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Used EV Battery Health Checks: 5 OEM-Verified Paths and What the Numbers Mean

Last verified October 27, 2026

Re-verification overdueThis guide remains available for context but is not presented as current until it is rechecked.

A used EV's battery-health display is only useful if you know how that number was produced. An older Nissan LEAF's capacity gauge and the redesigned 2026 model's capacity percentage are not interchangeable. Current manufacturer documentation shows several different workflows: a controlled test that can take most of a day, an owner-visible capacity indicator, an in-car state-of-health estimate, and a retailer-issued certificate.

This guide tracks the exact U.S. vehicle/source scope that ATC could verify. It does not treat every State of Health (SoH) percentage as the same measurement, and it does not treat a health display or third-party certificate as automatic proof that an automaker's battery-warranty threshold has been met.

Not established means the checked current source does not prove the field. It does not mean the capability does not exist.

Quick answer

Vehicle / source scope What a buyer can obtain Where / who runs it Time or prerequisites What the OEM says the result means Important limitation
Tesla Model 3 — current U.S. owner-manual scope BMS-based Battery Health evaluation; optional controlled Battery Health Test if the vehicle has the feature.1 Controls → Service → Battery Health / Battery Health Test Controlled test: AC charger ≥5 kW, battery <20%, Park, no pending software update, no active battery/thermal alert, network connection; up to 24 hours.1 Controlled test returns a percentage comparing battery energy retention with when new.1 Tesla recommends the controlled test only when there is concern about battery energy retention. During the test, climate control is disabled; do not leave occupants unattended. Do not unplug while it is running; cancel the test first if unplugging is necessary.1
2024 Nissan LEAF — original U.S. owner/warranty scope Owner-visible Li-ion Battery Capacity Level Gauge; Nissan's 2024 warranty booklet separately references 12 capacity segments.23 Select the capacity gauge in the trip-computer menu; preserve the displayed reading, model year and vehicle details. No separate controlled-test duration is established by the accessible indexed 2024 manual section. Capacity gauge concerns storage capacity; the 2024 booklet uses below nine of 12 segments for conditional capacity coverage within its term.23 Seven/eight segments are numerically below nine; nine is not. This is not an exact state-of-health percentage, expected range, battery diagnosis or automatic warranty approval.
2026 Nissan LEAF Owner-visible Battery Information capacity percentage.4 Vehicle trip-computer / information display No separate controlled-test procedure is stated for this display in the reviewed manual section. Nissan says the percentage represents the amount of charge the Li-ion battery is capable of storing and declines as capacity decreases with age/usage.4 The display also gives distance since last update. Nissan does not describe this screen as the same procedure as Tesla's controlled health test.4
Volvo EX90 — current U.S. support scope In-car Battery state of health plus distance since last estimation.5 Vehicle → Status → Battery in the center display No separate test duration or charging prerequisite is stated on the reviewed support page. Volvo defines SoH as how much energy can be stored compared with when the battery was new.5 Update cadence and warranty-decision procedure are not established by the reviewed support page.
2026 Volvo EX40 / EC40 without the center-display SoH feature Free Battery State of Health Certificate.6 Authorized Volvo retailer Bring the vehicle to an authorized Volvo retailer.6 The reviewed warranty manual establishes certificate availability, but does not describe the certificate's measurement algorithm.6 This fallback is specifically for EX40/EC40 vehicles that do not have the SoH feature in the center display.6

Is the dealer's “battery health” report about the driving battery?

Ask which battery was tested before interpreting a percentage or printout. The high-voltage traction battery powers the vehicle, while the auxiliary 12V battery runs smaller electrical systems; Hyundai's 2024 U.S. IONIQ 5 and Kia's 2026 U.S. EV6 and EV9 manuals make that distinction explicitly.789 A 12V battery load-test result is not a measurement of high-voltage pack energy retention. A current state of charge (how full the battery is) or dashboard range estimate is not automatically state of health (capacity relative to when new).

