Home » Every Car Dealer Selling Used EVs Should Provide Information On Battery Health

Every Car Dealer Selling Used EVs Should Provide Information On Battery Health

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I just wasted time. Lots of time. I drove three hours to look at a BMW i3, but the car wasn’t fully charged, and I wasn’t able to drive it long enough to understand the battery range. So I found a cheap motel (whose water didn’t working, incidentally) so that the dealer could put the vehicle on a charge and I could drive it the next morning, topped up. Even then, I didn’t have enough information; the test drive was short, the dealership hadn’t done a battery health test, and on top of that, I never even heard the internal combustion engine “range extender” cut on. Trying to buy a car without this critical information feels borderline impossible. This needs to change.

To be clear, the folks at the BMW of Vista dealership I visited were nice and respectful — that wasn’t the issue. The issue was that when I asked “What shape is the battery in?” not only could the salesperson not give me an answer, but the car had apparently not had the battery checked (it had arrived recently, I’m told). When I asked the team to test the battery for me, the salesperson made that seem like a major ask, saying someone might buy the car out from underneath me if I wait until the battery test is complete.

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This just doesn’t seem like how used-EV shopping should work. A dealer should insist on providing a customer with critical information like this; a car’s value is so tightly tied to its battery health that, to forego providing information to the customer is essentially making it impossible for them to make a truly informed decision.

You could argue that the same is true of an internal combustion engine’s health, but there are tests any typical independent mechanic can do to check the engine’s major bits (a compression test, a leak down test, an oil pressure test). Testing a battery isn’t necessarily that straightforward for an independent shop, but it is straightforward for a dealership with the tools. Plus, an engine rebuild/replacement is nowhere near as pricey as a battery replacement. Perhaps as important: We’re at a weird moment in history right now; people are concerned about the EV transition, and that fear of the unknown means issues like battery degradation/battery health transparency are going to be key to making people feel comfortable in making the switch.

This problem is most important for older cars, especially those that are slowly spreading into the budgets of lower income Americans. Just because not everyone can buy a new car doesn’t mean they should have to be in the dark about the vehicle’s condition, particularly the condition of the battery, which can be tested relatively simply. Here’s what BMW of Vista’s service adviser showed me as an example of what an i3 battery health report would look like:

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That percentage figure should have been on the listing for the car I was looking at, it should have been in the service records, and the salesperson should have had that ready to go as soon as I arrived. I need to know what I’m buying.

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Look how beautiful the car is; the interior is a masterpiece. I want this machine. But upon setting off on my test drive, I saw a range of 48 miles:

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That’s not a lot of miles. Of course, this display isn’t really accurate, according to i3 owners, which is why that battery charge/discharge test that spits out the remaining capacity is so important.

We’re still at an early phase of EV sales, but especially as used, higher-mileage ones become available, we’re going to need to find a way to help people feel at ease buying a machine so that they’re not worried it will be a valueless paperweight in just a few years.

My friend Kevin Williams has had similar issues shopping for a 2018 i3. Check out that article he wrote for Road & Track.

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92 Responses

  1. To me it is liks saying all ICE car sold at dealershipa should have oil samples sent to Blackstone Labs and reports came back and studied before purchasing. Good idea but is it really realistic for our current sales environment? For EVs there are solutions out there (even if you suspect EV”s BME is out of calibration/ faulty). The advantage is BME give a lot of data quicker and at a higher resolution down to the cell level than oil analysis and potentially have a larger useful sample size of cars with cloud technologly; how many ICE cars on the road really have their fluid lab analysised?

    1. That comparison is way off, testing the battery is much simpler, the i3 has a diagnostic tool (and even more extensive testing could probably be done in-house). All they’d have to do is run the tool after doing a full charge, and the diagnostic takes a couple minutes, mostly spent navigating the hidden menu where you access the battery diagnostic tool. Definitely something that any dealer could do when an i3 is added to the inventory.


  2. “You could argue that the same is true of an internal combustion engine’s health, but there are tests any typical independent mechanic can do to check the engine’s major bits (a compression test, a leak down test, an oil pressure test).”

    I don’t know if things are different in the US but here in the UK a dealer (or a private seller for that matter) would laugh in your face if you asked to do a compression test on a car they’re selling.

