eevBLAB #63: How Affordable Are Electric Cars?

[wraper]

Most ICE vehicles don't require engine replacements. When there is a major problem specific components can be replaced rather than the whole thing. That's mostly NOT going to be the case with the electric motors or batteries.

Really? That only happens when engine still has low mileage. When it's over 100k-150k miles or often even less, most modern engines become irreparable scrap.

I had an old (1980) Volvo 240 that the odometer broke on just short of 400K miles.  I sold it and the new owner had it for about 5 years and then I got it back, still running but beyond repair for other reasons.  I've ridden in Priuses (Prii?) used as airport shuttles that were into the 400K mile range.  If you take a more or less ordinary car and use it a lot and maintain it a bit, you can rack up a lot of miles.

Because it was old Volvo. It's a bit different in US but in EU it's most common that a lot of power is salvaged from least engine volume. Such engines last only if impeccably maintained and not stressed (usually does not happen) and even then not that durable. Of course there are still engines which last but many do not. Cylinder boring (with all it comes with) on worn out engine to extend lifetime is possible but it's expensive, especially in 1st world countries. It certainly does not qualify as simply "when there is a major problem specific components can be replaced rather than the whole thing". Often may consider just as beyond economical repair.

[james_s]

I had an old (1980) Volvo 240 that the odometer broke on just short of 400K miles.  I sold it and the new owner had it for about 5 years and then I got it back, still running but beyond repair for other reasons.  I've ridden in Priuses (Prii?) used as airport shuttles that were into the 400K mile range.  If you take a more or less ordinary car and use it a lot and maintain it a bit, you can rack up a lot of miles.

I'm on my second interior on my '84 240, it's only got about 230k on it though. I had a '87 740 Turbo that had 330k on it when I was rear ended by a semi. My mom still has the '86 240 she bought new, it's also on the second interior but with 350k miles the engine has never been opened. Those old Volvo redblock engines were bulletproof.

[tom66]

Your 'debunking' contained too many ifs that there just wasn't enough meat to sink my teeth into. For example the assumption that at night most power comes from nuclear. How about charging during the day at work? Also you choose an unrealistically low EV power consumption figure. The reasons people get low power consumption for EVs is because they mostly use them for short non-highway trips. But in those cases a hybrid will also be much more efficient.

I didn't make that assumption at all.

I simply took the UK carbon-dioxide average for CO2 per kWh of electricity (at the plug socket) which is around 250g per kWh.  At night, CO2 emissions *generally* fall. This is because, in part, demand at night is lower, so the available renewable and nuclear energy can support it with much lower carbon intensity. However, the calculation wasn't made with the assumption that you charge at night; that's simply a possible bonus. 

I then compared two efficient vehicles, for their given class - a Prius and an e-Golf.  So I'm giving the petrol car its best chance by selecting one of the more efficient, common petrol vehicles. The e-Golf is far from the most efficient EV.  It's not bad, but mostly its efficiency comes from being a relatively average hatchback.  If you want to run the comparison with the less efficient Leaf, then sure, it's a little worse, but only 10% or so more. 

The EV only loses out when you take something like a Tesla Model S, a large and heavy vehicle, run it off 100% coal, and then compare it to a 0.9L VW up!.  The Tesla might be about 25% worse then, but that's a ridiculous comparison. If you were to compare it to something more reasonable, a vehicle in its class such as a BMW 530d, which has emissions of 140gCO2/km, then it's *still* better than that, *even if it is powered entirely by coal*.

I'll run another comparison:

Burning 1L of petrol produces 2.31kg of CO2.  There are other emissions that aren't accounted for in this figure, such as the emissions produced in the production/extraction/refinement of petrol, and the distribution, usually by tanker truck. And I couldn't get an accurate figure for these.   But it's going to be worse than the stoichiometric figures.

VW e-Up! vs VW up! 1.0L petrol 75PS

11.7kWh/100km [1] vs 4.5L/100km [2].

CO2 emissions for 100km are therefore (on UK domestic electricity) 2.92kg vs 10.4kg.  A reduction of ~72%.