What the seller offers What the checked U.S. manufacturer evidence actually supports What to request before relying on it
Hyundai's complimentary two-minute “battery health” test Hyundai lists reserve capacity, cold-cranking amps (CCA), state of charge, open-circuit voltage and resistance and discusses vehicle starting reliability. This is not a documented high-voltage traction-pack SoH test.10 Ask whether the sheet refers to the 12V battery. If you need traction-battery condition, ask separately whether the dealer can document a model/VIN-specific high-voltage diagnostic, its output and method. Do not relabel CCA or the test's SOC as pack SoH.
Hyundai Certified Used Vehicles 173-point inspection Hyundai warns that EV, hybrid and plug-in hybrid inspection counts may differ. Its manufacturer-branded 2025 general inspection check sheet lists a battery/cable load test with “Volts” and “CCA” (item 21), plus “scan tool automatic checks” (item 2); its cover directs readers to obtain the model-specific inspection list. Neither entry by itself identifies a measured high-voltage SoH percentage.1112 Request the actual completed model-specific EV CPO check sheet, not just the general 173-point advertisement, and any separate documented traction-battery diagnostic with the vehicle's VIN, date, mileage, report type and testing method.
Kia EV6 / EV9 Certified Pre-Owned 165-point inspection Kia's current U.S. CPO page says vehicles must pass 165 points. The checked public CPO summary does not specify a customer-facing EV6/EV9 traction-battery SoH percentage, named capacity test or standardized printout. Kia's manuals distinguish the high-voltage battery and 12V battery.8913 Request the vehicle-specific inspection record and ask whether a separate high-voltage test was run, what metric it measured, and whether a dated, VIN-linked result exists. Not established does not mean Kia dealers cannot perform diagnostics.
Kia maintenance-plan “battery health monitoring” Kia names this among EV maintenance needs, but the public plan description does not specify a universal percentage algorithm, automatic buyer certificate or the same procedure for every model. A separately purchased maintenance plan is not identical to CPO qualification.14 Ask the service department which service or test was actually performed on this vehicle, which pack was examined and whether the result can be documented. Do not assume the plan guarantees a specific SoH number.

Identify the report, not merely the number

Label on the seller's evidence What it can establish What it does not establish by itself
CCA / reserve capacity / voltage / resistance Electrical condition indicators for the battery tested; Hyundai's public short test uses these terms.10 The high-voltage traction pack's remaining usable capacity.
Charge %, SOC or displayed miles of range Present charging level or a vehicle-generated driving-range indication, respectively. A maker-verified capacity-retention result or a common cross-brand degradation metric.
High-voltage capacity / SoH percentage Potentially useful only with the exact vehicle, origin and diagnostic definition: owner screen, BMS calculation, controlled test, dealer measurement or another method. The Tesla, Nissan and Volvo examples above use materially different workflows.145 Automatic equivalence across automakers, a condition diagnosis or a warranty decision.
Independent battery certificate or estimate The named provider's reported result under its own stated test/estimation method and vehicle-coverage limits.15 An automaker's certified measurement or VIN-specific warranty approval.

Buyer request: “For this VIN and odometer reading, can you show me the model-specific inspection record and any separate high-voltage traction-battery health report? Please identify the issuing tool/provider, test date, battery tested, metric and procedure, and whether the number is measured capacity, BMS-estimated SoH, charge percentage or an independent estimate.” If no documented traction-health method or result is available, record that limitation; do not convert a generic CPO badge or 12V printout into a claim about the pack.

Scope: The checked Hyundai and Kia public pages do not establish an official numeric U.S. IONIQ 5 / EV6 / EV9 pre-purchase high-voltage SoH report available to every buyer. Availability, model-year instructions and any dealer-specific diagnostic must be verified separately. These sources also do not establish what percentage is “normal,” that a particular seller did anything wrong, or whether a vehicle qualifies for warranty repair. For those separate terms, use the used-EV battery-warranty transfer guide.

Tesla Model 3: ordinary Battery Health and the optional controlled test are different

Tesla's current U.S. Model 3 manual separates two related outputs.1

The ordinary Battery Health screen gives an evaluation calculated from battery-management-system data and compares the vehicle against expected energy retention for its battery type, age and usage. The optional Battery Health Test is a controlled procedure that produces a percentage comparing energy retention with when the battery was new.1

Tesla does not present the controlled procedure as a routine test every used-car shopper should request. The current manual says Tesla recommends using the Battery Health Test only when there is a concern about high-voltage-battery energy retention.1

If that condition applies and the controlled test is run, it requires an AC connection delivering at least 5 kW, a starting battery level below 20%, Park, no pending software updates, no active battery/thermal alerts and Wi-Fi or cellular connectivity. It can take up to 24 hours and can discharge the battery below 10%, potentially as low as 0%.1

The same manual also gives material operating limits. Climate control is disabled while the test is running, and Tesla warns not to leave occupants unattended in the vehicle. Tesla says not to unplug Model 3 while the test is running; if unplugging is necessary, cancel the test first.1

For a used-vehicle inspection, start with the ordinary Battery Health evaluation if it is available. If there is a specific energy-retention concern and the seller is willing to run the optional controlled test, its charging, timing and operating requirements mean it needs to be planned in advance. Tesla also says a vehicle may not be equipped with the Battery Health Test feature, so the absence of that control should not be rewritten as a battery failure.1

2024 Nissan LEAF: capacity segments are not charge remaining or a guaranteed warranty repair

Nissan's 2024 U.S. LEAF owner manual identifies a Li-ion Battery Capacity Level Gauge in the trip-computer menu. Its purpose is to indicate the battery's remaining ability to store power; this is a different reader question from the amount of charge available for the current drive or the dashboard's estimated miles remaining.2 The checked manufacturer evidence does not establish an exact conversion from those capacity segments to a state-of-health percentage.

The original 2024 U.S. warranty booklet uses a separate, explicit 12-segment capacity threshold: conditional lithium-ion battery capacity coverage applies when the capacity indicator is below nine segments, during 96 months or 100,000 miles, whichever occurs first, subject to the booklet's exclusions. Nissan says covered repairs restore nine or more segments, not necessarily the original twelve.3 This is the booklet's capacity-coverage test, not proof that a specific used car qualifies, and not evidence that every low reading diagnoses a defective pack.

Used LEAF observation What the primary source supports What a buyer must still verify
2024 capacity gauge shows 7 or 8 of 12 segments Seven/eight is below the 2024 booklet's nine-segment capacity threshold.3 Confirm the exact model year, VIN, original in-service date, mileage, exclusions and Nissan's vehicle-specific inspection/coverage decision. Do not infer an exact SoH percentage or guaranteed miles.
2024 capacity gauge shows 9 of 12 segments Nine is not below nine; that reading alone does not demonstrate the 2024 capacity-coverage trigger.3 Investigate any separately reported symptoms or defect claims through appropriate inspection; the capacity threshold is not the sole possible battery issue.
2026 Battery Information reads a percentage This is the redesigned model's separately documented owner-visible capacity (%) and last-update-distance screen.4 Use the 2026 vehicle's own warranty terms and manufacturer evaluation; do not apply the 2024 twelve-segment rule to a percentage display.

Used-buyer evidence to request: Ask the seller to display the capacity screen in the actual car (not just available charge or estimated range), and photograph it together with the date and odometer. Record the model year, VIN, original sale/in-service date if available, charging/usage context and any dealer inspection report. If coverage matters to the purchase, request Nissan's eligibility assessment using the exact vehicle/booklet rather than making the sale conditional on a guessed percentage.

For the separate warranty and transferability question, see the used EV battery-warranty matrix. Its 2024 Nissan terms are a starting point, not a currently recertified VIN-specific warranty decision.

2026 Nissan LEAF: an owner-visible capacity number, not the same workflow

The 2026 LEAF's Battery Information screen shows Battery Capacity (%) and distance since the last update.4 Nissan says the percentage represents the amount of charge the Li-ion battery is capable of storing. As capacity decreases with age and use, the displayed percentage also decreases.4

That is directly useful during a used-vehicle inspection because it is available in the car, but the reviewed manual does not describe this display as an up-to-24-hour controlled discharge/recharge test. Record it as a Nissan capacity indicator, not as a generic standardized SoH test that can automatically be compared one-for-one with another brand's number.

