Electric cars and cooling drag

[ME_Andy]

Yep, I own a Leaf. It's lost maybe 15% of its capacity in 6 years (in Texas).

[Isaac Zachary]

Originally Posted by ME_Andy

Yep, I own a Leaf. It's lost maybe 15% of its capacity in 6 years (in Texas).

Did you buy it new or used?
If used, is that 15% of the total or 15% of what it had?
Is this car garaged?
What kind of driving is done with it, how many miles a year, how many long trips, etc.?

You see, to a new owner that might not seem like a bad thing at all. In 12 years your car will finally be needing another battery (unless used for very short trips) and to most people by the time that happens they'll have moved on or it becomes a second car for those short trips here and there.

But what about the used car market? I know I don't represent every used car buyer out there, but I think my experience is somewhat normal. Here are some cars I've bought and used quite extensively:

• 1993 Mazda 323 for $250. The head was warped and needed a radiator. For about $500 more I had a car I drove clear to Puerto Vallarta, Mexico and back and several thousands of miles more than just that.
• 1985 VW Golf Diesel for $600. It had a shifter problem and needed some suspension work for around $300. I drove that car 14 times to the in-law's some 600 miles away, not to mention all my other driving for 7 years, then I finally decided to upgrade, not because the car had issues. I just wanted something a bit more confortable with things like A/C.
• 2006 Prius for $300. The car mainly has some deer damage to the front but nothing impossible. It runs very well and I hope to use this car for a long time.

Now compare that to an imaginary Leaf of those same years. At 15% loss every 6 years, a 14 year old "2006" Leaf will only have 65% of it's battery left. The 27 year old "1993" Leaf will have only 32% of it's battery left. And the 35 year old "1985" will have 12% of it's battery. (And that's being optimistic that they won't degrade more rapidly or just outright die as time goes on).

But OEM batteries go for $8,500 right now. Would you pay $8,500 on a $250 to $600 car knowing that this is a replacement item that should be replaced every 12 years? How cheap would a battery have to be to make it worthwhile for a used car buyer?

But you know what could mitigate all of this?

BETTER COOLING! There's plenty of data showing that Leaf (and other EV) battery degredation is directly connected to heat. Make bigger and better cooling systems and the battery will last longer.

ICEV engines are lasting much longer than ever. There are now 400,000 and even +500,000 mile clubs for cars with the original engine. And if you rebuild the engine it's going to be some $2,000 to $3,000 at most and last you another 300,000 or 400,000 miles or so. That's what battery replacement should be like and cost, $2,000 every 30 years or so. But a $8,500 battery every 12 years doesn't sound anywhere close to that.

[JulianEdgar]

Originally Posted by aerohead

Depending on driving velocity, no doubt, some BEVs will demonstrate lower cooling drag than 1.4% of overall drag.

Well, where is your citation to support that? There aren’t any! I go on published evidence, not guesswork.

[JulianEdgar]

Originally Posted by ME_Andy

I suspect the initial, shocking claims were made in an attempt to stir up controversy -- and it worked!

Not at all. I saw a statement often made here that didn’t seem to be supported by the facts, and drew people’s attention to that.

No one has been able to show any data on BEV cooling drag as a percentage of total drag that rebuts what I wrote in the first post.

Instead, there’s been a few good posts.... a huge amount of irrelevant and / or misinformation posted. Par for the course here.

[freebeard]

Originally Posted by ME_Andy

I suspect the initial, shocking claims were made in an attempt to stir up controversy -- and it worked!

I'm not going to post the definition of controversy, but I recommend you look it up.

Why haven't you posted on Youtube in the last month?

[JulianEdgar]

Originally Posted by freebeard

Why haven't you posted on Youtube in the last month?

Because I have been doing other things.

[freebeard]

The new shop is a better use of your time.

[AeroMcAeroFace]

Originally Posted by aerohead

Depending on driving velocity, no doubt, some BEVs will demonstrate lower cooling drag than 1.4% of overall drag.

Exactly, at 1mph, almost all drag is rolling resistance. This statement is of no use.

"No one has been able to show any data on BEV cooling drag as a percentage of total drag that rebuts what I wrote in the first post."

Julian, while I agree, it may be worth specifying aerodynamic drag, because total drag is both linear (rolling resistance) and exponential (aerodynamic).

aerohead is correct when he writes that at some velocity 1.4% of total drag is cooling, however that includes rolling resistance. Ignoring rolling resistance is essential to get correct numbers.

[JulianEdgar]

Originally Posted by AeroMcAeroFace

Exactly, at 1mph, almost all drag is rolling resistance. This statement is of no use.

"No one has been able to show any data on BEV cooling drag as a percentage of total drag that rebuts what I wrote in the first post."

Julian, while I agree, it may be worth specifying aerodynamic drag, because total drag is both linear (rolling resistance) and exponential (aerodynamic).

aerohead is correct when he writes that at some velocity 1.4% of total drag is cooling, however that includes rolling resistance. Ignoring rolling resistance is essential to get correct numbers.

Yeah, I always underestimate some people’s ability to muddy the water. I have always been talking about cooling drag as a percentage of total aerodynamic drag.

[aerohead]

Originally Posted by Isaac Zachary

Did you buy it new or used?
If used, is that 15% of the total or 15% of what it had?
Is this car garaged?
What kind of driving is done with it, how many miles a year, how many long trips, etc.?

You see, to a new owner that might not seem like a bad thing at all. In 12 years your car will finally be needing another battery (unless used for very short trips) and to most people by the time that happens they'll have moved on or it becomes a second car for those short trips here and there.

But what about the used car market? I know I don't represent every used car buyer out there, but I think my experience is somewhat normal. Here are some cars I've bought and used quite extensively:

• 1993 Mazda 323 for $250. The head was warped and needed a radiator. For about $500 more I had a car I drove clear to Puerto Vallarta, Mexico and back and several thousands of miles more than just that.
• 1985 VW Golf Diesel for $600. It had a shifter problem and needed some suspension work for around $300. I drove that car 14 times to the in-law's some 600 miles away, not to mention all my other driving for 7 years, then I finally decided to upgrade, not because the car had issues. I just wanted something a bit more confortable with things like A/C.
• 2006 Prius for $300. The car mainly has some deer damage to the front but nothing impossible. It runs very well and I hope to use this car for a long time.

Now compare that to an imaginary Leaf of those same years. At 15% loss every 6 years, a 14 year old "2006" Leaf will only have 65% of it's battery left. The 27 year old "1993" Leaf will have only 32% of it's battery left. And the 35 year old "1985" will have 12% of it's battery. (And that's being optimistic that they won't degrade more rapidly or just outright die as time goes on).

But OEM batteries go for $8,500 right now. Would you pay $8,500 on a $250 to $600 car knowing that this is a replacement item that should be replaced every 12 years? How cheap would a battery have to be to make it worthwhile for a used car buyer?

But you know what could mitigate all of this?

BETTER COOLING! There's plenty of data showing that Leaf (and other EV) battery degredation is directly connected to heat. Make bigger and better cooling systems and the battery will last longer.

ICEV engines are lasting much longer than ever. There are now 400,000 and even +500,000 mile clubs for cars with the original engine. And if you rebuild the engine it's going to be some $2,000 to $3,000 at most and last you another 300,000 or 400,000 miles or so. That's what battery replacement should be like and cost, $2,000 every 30 years or so. But a $8,500 battery every 12 years doesn't sound anywhere close to that.

A neighbor has been tracking Tesla. Evidently, when one uses a Tesla Supercharger, telemetry broadcasts the charge data to Tesla Motors' engineering.
From what Tesla is observing, it appears that their battery packs will provide a million-mile service life.
For other products I have no such data.