Used EV battery health: what's actually the reliable way to check?

I bought my 5N sight unseen from 2,000 miles away and basically trusted the dealer's report. Worked out fine but I wouldn't call that a strategy lol

On the Model 3 the range number isn't based on recent driving. It shows rated miles, so if you charge to 100% and compare that to the original EPA range, you get a fairly good rough idea of the pack's health. That doesn't work on the Ioniq 5, which uses the guess-o-meter.

Is there a LeafSpy-type app that works on a Bolt, or is it the same deal as Hyundai where you have to get the dealer to run it? I'm looking at a 2022 and I'd like to see the actual battery numbers, not just whether the recall swap was done.

Related question since I'm planning to bring a dongle and LeafSpy to look at a 2017 Leaf: if the SOH comes back decent, does mileage still matter much on an EV? Or is it not the same red flag it would be on a gas car?

Just went through this buying from NI. Honestly the best thing I did was get an independent battery certificate. The dealer I bought from (iGen in Magherafelt) supplied an AVILOO report, and I still hired my own inspector on top of that, Andy McNeice, £220. He went into service mode for hidden fault codes, checked underbody and suspension, and drove it. The dealers who didn't want an inspector or said they 'don't do battery checks' were exactly the ones I walked away from. One told me there was no need because he was AA approved. If a seller pushes back on an independent check, that tells you plenty on its own. Inspector prices I got varied a lot, roughly £150 to £300 / €250, so shop around.

Following this. I'm looking at a 2021 MG ZS EV, 51k km, private sale. Seller says 280-290 km at 80 km/h but I'm not sure how much to trust that. Planning to ask for an MG service centre SOH report before I commit. Does anyone know if MG dealers will actually print one for a non-owner, or does the seller have to book it?

Following because I'm in the same spot. My experience so far is that if you're buying from a dealer you basically won't get a number. I've asked every single one I've talked to for an SOH % and it's been a flat no every time. A couple acted like I'd asked for the previous owner's banking info. What I keep reading is that a ~$100 bluetooth scanner plus an app will give it to you. I just haven't been anywhere that would let me plug it in yet.

What scanner/app combo works for a Bolt? I'm looking at buying one out of state and shipping it, so I'll probably have to get whoever does the PPI to do it, but I'd at least like to tell them what to use. Most of the shops near the listings I've found don't seem to touch EVs. I'm coming off a 2014 Leaf at about 3/4 of its original capacity so I'm not taking anyone's word on this one.

Following this as mine's a similar question but about mileage. Most of the Teslas and Polestars I can afford at 3-4 years old have 60-80k miles on them. On a diesel I wouldn't think twice about that. Is it a lot for an EV battery or am I overthinking it? I'd be financing over 4 years so I really don't want the battery going halfway through.

The thing that tripped me up when I was shopping last year was trusting "it charges fine" from sellers. That tells you nothing. A pack can charge totally normally and be sitting around 70%. What I ended up doing was comparing the range it shows at 100% to what the car was rated for, at least as a rough first filter. Not perfect but it weeded out a couple listings fast.

So for the Ioniq 5 it's basically the dealer's health check or nothing? I'd heard those packs hold up better than people expect, so I was kind of assuming a 2024 would be fine. Sounds like I should still ask for the actual number before getting too excited about a deal.

Is there a LeafSpy-type app for the Bolt? The one I'm looking at is a 2017 on Carvana, so there's no dealer to run a health check, and the listing really only gives the mileage.

Similar boat here, except mine's a 2017 Leaf and the listing is pretty much just the mileage too. I'm planning to bring an OBD dongle and LeafSpy. But does mileage even matter much on an EV the way it does on a gas car? Or if the SOH comes back decent, is the odometer mostly irrelevant?

Honestly the mileage feels like the smaller question to me. The one I'm looking at only has 24k on it, but it turns out the battery recall is still open. I can't tell if that's a big red flag or if it just means a new pack eventually. Does anyone know how long people are waiting on replacements these days?

How did you find out it's still open? Did you just put the VIN in somewhere online, or did a dealer have to tell you? The Bolt I'm looking at doesn't say either way.

So does 12 bars not tell you much either? The 2021 Leaf I'm looking at shows all 12 and the dealer is kind of leaning on that. I was already planning to grab a dongle and LeafSpy before signing anything, sounds like I definitely should.

Not an Hx number, but for reference the 2015 I bought showed 12 bars and LeafSpy gave 87% SOH at 67k miles. So bars really don't separate a decent one from a tired one. It took about two minutes at the seller's, so you won't be standing there long.

I just put the VIN in on the Chevrolet site's recall lookup and it lists any open recalls for that car. It's free and takes a minute, so you don't need the dealer for it. Mine came back with nothing incomplete. Do you know if that also tells you whether the battery replacement was already done, or is that a separate thing?

Thanks, I'll try the VIN lookup on mine too. The one I'm looking at shows an open battery recall. Can you just leave a Bolt parked until the replacement appointment, or does it need to be driven or kept at a certain charge in the meantime?

Useful to know. Do you have a sense of what a normal rated-range drop looks like for a 2018-2021 Model 3 at 40-80k miles? The EV lot near me lists battery health on every car and only 3 of the 12 cheapest were at 85% or better, which surprised me.

