UL 1974 is the safety standard for evaluating used batteries before they are repurposed — the framework a retired EV battery pack is sorted and tested against before it can be built into a second-life product, usually stationary storage. A pack that leaves a car carries an unknown history, so the standard exists to answer one question with evidence: is this battery, or its modules, safe and fit to work again in a different job? It is a standard, not a law; testing and certification against it are done by accredited laboratories.
Key Takeaways
- UL 1974 is the standard for evaluating used batteries before repurposing — sorting, grading and safety testing.
- It exists because retired packs have unknown histories; condition is measured, not assumed.
- Packs that fail or are too degraded go to recycling; passing packs become certified second-life products.
- Owners never handle this themselves — packs move through dealers, manufacturers and specialist firms.
Why a Retired Pack Cannot Simply Be Reused
Packs leave vehicles for very different reasons: the car was written off, the capacity faded past usefulness, or a warranty claim swapped the pack out. Two packs of the same age can be in completely different condition, and damage is not always visible from outside. That is why reuse starts with measurement, not installation — the same measured-health principle behind our guide to how to check EV battery health, applied at industrial scale. Until a pack has been evaluated, nobody honestly knows which of the routes below it belongs on.
What the Evaluation Covers
At scope level, UL 1974 covers the evaluation of batteries for repurposing: the sorting and grading of cells, modules and packs, and the safety examination a used battery passes through before a repurposer builds it into a new product. It sits in the middle of a battery’s story:
| Stage | What happens | Who does it |
|---|---|---|
| In the car | The pack works as designed, under the vehicle’s own safety standards | The car maker |
| Between lives | The pack is discharged, inspected, tested and graded under UL 1974 | Specialist repurposing firms, with accredited test labs |
| Passes evaluation | Modules or packs are built into a second-life product, which needs its own product certification | The repurposer, as the new product’s manufacturer |
| Fails or too degraded | The pack goes to recycling, where its metals are recovered | Licensed battery recyclers |
What UL 1974 is not matters as much: it is not a repair manual, not a recycling process, and not a route for an owner to convert a pack at home. Handling a traction battery is high-voltage specialist work, whichever direction it travels.
What It Means for Owners and Buyers
- Your old pack enters this chain without you. Warranty returns, dealer replacements and written-off cars move packs to manufacturers and licensed handlers — the owner routes are the ones in our guide to whether an EV battery can be replaced or repaired.
- Buy the finished product, not the raw pack. A second-life storage system should be a certified product built from evaluated batteries. A loose used pack offered cheaply has skipped exactly the step UL 1974 exists for.
- Ask the standard question. A seller of repurposed batteries should be able to say what their packs were evaluated against. “Tested” without a named standard is a claim, not a certification.
The Same Question Applies to New Equipment
Certification is the habit to keep. New charging equipment carries its own listings — the EV-ACT5006T 48A Level 2 wall charger is ETL listed, tested by a nationally recognised laboratory in the same system that certifies against UL standards. Whether a battery is on its first life or its second, the useful question is identical: tested to what, and by whom? The full range is on our products page.
Frequently Asked Questions
Is UL 1974 a law?
No. It is a voluntary safety standard. Manufacturers and repurposers have products tested against it by nationally recognised testing laboratories, and buyers, insurers and authorities having jurisdiction may ask for that certification as evidence a used battery was properly evaluated.
Does every retired EV battery pass the evaluation?
No — passing is not the point; sorting is. Evaluation grades packs and modules by their measured condition. Those fit for another job go forward to repurposing, and those that are damaged or too degraded go to recycling instead.
Can I have my own car’s old pack evaluated and keep it as a home battery?
In practice, no. The evaluation is one step in an industrial repurposing process carried out by specialist firms on packs they take in through trade channels. Owners hand packs over through dealers and manufacturers; the certified end product is what comes back to the market.
Related Reading
- Can an EV Battery Be Replaced or Repaired?
- How to Check EV Battery Health
- Does an EV Battery Degrade Over Time?
