Thanks to Brad L. For this question and prompt for this blog post.
I see variations of this topic online posted mostly in conjunction with articles that are clearly anti-EV in nature. In these articles, one will find statements about how batteries or electric motors won’t last and that they are very expensive to replace, resulting in conclusions that EVs are too expensive to own and may not last as long as an ICE (Internal Combustion Engine) vehicle.
Let’s first look at this at a macro level first and then break down the data a bit.
The first interesting point is that I believe people think cars last much longer than the actually do. The average car in the US is scrapped by about 175,000 miles (150,000 in Europe… better made in US?). It is interesting that data shows that most ICE transmissions only last about 175,000 miles, which tells me that once a transmission goes on an old car, people don’t spend the money on them to put a new or rebuilt transmition in them and they scrap them. Only 1.2% of all cars made ever see 200,000 miles. Only 0.03% of the cars in the US currently have over 300,000 miles on them. Based on this data, I am going to state right now that any EV that exceeds a 200,000 mile design life before major components need to be replaced is as good as todays average ICE vehicles.
Geek Note: Transmissions fail due to metal fatigue. The gear surfaces over time start to get pitted, and then the metal fails. Every transmission will eventually fail. The speed at which this happens is a function of the force and number of rotations (miles driven). In order to get reasonably sized transmissions, the engineers have to balance longevity over size. Larger transmissions give larger gears which gives larger surface areas which gives lower forces internally and longer life. But larger gears are heavier and result in lower fuel economy. EV motors generally have at least one gear step down, but size of these gears are not as critical, and as such, they can be wider to distribute the forces in them to reduce fatigue.
Moving parts comparison:
While I am on the topic of transmissions, let’s explore the topic of moving parts.
Average EV drivetrain: 20 moving parts
Average ICE drivetrain: 2000+ moving parts
Things that move, wear out, and the more they move, the sooner they wear out depending on the design and materials used. Just think of the human body. How many people do we all know that have had hip and knee replacements?
The result is generally that an ICE vehicle needs more TLC to monitor and replace all of these moving parts. On the plus side, since these parts wear out so frequently, they are generally more readily available and cheaper to replace. ICE automakers seem to have determined that the sweet spot is somewhere in the 175k miles for their drivetrain designs, so let’s explore an EV’s drivetrain... Motors and Batteries. (I’ll also assume that all other components between an ICE and EV are similar enough to be considered to have similar life… things like HVAC components, suspension, electrical systems, etc.)
Susan and I have owned 11 different vehicles since we have been married, and 3 of them had major transmission issues before 100k miles of ownership (2 in under 60k miles). We cut our losses and got rid of them all earlier than we had planned. We generally keep a vehicle through 100k miles before trading them in or passing them on to our kids in recent years. Our oldest car is a 2012 Sonata Hybrid with 120,000 miles (which is in great shape and is for sale if anyone is interested).
EV Battery Life Analysis
Over the last decade or more, I have generally seen that a typical rechargeable battery like the ones we have in our cell phones and laptops are good for 300-500 charging cycles. I personally get about 2-3 years out of a cell phone before I start to notice significant reduced battery capacity and by about 5 years, it is time to replace the battery or the entire phone. The early EV batteries (like a Nissan Leaf) were generally of this design, but the auto industry quickly identified that this was not going to be adequate. Today’s modern EV batteries, depending on the chemical composition of an EV battery, are capable of 1500-2000 or more cycles. Depending upon the different sources I was able to find, some claim they are already at 3000-4000+ cycles. In Tesla’s yearly report, they state their current generation of batteries are expected to exceed over 4000 cycles which they also claim could easily last over 1M miles.
Also note that many people erroneously conclude that EV batteries become useless after this many cycles, which isn’t true at all. The industry generally uses the threshold of 80% of the original capability as a definition for a battery’s End Of Life (EOL) point. The Tesla Model S/X battery degradation chart below shows their fleet data with their older battery formalizations. Note that the majority of the battery degradation occurs in the first year or two of ownership then pretty much flattens out to 1-3% of degradation for the rest of the ownership experience. (I was looking at my old posts and see I haven’t covered my battery degradation…but mine looks similar to the plot below so far) In fact, there are companies that are looking to take the battery packs out of scrapped EVs and repackaging those packs for the purpose of power storage (home or business).
Lets do some math based on 2000 cycles and my Model Y so far.
I am averaging 400 wh/mile through the first year of ownership (~300 wh goes toward driving, and ~100 wh goes toward other things), roughtly 20,000 miles driven. That is equivalent to roughly 8000 kwh of total energy put into and pulled out of my car’s battery which has a capacity of about 75 kwh of usable storage. That is the equivalent of 110 full charging cycles of the battery (I am not a battery expert, so I think this is how this is computed). If my usage continues on this pace, I will hit 2000 cycles after about 18 years of driving. That would equate to over 360,000 miles of driving. 4000 cycles would give me over 700,000 miles of driving. This is at least double if not 4x the life of an average car. I am also confident that this is way longer than the body and interior will last.