That's useful. I test drove two 2021 Model 3 RWDs with about 40K miles and neither dealer said anything about battery health, so I didn't think to do the 100% charge and compare to the EPA number. Is it reasonable to ask a dealer to charge it up for that during a test drive, or do they usually say no?

Not a Leaf, but a dealer-pulled report is how I found out about mine. A 3 year old C40 with about 8k miles came back at 89% SOH when I was expecting 92-93%. The dash looked fine, so I'd push for an actual number from somewhere, even if it costs you a service visit.

I daily a 2nd gen Leaf, and the 2nd gen shows capacity in a dash menu you scroll through with the steering wheel arrows. First gen only has the 12 bars, and a lot of used ones won't show all 12. A lot of sellers don't know to look for it, so I'd ask for a photo of that screen in the listing. I'd still go with a Bluetooth OBD-II dongle and LeafSpy over calling a service department, since it's cheap and gives you a much better picture than any bar count.

Open battery recall aside, I'd be more worried about cars that throw errors. I bought a junk 2019 40 kWh Leaf that had a "Service EV System" error. When I opened the pack, one cell block was swollen and punctured by the housing. I swapped the block myself, and the car passed inspection here in Japan. I skipped balancing, so I get about 160 km max range with a ~400 mV spread between cells.

That's the part I couldn't get on my used R1S. The dealer sent me a photo of Settings > About, which confirmed the pack and wheels but gave me no health figure. The inspection report only covered brakes, tires and general notes. Did your C40 report come with the SOH number printed on it, or did they just tell you the percentage?

Same problem here. I'm going to see a 2023 EUV with about 40k miles this weekend, and the dealer's listing doesn't say anything about battery health. I read the FAQ and searched the sub and couldn't find a way to see charge history, only SOH-type numbers. I suspect it came off a rental or fleet, so I'm wondering if a pack that was cycled 100% to 0% a lot is something to worry about. Is that worth raising in negotiation, or does a decent capacity reading make the history irrelevant?

Does the dealer check work okay in the cold? I test drove a used 2020 Kona at -16 °C and it showed about 30% with roughly 70 km left. I couldn't tell if that's just the weather or a tired pack, so I'd like a real number from the Hyundai tool before deciding.

Same trouble getting anything verifiable. The 2025 Ioniq 5 I'm looking at is at an independent lot. The dealer says the ICCU and 12V were replaced, but Hyundai has no record of it. A VIN lookup also showed it was a lemon law buyback. So a health number wouldn't even cover my main worry, since there's no powertrain warranty after purchase. Has anyone found a way to confirm a part swap like that without the Hyundai service history?

The rated-range trick is how I ended up worried about a used 2023 Standard Range I looked at. It showed 51% and 168 km at the dealer, so I figure about 340 km at full. That seems low with only 6,000 km on it. I can't tell if it's the cold or real degradation, so I'm going to ask for an actual health number before going back.

Seconding the dongle. Mine was a cheap 2018 SV and Nissan swapped in a warranty pack under two weeks after I bought it, and the bars never hinted at anything. Worth asking a Nissan service dept to check warranty coverage by VIN too, but LeafSpy first.

My 2019 Bolt is at about 150k miles and I've held off on the recall replacement so far, still on the original pack. I can't speak to wait times since I haven't booked it. If you're buying one with it still open, I'd just price that in and check what GM says for that VIN.

Can't say for sure whether a dealer can see the replacement date by VIN. I can say that both my Bolts got new packs under the recall (the 2021 at 40k miles), so a closed recall meant a real pack swap on mine, not just software. I'd still ask for the paperwork, same as you said.

I'd price the open recall in pretty hard. I had a Bolt EUV for a few months, and the recall restrictions got old fast when I was still making full payments on a car I couldn't use the way I wanted. I ended up taking the GM buyback. It was a great car for local stuff, but living with an open recall wasn't fun.

Same experience here, a real number beat the dash. I bought a 2021 Mach-E with about 103k miles, and the dealer (Recharged) ran an independent Aviloo test on it before I paid. It came back at 98%, which I never would have guessed at that mileage. Seeing a result that didn't come from Ford's own statements made me a lot more comfortable buying.

Also wondering about this, since I'm looking at a Bolt too. Is there anything like LeafSpy for them, or is the dealer the only way to get a real capacity number before buying?

Good question about whether the lookup shows the replacement. I'm looking at 2022/2023 Bolts, so I assumed the new pack was built in from the factory, but I'm not sure. Does anyone know if there are any TSBs worth asking about on those years?

Does the rated-range check work if the seller only has the car at a lower charge limit, like 80%? I'm looking at a Model Y and wondering if it's fair to ask them to charge to 100% and compare to the original EPA number for that exact trim, or if that's too much to ask of a private seller.

Does anyone know if there's a Mach-E equivalent of this? I'm test driving a used 2025 this weekend and I'm not sure whether the rated-range trick even applies to Ford, or if a Ford dealer would have to pull the battery number. Used ones near me are priced close to new, so I'd want a real figure before paying that.