Volvo EX90: state of health is in the center display

Volvo's current U.S. EX90 support documentation puts the result at Vehicle → Status → Battery.5 The page defines Battery state of health as a measure of how much energy can be stored compared with when the battery was new and also shows distance driven since the last estimation.5

The reviewed page does not give a buyer a separate test duration, charge-level prerequisite or algorithm. For a pre-purchase inspection, the defensible request is therefore simple: ask the seller to show the current Battery status/health screen and record the value, mileage and date rather than inventing a test procedure Volvo does not publish on that page.

2026 Volvo EX40 / EC40: some cars can use a free retailer certificate

Volvo's 2026 fully-electric warranty manual adds a different path for EX40 and EC40 vehicles that do not have the State of Health feature in the center display. Owners can request a Battery State of Health Certificate free of charge by bringing the vehicle to an authorized Volvo retailer.6

That distinction matters for used shopping. A missing in-car SoH display on one of those vehicles does not mean there is no manufacturer-supported health path; for the exact scope Volvo documents, the fallback is retailer-issued.

The same warranty manual separately states Volvo's high-voltage-battery warranty threshold language. A certificate or display should still be treated as a health result, while warranty eligibility should be checked against the controlling warranty terms for the exact vehicle. See ATC's used-EV battery warranty guide for that separate question.

What about an independent battery certificate?

Commercial testing can add another measurement path, but the method needs to travel with the number.

AVILOO's current U.S. materials describe its FLASH Test as a three-minute certificate using vehicle data evaluated by AVILOO's proprietary algorithms, with additional battery-management-system, sensor, cell-voltage and communication checks.15 Its current U.S. page describes ordering as business-customer only, and supported vehicles are governed by AVILOO's changing coverage database.15

Those are AVILOO's product claims, not an independent validation by ATC. More importantly, an AVILOO result should not be silently labeled the same test as Tesla's controlled Battery Health Test, Nissan's in-car capacity percentage or Volvo's SoH display/certificate. ATC's earlier reporting on AVILOO's dataset also found that the company-reported health values can vary substantially among same-model used EVs; that is one reason a model average is not a substitute for checking the actual vehicle in front of you. See ATC's AVILOO battery-health report coverage.

A practical pre-purchase battery-health checklist

  1. Identify the exact model year, battery/configuration and current software. A method shown in a current manual is not proof that every older example has the same feature.
  2. Ask for the strongest manufacturer-supported result that is appropriate for that exact car. That may be an in-car health screen, a controlled test or a retailer certificate; preserve the OEM's own conditions for when a controlled procedure is recommended.
  3. Do not turn Tesla's controlled test into a routine checklist item. Tesla recommends it only when there is concern about energy retention. If it is run, allow for the up-to-24-hour duration and starting-SOC/charger prerequisites, do not leave occupants unattended because climate control is disabled, and cancel the test before unplugging if unplugging is necessary.1
  4. Record the method with the reading. Save the date, odometer, vehicle/VIN, source screen or certificate, and whether the result was a capacity-segment gauge, passive estimate, controlled test or third-party analysis. If a dealer says “battery checked,” identify whether that was the 12V auxiliary or high-voltage traction battery and request the exact model-specific inspection report. For an older LEAF, record the capacity gauge rather than charge level or estimated miles.
  5. Do not convert one method's percentage into another method's result. The sources above describe different procedures and definitions.
  6. Check warranty separately. A health result can inform a purchase without automatically proving that the OEM's warranty degradation trigger has been crossed. Use the exact warranty booklet for the vehicle and ATC's battery-warranty transfer matrix as a starting point.

What is not verified in this first matrix

Ford, GM/Chevrolet/Cadillac, Volkswagen and additional EVs remain expansion targets. The new Hyundai and Kia document-identity comparison above establishes what their checked U.S. public CPO, 12V-test and EV maintenance descriptions do and do not say, not a verified numeric pre-purchase traction-battery SoH workflow for IONIQ 5, EV6 or EV9.

Missing from this table does not mean the brand has no service diagnostic, BMS value or dealer test. It means ATC has not yet verified the exact current consumer-facing path strongly enough for this reference.

Update policy

This is a frequently rechecked living reference. Reverify a row when an OEM changes its owner manual/software interface, releases a new model-year warranty manual, changes retailer-certificate availability, or a commercial test provider changes its procedure/vehicle coverage.

The previous September 29 review date was overdue. The five inherited source definitions and the Nissan 2024 manual/warranty scopes were checked on October 25, 2026 (with the 2024 owner's-manual PDF rendering limitation stated above). The Hyundai/Kia targeted manufacturer-document audit was performed October 27, 2026, including a visual check of Hyundai's 2025 three-page general CPO checklist. This was not an October 27 full recertification of Tesla/Nissan/Volvo/AVILOO material. The next forced whole-guide check remains November 1, 2026, or sooner if an OEM changes model-specific CPO documents, manuals/software, certificates or health-test methods.

Sources

Footnotes

  1. Tesla — Model 3 Owner's Manual: High Voltage Battery Health, current U.S. owner documentation, reverified Oct. 25, 2026. https://www.tesla.com/ownersmanual/model3/en_us/GUID-B9807218-7291-4F68-9AFF-7C525CF498F3.html Establishes the BMS-based Battery Health evaluation; optional controlled Battery Health Test; Tesla's recommendation to use the controlled test only when there is concern about energy retention; prerequisites; duration/discharge behavior; result definition; climate-control/occupant warning; and cancel-before-unplug instruction. ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7 ↩8 ↩9 ↩10 ↩11 ↩12

  2. Nissan North America — 2024 LEAF Owner's Manual and Maintenance Information, U.S. OEM manual, manufacturer-indexed text rechecked Oct. 25, 2026. https://www.nissanusa.com/content/dam/Nissan/us/manuals-and-guides/leaf/2024/2024-nissan-leaf-owner-manual.pdf Its LI-ION BATTERY CAPACITY LEVEL GAUGE section places the capacity indicator in the trip-computer menu and describes battery capacity remaining to store power. Representation limit: the original 13.8-MB PDF exceeded the available browser-renderer limit, so the diagram and exact segment-to-percent graphics were not independently inspected; no numerical conversion is asserted. ↩ ↩2 ↩3

  3. Nissan North America — 2024 LEAF Warranty Information Booklet, printed p. 8, original U.S. manufacturer PDF visually inspected Oct. 25, 2026. https://www.nissanusa.com/content/dam/Nissan/us/manuals-and-guides/leaf/2024/2024-nissan-leaf-warranty-booklet.pdf Establishes capacity coverage below nine of twelve battery-capacity segments within 96 months/100,000 miles, subject to stated exclusions, and replacement/repair to at least nine segments; not an individual coverage decision. ↩ ↩2 ↩3 ↩4 ↩5

  4. Nissan North America — 2026 Nissan LEAF Owner's Manual and Maintenance Information, official U.S. manual PDF, reverified and visually checked Oct. 25, 2026. https://www.nissanusa.com/content/dam/Nissan/us/manuals-and-guides/leaf/2026/2026-nissan-leaf-owner-manual.pdf Establishes the Battery Information capacity percentage, its meaning and distance-since-last-update field. ↩ ↩2 ↩3 ↩4 ↩5 ↩6 ↩7

  5. Volvo Cars USA — EX90: Battery status and health, updated Dec. 11, 2025; reverified Oct. 25, 2026. https://www.volvocars.com/us/support/car/ex90/article/47d2c97fd33effd3c0a8cc3718c999b7-e1fce96acdfd4ac1c0a8b04a2efd5bbc-8664b2fa77a7e089c0a8296870d1a409/47d2c97fd33effd3c0a8cc3718c999b7-ddc7a63d5aab041bc0a8b09704e781c6-8664b2fa77a7e089c0a8296870d1a409/47d2c97fd33effd3c0a8cc3718c999b7-2ca7180393336246c0a801887d7cee30-8664b2fa77a7e089c0a8296870d1a409/ Establishes the EX90 center-display path, SoH definition and distance-since-last-estimation field. ↩ ↩2 ↩3 ↩4 ↩5