    1. A dealer in the US would also laugh. However, a good dealer over here will allow you to take a car in for a pre-purchase inspection (PPI). This is where they let you take the car to a mechanic of your choosing. Now finding a mechanic that will do a compression test on a modern transverse V6 with almost inaccessible plugs in the rear cylinder bank won’t be easy, but for a 40 y.o. Jeep where the plugs pop up and say “Hi!” whenever you open the hood, that is possible.

  3. > Look how beautiful the car is; the interior is a masterpiece.

    Sorry David, that interior may be pretty but it’s gross. A newer i3 isn’t supposed to look like your Jeeps.

    Also: uninformed car salesman makes up imaginary obstacles and competitive buyers to sell you the car quickly. What are the odds!

      1. For those who are interested in battery degradation.. check out Bjorn Nyland’s channel. he has some good insights on used EV batteries degradation.. he lives in Norway where it is harsher on batteries.. it is interesting it seems the Germans (VW / BMW) seems to do better than the Hyundai and Leaf when it comes to chemistry and longevity.

        1. Is Norway harsher on batteries? I thought it was generally heat that killed them, hence the air-cooled Leaf batteries dying prematurely in southern states.

          1. Yeah, I thought the same thing – which is why my dad always stored his extra power tool rechargeables in the shop fridge, so they wouldn’t overheat in an un-air conditioned tin shed.

          2. Cold is bad for them as well. In particular, charging a lithium battery below about freezing (depending on the chemistry and charge speed) will cause permanent damage via lithium plating. But I think basically every car on the market warms the battery up above that threshold and/or charges slower when it’s colder. Maybe extreme cold’s just harsher in practice because it means more discharge per mile to run heat and condition the battery, which means more cycles overall.

  4. If you are willing to make the trip through the cajon pass, I willing to teach youhow to use an obII dongle and a smartphone to check on battery SOH. I have an EV that you might be interested in. A hyundai ioniq 2018 that needs a repair that i would be willing to let go for about 15,000. 28kwhr battery thats regularly gets 90 miles to the charge.

  5. I really hope David sees this. Here is how you can access the BMW i3’s own assessment of its battery health (which is called “Batt.Kapa.Max” and will all be in German) —

    Push and hold the trip odometer button on lower left side of instrument display.

    Scroll to “Unlock”

    Enter code (sum of last 5 of VIN)

    Scroll to battery

    It’ll give you all kinds of info including “ladung” and “anzeige” 🙂

    I totally agree that this stuff shouldn’t be so hard to find, but the good news is the i3 makes it findable. I loved my 2018 i3 and regret selling it!! Good luck!

    1. Luckily I believe David speaks German. I’m a little surprised he didn’t find this procedure himself before going to look at a used EV, but then most of his past vehicles didn’t have computers so I can understand him not knowing that many modern cars have secret diagnostic screens. 😉

    1. That’s why… it is? The i3 is able to do a battery check, there’s a diagnostic tool in the OS (it’s in a hidden menu but it took me seconds to find a 4 minute video explaining the whole process. Most of it is just navigating menus and action button press+hold). Only catch is the battery should be fully charged first, but it still seems like a fairly simple thing for dealerships. An i3 is added to the inventory; first thing, top up the battery, and once that’s done, run the diagnostic tool, note down the figures and get it on the lot with all that info right there on the window sticker.


      Although now that I think of it… yeah, dealerships would probably do this before acquiring the car, and show the owner tampered figures so they could get a better deal; and the window sticker figures would also be slightly inflated to justify a higher price… Maybe it’s up to prospective buyers to request they do this simple process when shopping for a car. The process is so simple that a dealership refusing to do it would be a major red flag anyway. Battery not topped up? No problem, I’ll come by tomorrow. Still unwilling to do it? That’s how you know you want nothing to do with that car and dealership.

  6. all of this is testament to the wisdom of DT’s decision to go electric – to discover issues like this from jumping into this emerging market. looking forward to future revelations.

  7. “When I asked the team to test the battery for me, the salesperson made that seem like a major ask, saying someone might buy the car out from underneath me if I wait until the battery test is complete.”

    BS. Given their 5 day, 250 mile return policy you could have just bought it and had them run the test before you took it off the lot. If you don’t like the results you hand it right back to them. This was pure scummy salesman behavior.

  8. As someone who was an early EV adopter ( Chevy Volt ) I would be cautious looking at any older EV. As much as the manufactures want to claim, the batteries have a finite lifetime and when they do go- which they will- then you’re looking at a minimum of at least $5,000 for a rebuilt battery- which I have heard from others are not nearly as good as the originals.

