I have been weighing the pros and cons of a future EV purchase, not in the immediate future, but maybe in the next few years. But it would probably need to be a fairly low (like under $10,000) budget. And there are some questions that I have where I can't seem to get a straight answer. Perhaps there aren't straight answers to be had; if nobody knows at all, that would also be worth knowing.
First, just how long do the batteries last? Some EV advocate sites have been claiming "Don't worry, the batteries should last 10 to 12 years!" Needless to say, with both my daily driver and my wife's coming up on 12 years, I read that as "Worry like crazy!" Does anyone have better numbers, ideally with a link to data?
Second, I've heard one report of a Ford Focus EV that had its battery pack wear out and the electronics simply refused to operate even though the battery could still be capable of driving the car with diminished range. How many cars have some sort of hard cut-off programmed in, where X% loss of battery capacity means it can't be driven? And if a car has this programmed in, what does it take to override this? Some sort of factory diagnostic tool, or Ghidra, major league coding skills, and a massive disregard for copyright laws?
Third, what EVs lend themselves to home battery swaps, and which ones don't? The Tesla Model 3 supposedly has them somehow built into the floor pan and difficult to remove.
Fourth, some sites claim that it's possible to repair EV battery packs by locating which battery cells are dead and just replacing the dead ones. How much does this extend a battery pack's lifespan, and what tools are needed to test the individual cells?
In reply to MadScientistMatt :
I don't know any answers 100%.
But for #3, do you mean getting a factory battery pack and replacing it? Or some kind of DIY battery? Although, I doubt either is going to be realistic- not sure that companies will want to take the risk of DIY battery swaps. Yea, I know they will let you do it all day long with a gas engine and all of that. But this isn't the same thing, and different training will be needed to deal with the battery.
For #4, I'm sure that's possible, if you can actually identify which cell is done. But I've tried some DIY battery building- welding cells together and whatnot. Not easy. I'd study this one a lot before you pulled the trigger on an EV that has range issues.
One thing that is common among 2-4 is getting into the car's EV software (controller, BMS, etc). Have you seen that people are reliably doing that? Some of the batteries I played with came with BMS's that had not been hacked, so it took a lot of physical work to take them apart.
On the other issues:
MadScientistMatt said:
Second, I've heard one report of a Ford Focus EV that had its battery pack wear out and the electronics simply refused to operate even though the battery could still be capable of driving the car with diminished range. How many cars have some sort of hard cut-off programmed in, where X% loss of battery capacity means it can't be driven? And if a car has this programmed in, what does it take to override this? Some sort of factory diagnostic tool, or Ghidra, major league coding skills, and a massive disregard for copyright laws?
Depends on the car, factory diagnostic tool is the best-case scenario, but Ghidra + l33t coding skills + wanton disregard for the sacred copyright laws might be needed.
MadScientistMatt said:
Third, what EVs lend themselves to home battery swaps, and which ones don't? The Tesla Model 3 supposedly has them somehow built into the floor pan and difficult to remove.
I know the Leaf and Tesla S have a pack that can be dropped out of the bottom of the car, and older Priuses have them as a box below the seats. Building the pack into the car is unusual from what I've seen so far, most EVs have a pack that unbolts from the floor.
MadScientistMatt said:
Fourth, some sites claim that it's possible to repair EV battery packs by locating which battery cells are dead and just replacing the dead ones. How much does this extend a battery pack's lifespan, and what tools are needed to test the individual cells?
This is true, it extends the pack's lifespan by the difference between when that one cell died and the average life of the remaining cells I suppose...or maybe to the life of the next outlier cell to die early. To test an individual cell you'd just need an ordinary multimeter, but a dedicated chemistry-specific battery tester you can get from AliExpress for $20 might be helpful. You'll also need spot-welding tools to reassemble a battery module with replacement cell, again they can be had for lunch money.
The Leaf and Volt debuted in 2011 and every other mass market EV is even younger--that's just not that long ago. EV tech is so different between manufacturers, and the changes in battery chemistry, pack construction, and controller programming from generation to generation of EVs make it hard to draw meaningful conclusions. Only Tesla has a large enough pool of consistent data to draw from--and those conclusions are not necessarily representative of EVs outside of Tesla.
Having just searched for and purchased a used EV in that price range, I'd say that cars currently under $10K are going to be first generation tech that is seriously compromised in terms of available range. These cars really only make sense for a niche set of use cases.
We paid a little more ($12K including taxes and registration) to get a second-generation Nissan Leaf. Its a great car and I enjoy running errands in it--but its real-world range of about 130 miles just isn't enough for most people.
Right now you need to move up to the $15,00+ range to get a Bolt or early Tesla in order to have over 200 miles of range. However if you don't plan to purchase for several more years, I bet that the used EV landscape at that time will have whole host of better and cheaper options.
I think only the Gigapress Teslas have structural batteries. Not sure if they're replaceable or not, but they are for the earlier (much more common) cars. Tesla publishes their service manuals if you want to read up on the process.
Other than the Leaf (which does not use water cooling), EV battery lifespan looks to be on par with ICE lifespan at least. I suspect we'll also see the growth of refurbished battery packs like we see remanufactured engines.
The current incentives for buying EVs favor leasing. So in a couple of years, there will be a lot coming off lease and hitting the used lots.