[1] https://www.volkswagen-newsroom.com/en/e-up-3497
[2] https://en.wikipedia.org/wiki/Volkswagen_Up#Engines

[sokoloff]

Properly taken care of, virtually any modern ICE or EV battery will last the life of the car, so this is a non-issue.

This is a little bit like saying "virtually any human heart will last the life of a person."

[EEVblog]

Still trying to find a used LEAF. It seems to be either sub $20k for a 2014 with 24kW pack, or $33k+ for a 2016 with 30kW pack.

[tom66]

Still trying to find a used LEAF. It seems to be either sub $20k for a 2014 with 24kW pack, or $33k+ for a 2016 with 30kW pack.

It's kWh, not kW.  The motor in the Leaf is rated for 80kW in the older models, but EV batteries are always capacity rated in kWh or Ah. 

I think the issue is that the Leaf was introduced very late into the Aussie market, so there's many fewer used examples.  I can find a used 2011 Leaf for £7,000 GBP - about $13,000 AUS.  But the market is saturated because many were given away on very generous lease/contract purchase deals (a colleague of mine was leasing one, all in, for £99 a month, 8000 miles per annum, cheaper than even the cheapest petrol cars.)  I don't think the same think happened in Australia.

[Towger]

Still trying to find a used LEAF. It seems to be either sub $20k for a 2014 with 24kW pack, or $33k+ for a 2016 with 30kW pack.

If you want to pay shipping, here is a 2015 for under 8k euro. If you don't mind high mileage.

http://www.adverts.ie/18678533

[coppice]

But the market is saturated because many were given away on very generous lease/contract purchase deals (a colleague of mine was leasing one, all in, for £99 a month, 8000 miles per annum

Do you know how that worked? I know people in the US who got deals like that. "$110 a month, no fuel costs, I can park at the chargers at work, avoiding a long walk across the car park, and we get an extra car for use around town" seemed like an irresistible offer to some people who were not even looking for an extra car. I don't see how that price makes sense to Nissan, though, even with lots of government incentives.

[nctnico]

Most ICE vehicles don't require engine replacements. When there is a major problem specific components can be replaced rather than the whole thing. That's mostly NOT going to be the case with the electric motors or batteries.

Really? That only happens when engine still has low mileage. When it's over 100k-150k miles or often even less, most modern engines become irreparable scrap.

That's the most unintelligent thing you've ever written and has no basis in reality.

I agree. This might have been true in the 70's but nowadays you can get 300k km from any car engine if you replace the oil in time and don't do stupid stuff like continue driving when there is a red alarm light on.

[coppice]

Most ICE vehicles don't require engine replacements. When there is a major problem specific components can be replaced rather than the whole thing. That's mostly NOT going to be the case with the electric motors or batteries.

Really? That only happens when engine still has low mileage. When it's over 100k-150k miles or often even less, most modern engines become irreparable scrap.

That's the most unintelligent thing you've ever written and has no basis in reality.

I agree. This might have been true in the 70's but nowadays you can get 300k km from any car engine if you replace the oil in time and don't do stupid stuff like continue driving when there is a red alarm light on.

300k km == 187.5k miles, which doesn't seem a whole lot bigger than the original poster's 150k mile figure.

Car engine life has a lot to do with usage patterns. In the US, where the average journey is longer than in Europe or Asia, you see many many cars with extreme mileage figures that are still performing well.

[nctnico]

100k miles = 160k km. Half of 300k so no, Wrapers numbers are way off.

[wraper]

Still trying to find a used LEAF. It seems to be either sub $20k for a 2014 with 24kW pack, or $33k+ for a 2016 with 30kW pack.

30 kWh battery is complete crap which degrades very fast. Much worse even than not that good 24 kWh battery. There is very high chance there will be less capacity left than if you buy older car with 24 kWh battery.

[wraper]

100k miles = 160k km. Half of 300k so no, Wrapers numbers are way off.

FWIW many engines die even faster if not properly maintained. Maybe my numbers are a bit low, but they were meant in general, not proper care scenario. Then there also is transmission which wears out too.

[tom66]

But the market is saturated because many were given away on very generous lease/contract purchase deals (a colleague of mine was leasing one, all in, for £99 a month, 8000 miles per annum

Do you know how that worked? I know people in the US who got deals like that. "$110 a month, no fuel costs, I can park at the chargers at work, avoiding a long walk across the car park, and we get an extra car for use around town" seemed like an irresistible offer to some people who were not even looking for an extra car. I don't see how that price makes sense to Nissan, though, even with lots of government incentives.

I think they were losing money on every car leased.  There were some benefits in getting tradeable carbon certificates but I doubt ultimately worth it.

The idea was to get the cars out there so people recognised them and saw that EVs (particularly EVs from Renault-Nissan) will be viable.  And it has worked, to an extent; they are the best-selling EVs in the world, Tesla just behind.

Almost an opposite of the Roadster model (start high and then go lower.)

[tom66]

30 kWh battery is complete crap which degrades very fast. Much worse even than not that good 24 kWh battery. There is very high chance there will be less capacity left than if you buy older car with 24 kWh battery.

This is why I would never buy a Nissan EV or any EV without liquid-cooled batteries with intention of using it as a primary vehicle. For low mileage low stress driving it is viable, but not high mileage.  Ford had the same issue in the USA with their PHEV Energi batteries.  Air cooled and as a result, at 50% SOH after 5 years, unacceptable.

Air cooling means a fan to blow air over the cell stack, but does very little for internal heat production.  Liquid cooling in most EVs implies metal cooling plates between each cell or at least each pair of cells to remove the heat directly from the cells.

Then add in Rapidgate - Nissan batteries that don't like fast charging more than twice - hmm...

Tesla batteries last.  So far the LG Chem batteries in other EVs last well too.   Nissan batteries don't seem to last, at all.

Leaf is a city EV; treat it as any more and you'll have a bad time I think.

[james_s]

Properly taken care of, virtually any modern ICE or EV battery will last the life of the car, so this is a non-issue.

This is a little bit like saying "virtually any human heart will last the life of a person."

Perhaps a bit, but my point is that most cars get scrapped with the engine still in serviceable condition. They are scrapped because the paint is shot, the interior is falling to bits, transmission is acting up, accessories are broken, body rust or any number of other "death by a thousand pinpricks" situations where it would cost more to repair all the minor problems they have allowed to stack up than they perceive the car being worth. Then there are all the cars damaged by accidents. If a car is scrapped when the engine is still usable then the engine has lasted the life of the car and a longer lasting engine would not have extended the life of the vehicle.

I think you would find very few cars are junked because the engine is bad, and with most that are it is not really worn out but was destroyed by catastrophic incidents like a broken timing belt or loss of oil or coolant.

[floobydust]

I find a car's life is limited by body rust, in Canada salt and sand are applied to icy winter roads and the body corrodes faster than say near the ocean, or wet tropical climates. The ICE seems to die around the same time ~300,000km looking at dead cars in the wrecking yard. DeLorean was right using SS 
So an EV's extra drivetrain life is probably not usable. Hmm.

EV batteries with a lifetime rated in miles seems silly. You don't know if the miles were soft and easy or hard and fast. I can't make distance relevant to discharge depth and rate and number of cycles and heat the battery has experienced.
I'm interested in ESR testers for batteries and wouldn't they tell you a lot about the pack's health? Before you buy used, one test to do instead of speculative psychology, hope and optimism.

[nctnico]

I'm interested in ESR testers for batteries and wouldn't they tell you a lot about the pack's health?

I have looked into this a couple of years ago. The problem is that there are several aging mechanisms at play and you can't just look at the ESR (or even better: complex impedance) to see what the battery pack's health is. At most you can do a full cycle test and see how much of the capacity is still there and based on the mileage of the car try to extrapolate how much more you can get from the battery pack. However wear on a battery pack is severely influenced by how it is charged, how it is discharged and at what temperatures this happened. So you can get to a number with +/-30% accuracy.

[sokoloff]

I'm interested in ESR testers for batteries and wouldn't they tell you a lot about the pack's health? Before you buy used, one test to do instead of speculative psychology, hope and optimism.

Most of the EVs do a periodic battery health evaluation and store the results in the battery management system.

Many of these have been reverse engineered and you can get a readout using 3rd party tools (in addition to and often with more detail than what's displayed on the vehicle instrument cluster).

[tom66]

I'm interested in ESR testers for batteries and wouldn't they tell you a lot about the pack's health?

I have looked into this a couple of years ago. The problem is that there are several aging mechanisms at play and you can't just look at the ESR (or even better: complex impedance) to see what the battery pack's health is. At most you can do a full cycle test and see how much of the capacity is still there and based on the mileage of the car try to extrapolate how much more you can get from the battery pack. However wear on a battery pack is severely influenced by how it is charged, how it is discharged and at what temperatures this happened. So you can get to a number with +/-30% accuracy.

EVs manage to measure battery capacity just fine by coloumb counting. To do this accurately, the pack needs to be fully charged and fully discharged periodically.

Issues occur when the pack remains mostly in the middle SOC environment because it is never fully charged or fully discharged and so the BMS hasn't been able to sort weak cells (which generally define the lowest discharge voltage) or measure overall capacity. To get the most accurate range measurement from an EV pack it is probably best to subject it to a long, relatively high load motorway drive (to represent higher average power draw from the pack) until it is as depleted as reasonably possible.  Testing on a dyno is also possible, but would take a relatively long time. 

[nctnico]

I'm interested in ESR testers for batteries and wouldn't they tell you a lot about the pack's health?

I have looked into this a couple of years ago. The problem is that there are several aging mechanisms at play and you can't just look at the ESR (or even better: complex impedance) to see what the battery pack's health is. At most you can do a full cycle test and see how much of the capacity is still there and based on the mileage of the car try to extrapolate how much more you can get from the battery pack. However wear on a battery pack is severely influenced by how it is charged, how it is discharged and at what temperatures this happened. So you can get to a number with +/-30% accuracy.

EVs manage to measure battery capacity just fine by coloumb counting. To do this accurately, the pack needs to be fully charged and fully discharged periodically.

You are missing the point. The pack's health goes way beyond just the capacity. What you want to know is how much wear the cells have experienced and how soon they will break. Ideally you want to know this for each individual cell because like it or not each cell will wear in a slightly different way; they aren't 100% identical. The weakest cell in a string (say a sub section of a battery pack) will determine how long the string will remain working. There is still a lot of research going on in this area and we are likely to see way more sophisticated battery management hardware.

A capacity measurement is just a momentary measurement. It will say nothing about the growth of dendrites for example.

[tom66]

Dendrites short the cells.  That's fatal.  But no pack should be forming dendrites at all, because that indicates charging has exceeded rated temperatures (usually too fast of a charge when cold.) 

Pack health is dominated by capacity and ESR.  Both of these are measured by the BMS system, but require the pack to be discharged to find the weakest cells, as the ESR of li-ion cells has a SOC-dependent characteristic (voltage drop is higher when state of charge is lower.) And to measure the overall capacity you then need to charge the pack up again.

[nctnico]

Dendrites short the cells.

Not immediately and that is where the problem lies and why looking at the ESR and capacity isn't enough to judge how long the battery pack will last.

[EEVblog]

Leaf is a city EV; treat it as any more and you'll have a bad time I think.

You can't really treat it as anything more, it doesn't have the range.

[EEVblog]

Still trying to find a used LEAF. It seems to be either sub $20k for a 2014 with 24kW pack, or $33k+ for a 2016 with 30kW pack.

It's kWh, not kW.  The motor in the Leaf is rated for 80kW in the older models, but EV batteries are always capacity rated in kWh or Ah. 

Yes, I know, I'm being lazy. It's common in the industry to drop the h, most of the ads do, and common in EV forums too when talking about a known type.