  9. The car is cheap, has 135,000 miles on it and half its maximum range when new. David has already spent hours on it and hasn’t even purchased it yet. I have all the information I need to make a purchase decision, if I were the buyer.

    Hopefully David makes the right decision and winds up with a reliable car that improves his social life, if that is his goal.

  10. Excellent points! Now that you’re a California resident, I think you should request your state AND national legislative representatives consider legislation requiring this, something along the lines of the Monroney sticker. BTW, I have insisted dealers do compression tests on older used cars that I was considering buying (at no cost) and they had no problem doing so.

  11. “A dealer should insist on providing a customer with critical information like this; ”

    ROFLOL… as if.

    In my direct experience, most dealers don’t know jack shit about the used cars they sell AND they put effort into staying ignorant about any issues as one of the ways they avoid liability and accountability AND will routinely tell you BS like “they’re all like that” when you point out a problem (such as the Ford Focus I tested that was excessively noisy because the hydraulic engine mounts were shot… and the used car dealer tried to BS me into believing that all Ford Focii were like that).

    1. ” and the used car dealer tried to BS me into believing that all Ford Focii were like that).”

      Well they could be but that isn’t exactly a selling point.

    2. Years ago, I learned to ask all questions as neutrally as possible. Some salespeople will tell the truth or at least spin and dodge a bit, but some will just do their best to tell you what you want to hear even if it’s a bald-faced lie. As far as they’re concerned, it’s a win to just get you in the door and maybe they can talk you into buying what you don’t want. Don’t ask if it has the Max Trailering pack – ask what the GVWR is or for a photo of the sticker. Don’t ask if it’s a manual, ask whether it’s a manual or an automatic.

  12. Battery performance tests and health status should be built into the infotainment system or trip computer and available for consumers. It should not require expensive dealership level diagnostic equipment. If my iPhone can tell me about battery health, why can’t an EV?

  13. Whenever a salesperson tells me that the car will sell before they can help answer questions about it, I walk away. Not many sales people or their supervisors know much about EVs and they are learning the hard stuff at the same time we are.

  14. I’ve never seen a dealer give compression test or leakdown test results on a used car. If you want that you get a pre purchase inspection. It’s always been the buyers responsibility to check out the condition of a used car, and that’s not going to change with EV’s.

    1. Yeah, exactly. And the dealer is right, they can sell the car to anyone who might not know to ask that sort of thing.

      What we *should* be asking is for it to be easier for independent shops to test battery health. Which leads us right back to Right to Repair…

  15. If customers aren’t asking, they aren’t going to provide it. And I’d guess most customers don’t know enough to wonder about the battery condition, just like they don’t ask too many questions about a used ICE car.

    Tires look good, paint is shiny, it doesn’t smell inside. Looks good to 90% of buyers.

    1. That was my first thought as well. Most buyers probably just don’t know enough to ask about it. I certainly wasn’t aware that there was a report available to quantitatively describe the state of the battery.

      But the subject should be on the mind of anyone in the market for a used EV. We’ve all used devices powered by rechargeable batteries for years — decades even. We’ve seen battery degradation in cell phones, laptop computers, even our remote controlled cars when we were little kids. When it’s seen as a minor miracle that a 3-year-old cell phone can still be used today, it’s definitely worth asking what the state of the battery is on a 9-year-old electric car.

  16. David, you are correct. I bought a USED Kia Soul EV and the dealer was terrible. No battery state of health, they tried to sell me an extended warranty which was fun: I knew it was fluff and asked if the battery was covered. They said “yeah everything”. I had them call the extended warranty line, and that person said “yeah the battery is covered” I replied, the EV battery or the 12v battery. They did not cover an EV battery.

    I knew that Kia would warranty the battery and lucky I knew that because it just recently bricked itself. Kia took months to build a fresh pack, I got it back and drove home and then it wouldn’t take a charge. It’s back at the dealer. We shall see what happens next.

  17. This is annoying. I feel like any dealership selling a used EV needs to 100% have a battery health tied to a vehicle sale. No battery test, no sale, unless they offer a multiple year unlimited mile warranty on them.

    1. I think the dealer probably did do the diagnostic testing when they were deciding how to price it. The fact that it was the cheapest i3 around and the dealer is hemming and hawing about providing the battery data are not a coincidence IMO.

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