It is for this reason that EVs with smaller batteries will have a much short lifespan. For example, I can drive 250 miles with a complete charge (one cycle) of my Model Y battery. The first generation of a Nissan Leaf had about 80 miles of range, maybe about 60-70 highway miles. That same 250 miles would require 4 cycles of the Nissan Leaf Battery. For this reason, the early Leaf models are expected to only get about 100,000 to 150,000 miles of life.
Electric Motors
There is very little information about this out there on the internet. The truth is that no one really knows right now because EVs are so new. Tesla has released reports that they have tested their Model 3/Y motors in house to well over 1M miles equivalent. Given that most ICE engines with 100x the number of moving parts are good for about 200k, it is likely safe to say that electric motors will last at least that long but probably longer.
I see very few posts about Electric Motor longevity online. The lifewire source referenced below claims gas engines and Electric motors both will likely last more than 20 years or more. It’s the transmissions in ICE vehicles that seem to be the biggest life limiting factor and are generally expected to last about 15 years after normal driving. EVs do not have transmissions as I covered above.
Replacement Costs
There is no doubt that currently, replacing the battery and motors of an EV is an expensive proposition. 2-3 times the cost of replacing the engine or transmission on an ICE vehicle. Thankfully, based on the analysis above, this is an unlikely event that an EV owner will ever have to deal with. Also note that if they do, the owners have likely already saved several thousands of dollars over the life of the vehicles in other maintenance costs (oil changes, belts, brakes, rotors, etc) that an EV owner will not have. I also believe that in the next 10 years, a new industry of battery reconstruction, battery replacement, electric motor repair and replacement will be common and the prices of repair and replacement of an EVs drivetrain will come down. If anything, we are going to start to see EVs that were in accidents get scrapped (totaled by insurance companies) whose motors are fine or whose batteries are fine (although I might be hesitant to take on a battery pack that was in an accident).
The largest risk an EV owner faces honestly is puncturing a battery pack from driving in off-road conditions or hitting something on the highway. In this case, auto insurance should cover the cost of the repair.
There
Examples of Longest Surviving Teslas
There is a German Tesla Model S (it is a 2012 or 2013) that now has over 1M miles driven on it. The battery pack has been replaced twice and the motor 8 times. Tesla motors have gotten significantly better since their early models and I have no idea what driving on the Autobahn at 160 miles/hour does to a motor. The newest Model S has a totally new design with carbon fiber wrapping to prevent thermal expansion.
Tesloop is the owner of some of the worlds longest running Teslas. They had a Model X (2016?) that hit 400k miles in early 2020. The main battery lasted until 317,000 miles. No issues with the motors.
They are also the owner of a Model S that has over 300,000 miles. At 200,000 miles, the battery management system became inaccurate. Tesla indicated they had a firmware update that would better, more accurately estimate the battery percentage for older batteries. Otherwise, the battery was fine. For some reason, Tesla decided to replace the battery anyway for them.
Summary
Based on the information I have read, and some of the basic analysis I have done, I am confident in saying that most EVs produced today will go as many or more miles without significant component issues as compared to their ICE counterparts. But of course, this has to be taken with a grain of salt as there are currently over 40 different EVs on the market here in the US, and each one is going to have different lifespans based on the makers design approach just like different ICE vehicles (any remember the Yugo?). For example, some EVs, even todays model, still have smaller battery packs or do not have active battery temperature management to keep prices down. Studies have shown that the batteries in these models generally have shorter lifespans than EVs with active battery temperature management, particularly ones that are liquid cooled like in a Tesla and BMW.
I think that today’s EVs are designed to last longer than 300,000 miles and I also think that ICE drivetrains continue to get better as well. In fact, I think with most cars purchased these days, the drivetrains will outlast the body and interiors of these vehicles. Carpeting, linings, and seats will break down from constant sun and heat in the cars faster than the rest of the cars for sure. Paint will get scratched and panels will get dented.
When our kids were younger, knowing that we had a high probability of our cars starting was a must, so we generally replaced them as they were just over 100,000 miles. Now that Susan and I commute together on most days, if one car doesn’t work, we would just try the other one (or the third one…did I mention it is for sale?). So we’ll probably attempt to keep the cars we currently own for a much longer time. 200,000 miles might be our new threshold, but we’ll see. My current plan is to replace my Model Y with a Tesla CyberTruck. Based on current news and the number of orders before me, my Model Y might easily have 200,000 miles on it before I get my hands on a CyberTruck… ooofffff.
Other Sources: