Yes, if the battery has been screened, rebuilt as a proper stationary system and documented. YouPower Recycling, our Battery Disassembly Center, screens used lithium batteries and decides whether they are fit for second life or at end of life. Our page on lithium battery recycling shows that route step by step. For a company that must count on its storage for years, a new battery often remains the safer choice. This article shows where the line lies.
The offer sounds tempting. A trader has used EV modules for much less than a new battery. Your forklift fleet moved to lithium, and the old packs still hold a charge. On forums, people say they run a house on a battery from a wrecked car or an old Nissan Leaf.
What the price per kWh does not show is everything you do not know. How healthy are the cells? Was the pack ever in a crash or overheated? Will the car's battery management system even talk to your inverter? And who is liable when it fails? Under EU rules, whoever puts a repurposed battery back into service takes on the duties of a producer. If nobody else did that job, it can end up with you.
Giving a battery a job it was not built for is not new to us. Special Renting Van Zele in Zele rents out forklifts and aerial platforms and runs without a grid connection on a system we built. HLN reported that surplus solar power on that site is stored in the battery of a forklift truck.
What is a second-life battery, and how is it different from a refurbished one?
A second-life battery is a used battery that gets a different job than the one it was designed for. The EU Battery Regulation calls this repurposing. The classic example is an EV battery that ends up as stationary storage in a building.
Several words float around for used batteries. They do not mean the same thing, and the difference matters for what you buy.
| Term | What happens to the battery | Same job or a new one? |
|---|---|---|
| Re-use | Used again as it is | Same job |
| Repair or revision | A fault is fixed: a cell, a module or the battery management system | Same job |
| Remanufacturing | All cells and modules are taken apart and evaluated; capacity is restored to at least 90% of the original rating | Same job |
| Repurposing (second life) | Used for another purpose than the one it was designed for, for example from car to stationary storage | New job |
| Recycling | Dismantled and shredded to recover the raw materials | End of life |
Source: definitions in Regulation (EU) 2023/1542, article 3. One detail matters for a business: an EV battery that is repurposed for industrial use counts as an industrial battery under the same regulation.
Not every tired battery needs a second life. Our team of three certified battery experts revises installed batteries and takes on maintenance and repairs of existing battery systems. A faulty module does not always mean the whole battery is finished.
How much life does a second-life battery still have?
Often more than people expect when it leaves the car. Argonne National Laboratory, a US government lab, writes that an EV battery may then still have about 80% of its usable capacity. It can still have up to 10 years of life left in another application.
Belgian examples point the same way. Febelauto, the take-back organisation for vehicles, writes that modules no longer fit for a car can serve another 10 years in stationary storage. In 2019 Umicore in Olen and ENGIE turned 48 used batteries from Renault Kangoo vans into one storage system. It holds 720 kWh at 1.2 MW and was offered to the primary reserve on the Elia grid.
But an average of 80% says nothing about your battery. Two packs of the same model can age very differently, depending on heat, fast charging and how deep they were cycled. That is why every battery needs its own measurement, not a label or a model year.
Where can a second-life battery work for a business?
Where the new job is lighter than the first one. A car asks for high power and long range. A stationary battery that smooths a peak or covers a power cut asks less of each cell.
Argonne lists the uses that already exist:
- Storage behind the meter: back-up power and smoothing peak demand at homes, businesses and industrial sites, mostly to cut electricity costs.
- A buffer for fast chargers: battery systems of 50 to 300 kWh that lower the peak a DC fast charger pulls from the grid.
- Back-up for telecom masts and data centres: telecom is today the largest second-life use worldwide.
- Low-power vehicles: golf carts and some industrial vehicles, such as forklifts, need less power than a car.
A good fit
- peak shaving with modest power
- back-up for a few critical loads
- a buffer for EV chargers
- a pilot or test site
A poor fit
- batteries of unknown origin or with a crash history
- heavy motors that need high power
- storage your continuity depends on for ten years
- any pack nobody has measured
Want to see what a battery does against peaks on a business site, new or used? Our article on battery storage for businesses explains the savings logic.
Are second-life batteries safe for stationary storage?
They can be, but the safety comes from the process, not from the cells. A used battery is safe to install when it has been screened, rebuilt with a suitable battery management system and documented as a new system.
- Screening first: at our Battery Disassembly Center we determine the type and features of a battery and assess its condition. We check how far the cells are damaged and take extra safety measures where needed.
- A new battery management system (BMS): the BMS is the electronics that watches every cell. Argonne warns that the BMS from the car will likely not suit a second-life use. Each new use needs its own, properly engineered BMS.
- No mixing: modules from different cars differ in shape and chemistry. Mixing them in one system adds variability, Argonne notes.
- Tested as a system: EU law requires stationary storage to be safe in normal use, with safety tests in its technical documentation. That documentation must be reviewed when a battery is repurposed.
- A recognised method: the standard UL 1974 sets requirements for sorting and grading batteries that are meant for repurposing.
Important
A battery from a crashed car, a swollen or leaking module, or a pack with an unknown history does not go into your building. It goes to screening, and if needed to recycling.
Once it is on your site, a second-life battery follows the same placement rules as a new one. Our article on fire safety, permits and insurance for a business battery explains what the fire service and the AREI ask.
Offered a used battery, or not sure your old packs are still good? Call us and we will tell you the next step.
Can you use an old forklift battery as energy storage?
Yes, it is done, but a forklift battery is built for a forklift, not for a building. At Van Zele, the forklift rental company in Zele, HLN reported that surplus solar power is stored in a forklift battery. Whether that is wise on your site depends on the chemistry.
Lead-acid traction batteries give off hydrogen while they charge. The German industry association ZVEI explains, based on the standard EN 62485-3, that ventilation must keep hydrogen below 4% in the air. Above that, the mixture can explode. The standard also asks for 0.5 metres of free air between the cell openings and any spark or flame. Flooded batteries lose water, so someone has to top them up.
Lithium forklift batteries are cleaner, but their electronics were made to talk to the forklift and its charger. Check that the BMS can communicate with your storage inverter. If it cannot, the pack needs a new BMS before it can run as stationary storage.
Moving your fleet from lead-acid to lithium? Our article on charging forklifts from your own solar power explains what changes on the site. If you would rather have storage that was built for the job, a business battery is designed for daily cycling from day one.
What does the EU Battery Regulation ask of a second-life battery?
Proof of health, paperwork for the sale and, from 2027, a new passport. Regulation (EU) 2023/1542 sets these rules for industrial, EV and light-vehicle batteries that get a second life.
- Proof of health: a used battery prepared for a new job is only no longer waste when its holder can show a state-of-health test. That record must confirm the battery can do its new job (article 73).
- Paperwork and transport: an invoice or a sales contract documents the further use. The battery must be protected against damage in transport (article 73).
- Health data for the buyer: since 18 August 2024 the BMS of stationary storage and EV batteries must hold state-of-health data. Whoever legally bought the battery gets read-only access, for example to judge whether it can be repurposed (article 14).
- A new passport: from 18 February 2027, industrial batteries above 2 kWh need a digital battery passport. A repurposed battery gets a new passport linked to the original one (article 77).
- A new owner of the duties: the obligations move to the company that places the repurposed battery on the market. The same goes for whoever puts it into service (article 77).
Watch out
Ask the supplier in writing who places the repurposed system on the market. If you buy loose modules and build the system yourself, that role can land with your company.
Second-life or new battery: which one should a business choose?
