery means less miles per kw and therefore less efficiency, also applies to gas cars with bigger gas tanks. A vehicle with a 26 gallon tank is going to take you farther on a full tank, but less efficiently than a car with a 13 gallon tank. Yet we do have those. Car-makers have to meet consumer demand. As much as we complain about how little Mitsubishi has done to promote the MiEV, look at how much Nissan has done to promote the Leaf, and yet it's market share is microscopic, even with more range than the MiEV. I think all car-makers understand the limited attraction of a car that gets 75-85 miles range in good weather and 45-55 miles range in bad and that takes hours, not minutes to recharge.

I don't think the people who complain about the limited range of the MiEV are being unreasonable, I think they have a legitimate complaint about the limits of existing technology.

tonymil said:

Don, the contrarian in me is begging to speak out. I don't know anyone - not a single person - whose road travelling needs never exceeds the range of the MiEV.

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. . . . and the same could be said if you'd bought an 85Kw Tesla, it's just a difference of scale

So that means everyone considering a MiEV, or Leaf for that matter, has to come up with a way to handle those longer travel days.

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Yes, for sure. If you regularly need to go 100 or 150 or 200 miles, you need a different vehicle. Same thing if you need to haul a large or a heavy load or if you need to tow something. Very few vehicles can truly 'do it all' - Maybe that's why we see so many people who use a pick-up as a daily driver? My brother and I share an old diesel pick-up we bought for $4K with 140K on it ten years ago. At it's current rate of use, it will easily outlive both of us because it doesn't go more than 1500 or 2000 miles a year

It really bugs me that I have to still depend on gas cars as much as I do, whether I'm driving my second car or getting rides from friends. I would love to have two electric cars, the MiEV for my every-day use and a longer range electric for the frequent trips that are outside the range of my MiEV. I would love to take my friends on trips in my electric car rather than having them take me in their gas cars.

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If I were in your situation, the 'gas car' would be a Chevy Volt - A perfect compliment to your iMiEV which can do 75 or 80% of what you need . . . . and the Volt could do the rest . . . . and at least part of the time, do it without using any gas

And by the way, your analysis that bigger battery means less miles per kw and therefore less efficiency, also applies to gas cars with bigger gas tanks. A vehicle with a 26 gallon tank is going to take you farther on a full tank, but less efficiently than a car with a 13 gallon tank.

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How true! I laugh every time I see the Dodge truck commercials where they attempt to mislead everyone about how great their gas mileage is . . . . by telling us they can go 500 miles on a single tank - A single 32 gallon tank is the part they aren't disclosing - Fill that puppy up for $125 and you won't be raving about great gas mileage

I don't think the people who complain about the limited range of the MiEV are being unreasonable, I think they have a legitimate complaint about the limits of existing technology.

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I disagree. It is what it is and if that works for you, buy one - If not, get something else. It won't go 200 miles, it won't tow your travel trailer, it won't haul home 25 bags of Readi-Mix from the Home Center . . . . that's not what it was designed for. But it will do *at least* 75% of what the average motorist needs done on a daily basis and if you couple it with something which will do the other 25%, then you've solved at least 75% of your problem and that's a HUGE step forward

For us, it turns out that it's not a 75/25 mix - More like a 90/10 mix as can be attested to by the stale gas and trickle chargers we have with our other 2 cars

Don

siai47, congratulations on now having the best of both worlds with your Model S and i-MiEV! I've heard of at least one Tesla Roadster owner who bought an iMiEV as a daily driver. Despite our regularly needing to travel the 800-mile round-trip up to Oregon, I'm afraid that for us a Tesla Model S would simply sit unused the rest of the time. I approached Enterprise about renting an MS for a quick trip up and back, but not only is their rate awfully steep ($375/day), but after 100 miles they want 50¢/mile (but free SuperCharger access is included). Even at this rate, their one local MS was booked solid through April!

