How do I buy a used EV battery pack safely?
Used EV packs operate at 200–800V DC — enough to kill on contact. Only buy from sellers who can document the pack's state-of-health (SOH %) and module count. Shipping is regulated under 49 CFR 173.185: damaged packs are forbidden by most carriers, and undamaged packs require UN3480/UN3481 hazmat paperwork. Never disassemble a pack without high-voltage certification.
An EV traction battery is the most hazardous single part you will buy at a salvage yard. The pack stores enough energy to weld a wrench to itself and enough voltage to stop a heart. Treat every pack as live.
Before paying, confirm three things in writing: state-of-health percentage (most BMS readouts give this), module configuration (e.g., 16 × 50 Ah), and whether the pack was ever in a fire, submerged, or impacted in the area of the case. Any 'yes' on the third question and you should walk.
Shipping is regulated. Lithium-ion packs over 100 Wh ship as UN3480 (loose) or UN3481 (installed). Most ground carriers (FedEx, UPS) require advance hazmat approval; some refuse damaged packs entirely. Sea and air freight have additional restrictions per IATA DGR. Budget for specialty hazmat freight, not standard parcel.
Storage and handling. Keep the pack in a cool, dry, ventilated area away from flammables. Do not stack heavy items on top. If the case shows any swelling, hissing, or thermal discoloration, isolate it outdoors and call your local fire department's hazmat line.
Disassembly requires certification. OSHA, NFPA 70E, and most state codes require electrical PPE and either a Level 1 EV technician certification or a licensed electrician for HV work. Insurance will not cover injuries from unqualified disassembly.
Frequently asked
How do I check an EV battery's state of health?
Most modern packs report SOH through the OBD-II port using a brand-specific app (Tesla Toolbox, Leaf Spy, Bolt SOH tool, etc.). Anything below 80% SOH is generally considered service-life-end for traction use, but may be fine for stationary storage projects.
Can I ship an EV battery pack via FedEx or UPS?
Only with prior hazmat approval and proper UN3480/UN3481 packaging. Damaged or recalled packs are forbidden. Specialty carriers (Patriot Battery, Tradebe) handle damaged packs at significantly higher cost.
Is it legal to repurpose an EV pack for home solar storage?
Yes in most jurisdictions, but the inverter/charger must be UL-listed for the chemistry, the installation must comply with local electrical code (NFPA 70 Article 706), and many AHJs require permit and inspection. Check with your local building department before installing.