For most companies a new battery remains the safer choice. Second life fits where lower capacity is fine and every battery comes with full documentation.
| Question | Second-life battery | New business battery |
|---|---|---|
| Capacity at the start | Lower, measured per battery (an EV battery may still hold about 80%) | Full rated capacity |
| Proof of health | State-of-health record per battery | Factory data and datasheet |
| Battery management system | Must be engineered for the new use | Designed for stationary storage |
| Years of use left | Up to about 10 years, depending on the battery | A full first life |
| Warranty | Depends on the repurposer: ask in writing | Manufacturer and installer warranty |
| Battery passport (from 2027) | New passport linked to the original | New passport |
Sources: Argonne National Laboratory; Regulation (EU) 2023/1542. What a good warranty on a business battery covers is in our article on warranty and maintenance of a business battery.
Our verdict
Choose second life for a pilot, a test site or a modest back-up. Each battery then needs a state-of-health record, a suitable BMS and a supplier who signs as producer. Choose new when the battery must carry your peak or your continuity for years. Then a system designed for storage is the better investment.
What should you ask a supplier of second-life batteries?
Six questions separate a serious offer from a gamble. Ask them before you compare prices.
Where does it come from?
Brand, model, chemistry and age, and whether the car or machine was ever in a crash, a fire or a flood.
What is its state of health?
A measured record per battery or module, with the test used and the date, not an average for the batch.
Which BMS runs it?
A BMS designed for stationary use that talks to your inverter, not the original car electronics.
Who is the producer?
The company that places the system on the market, with its technical documentation and, from 2027, the battery passport.
What does the warranty say?
Capacity at delivery and after a set number of years, and who comes when it fails.
What happens at the end?
Who takes the battery back and where it is recycled. Our article on what a company must do with old lithium batteries explains the rules.
What happens when you contact YouPower Recycling?
We start with a measurement, not with a promise.
- Step 1: You tell us what you have. Type, origin, number and state of the batteries, and where they are.
- Step 2: Intake and assessment at our Battery Disassembly Center. We determine the type and features, assess the condition and check the cells for damage.
What decides a battery's second life
- Step 3: Screening. A battery that is found suitable can be reused in second life applications. If not, it is treated as end of life after the measurements, and taken apart safely.
- Step 4: Need storage rather than a used battery? Then we size and design a business battery system around your consumption, install it and keep monitoring it.
Frequently asked questions
Is a second-life battery cheaper than a new one?
The purchase price per kWh can be lower. Compare the whole project, though: testing, a new BMS, integration, fewer years of use and the paperwork. For a small pilot the balance can be positive; for a site that relies on its battery, count the risk too.
Can you connect a used EV battery straight to a solar inverter?
No. The battery management system from the car was made for the car. A second-life use needs its own BMS that monitors the modules and talks to the inverter, and the system needs its own safety documentation.
Does a second-life battery need a battery passport?
From 18 February 2027, yes, when it is an industrial battery above 2 kWh placed on the market or put into service. A repurposed battery gets a new passport, linked to the passport of the original battery.
What happens to a second-life battery at the end?
It becomes a waste battery and goes back through a take-back scheme or a specialised recycler. There it is dismantled and shredded, and its battery passport ceases to exist once it has been recycled.
Can a company give its old batteries a second life?
Only a measurement can tell. Batteries that pass screening can go to second life applications; the others are end of life. Keep old batteries dry, cool and apart until they are assessed, and never keep a damaged one indoors.
Wondering whether your battery deserves a second life?
Tell us what you have or what you are being offered: EV modules, forklift packs, a storage system or loose cells. We will tell you what screening shows, whether second life makes sense and when a new battery is the wiser choice.
Sources
- EUR-Lex: Regulation (EU) 2023/1542 on batteries and waste batteries (articles 3, 12, 14, 73 and 77)
- Argonne National Laboratory: Battery second life, frequently asked questions (2020)
- UL Solutions: UL certification helps promote repurposing of EV batteries (UL 1974)
- Febelauto: what Febelauto does with end-of-life EV batteries
- Agoria: Umicore Olen and ENGIE turn 48 EV batteries into an industrial battery system (2019)
- ZVEI: ventilation of battery charging rooms for lead traction batteries, leaflet 14 (2020)