  6. Volvo Car USA / Volvo Car Canada — 2026 Warranty and Maintenance Records Information Manual, Fully Electric, revised June 2025; reverified and visually checked Oct. 25, 2026. https://www.volvocars.com/images/cs/v3/assets/bltccbab8edae0354cd/blt79f8a67d798c8d78/68befcffe94f786661a1f43a/MY2026_WTY572.06.25_Fully_Elec_Wty_Manual_Rev2_WEB_06-18-25.pdf?branch=prod_alias Establishes the free authorized-retailer SoH certificate path for EX40/EC40 vehicles without the center-display feature and separately states the warranty threshold. ↩ ↩2 ↩3 ↩4 ↩5

  7. Hyundai Motor America — 2024 IONIQ 5 U.S. Owner Manual: Battery Information, reverified Oct. 27, 2026. https://ownersmanual.hyundai.com/full_webhelp/NE1/2024/en_US/idaa8c4279dde.html Separately describes high-voltage battery for driving and 12V auxiliary battery for vehicle electronics; not a published diagnostic procedure. ↩

  8. Kia America — 2026 U.S. EV6 Owner's Manual: Main electric vehicle components, reverified Oct. 27, 2026. https://ownersmanual.kia.com/full_webhelp/CV1/2026/en_US/topics/t00232.html Separates high-voltage drive battery and 12V battery for features; does not document an official CPO SoH measurement. ↩ ↩2

  9. Kia America — 2026 U.S. EV9 (MV1A) Owner's Manual: Battery information, reverified Oct. 27, 2026. https://ownersmanual.kia.com/full_webhelp/MV1A/2026/en_US/topics/chapter1_1_2.html Separates high-voltage and 12V roles; not a CPO health-certificate requirement. ↩ ↩2

  10. Hyundai Motor America — Get the Most from Your Hyundai Battery, U.S. owner support, reverified Oct. 27, 2026. https://owners.hyundaiusa.com/us/en/resources/vehicle-health/getting-the-most-from-your-hyundai-battery Lists the complimentary two-minute battery test's RC, CCA, SOC, OCV and resistance; its stated starting/replacement context does not establish an EV high-voltage SoH test. ↩ ↩2

  11. Hyundai Motor America — Certified Used Vehicles, current U.S. program page, reverified Oct. 27, 2026. https://www.hyundaiusa.com/us/en/certified-used-vehicles The general 173-point inspection may differ for EV/HEV/PHEV vehicles; dealer is responsible for model-specific inspection. It does not explicitly promise a traction-pack SoH printout. ↩

  12. Hyundai Motor America — 2025 Certified Used Vehicles Inspection Check Sheet, HMA-P25-MP-28465 / H-25-0017, official Hyundai-hosted manufacturer PDF, source text and cover + page 2 independently visually inspected Oct. 27, 2026. https://www.hyundaiusa.com/content/dam/hyundai/us/com/pdf/cpo/HMA-P25-MP-28465_HCUV_POS_H-25-0017_InspectionChecklist_FINAL.pdf General item 21 asks for battery 'Volts Load test (CCA)' and item 2 for scan-tool checks; cover directs buyers to model-specific check sheet and notes EV/PHEV/HEV may use different inspection points. Do not present generic sheet as an EV SoH protocol. ↩

  13. Kia America — U.S. Certified Pre-Owned Program, current program page reverified Oct. 27, 2026. https://www.kia.com/us/en/cpo States 165-point inspection eligibility; page does not specify model-year EV6/EV9 HV SoH percentage, named test or standard report. Do not substitute a historical 2018 164-point form for this current program. ↩

  14. Kia America — Kia Maintenance Plan, U.S. owner-program page reverified Oct. 27, 2026. https://owners.kia.com/content/owners/en/kia-maintenance-plan.html Lists EV 'battery health monitoring' among model/plan-dependent maintenance needs but does not publish an across-model SoH percentage method or establish CPO report entitlement. ↩

  15. AVILOO — AVILOO Certified, current U.S. commercial product page, reverified Oct. 25, 2026. https://aviloo.com/en-us/aviloo-certified AVILOO describes a three-minute FLASH certificate based on vehicle data and its proprietary algorithms, related diagnostic checks, current business-customer ordering and dynamic vehicle coverage. These are provider claims, not independent ATC validation. ↩ ↩2 ↩3

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