I agree with Don that buying a vehicle with more battery than is needed X% of the time (90%?) is wasteful both in terms of up-front and recurring cost. The range discussion amongst numerates boils down to individual needs within a usual operating radius of one's home and accessibility to recharging when exceeding that round-trip limit. We know how well the existing i-MiEV 's range suits most people's needs; however, using yesterday as an example, I was time-constrained and needed to go to a meeting 44 miles away. Not wishing to take a chance on public EVSE unavailability once I got there (I've been PIPed and VOLTed once too often) and not having CHAdeMO for a quick boost at one of QC stations along the way, I ended up taking the Gen1 Insight hybrid. Living in sprawling metropolitan areas such as San Francisco Bay Area or Los Angeles does put demands on an EV that would for many people be better-suited by BEVs with a range of around 100 miles. Brad Berman recently traded in his Leaf for a RAV4EV (120-mile+ range) despite it not having QC, and wrote an op-ed specifically about the range issue: http://www.plugincars.com/revisiting-how-much-electric-car-range-enough-maybe-120-miles-129591.html

To me it's appalling how few people truly understand their own vehicle usage in terms of mileage; all too often conversations cease abruptly when a mildly-interested party simply rolls their eyes and blurts out that they couldn't possibly be constrained by a vehicle that can only go 75 miles in one shot. This is further compounded by the knowledge that almost every household around here has more than one car and it's perplexing to me the lack of desire by people to even venture outside their perceived comfort zone and give a BEV a try as one of their cars. I see this as a lack of adventurous spirit in our ever-more cocooned society (goes along with the 'security' argument for a big SUV or pickup truck).

Maybe this 200 mile range ‘car’ w/ a 10KWhr battery at $24K will become popular. But it can barely hold a passenger.
http://litmotors.com/c1/
-Barry

Joe
The profit model is very strong in our society. And for the past 50-60 years, we have been told (via advertisement) bigger is better. Big SUV's, big trucks, big houses and Big Mac's. You must keep up with the Joan's to be a success. But in the end, we really do not needs the BIG stuff and only use a fraction of what the stuff can do. But we have been told, you need it just in case. And the reason we are told this is so companies can sell you more stuff. More profit.

This is not to say I believe less is better. It is just we should understand what our needs are and not the companies needs. Understand the true price of what bigger means to us. Yes, a <40 mile range is average for daily commute (well within a BEV range) but people want the security just in case they need to travel further. Which they might do a half a dozen times a year. And they do not understand that security has a price of +$2500 a year (fuel cost).

And like you, I wish they understand what security a BEV can give you every day and not just 6 times a year. Every day I do not need to worry about gas prices. Every day I leave the house fully charged. Every three months I do not need an oil change. And if I have the ability to place PV on my house, I do not need to worry about my own energy costs for the rest of my life.

And I think that this is why the elitist are not keen on EV's and therefore are not advertising the advantages of these cars. There is no profit in it. You can not profit from someone that is energy independent and therefore you can decide your own future and not what a company advertises what they believe you need.

A BEV, although having some limitations, have a great potential of making our individual lives freer, our environment greener and our world safer. And to me, that security is worth the extra planning required for those longer trips I would take 6 times a year.

Dave

An interesting $6800 USD 49 MPG ice vehicle, even if it is "vaporware" at this point.

http://www.eliomotors.com/

Kevin

Sorry to disagree with everyone, it must be a Brit thing, but as a happy I-MiEV driver for about a year I want one with a bigger battery.

I almost certainly do less miles than most I-MiEV'ers here and I got rid of two Honda Legends when I bought mine and haven't needed another vehicle for any journey since I bought it.

But, 60-80 miles without a rapid charging infrastructure to support it won't give me the freedom to travel that I had with my Legends.

The advantages of a larger battery are numerous, the batteries will last longer, the inability to sustain higher motorway speeds thus annoying others will go, I could use the extra kWh'rs to run my house off in the evening, and oh yes, a significant extra range without a significantly higher battery weight, 150-200 miles would be nice and I would be prepared to pay an extra £5,000 ish for the priviledge.

Wulnoth said:

. . . . 60-80 miles without a rapid charging infrastructure to support it won't give me the freedom to travel that I had with my Legends.

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That was 100% predictable before you bought it

. . . . a significant extra range without a significantly higher battery weight, 150-200 miles would be nice and I would be prepared to pay an extra £5,000 ish for the priviledge.

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You'd need a 60 Kw pack to do that and it would require significant changes to the suspension, wheels/tires and a more powerful motor - If you could do that for 5K pounds, I think lots of people would sign on - Oh, but you want it without 'significantly higher battery weight' too. THAT would really drive the price through the roof

An iMiEV with a $30K US price was a real slow mover - One with a larger battery for $45K would be a collectors item . . . . they might only sell half a dozen

Don