Wireless charger coil

Buyers must prioritize Inductance (L), DC Resistance (DCR), and the Q Factor (Quality Factor). For standard Qi-compliant applications, the inductance typically ranges from 6.3uH to 24uH. A lower DCR is critical to minimize heat generation and maximize energy transfer efficiency. Additionally, ensure the coil uses high-quality Litz wire to reduce the skin effect in high-frequency operations.

The most important standard is the WPC (Wireless Power Consortium) Qi Standard. Ensure the supplier provides coils that meet Qi v1.2.4 or v1.3 specifications. For automotive applications, the components must be AEC-Q200 qualified. Furthermore, verify that the ferrite shielding material is of high permeability to prevent EMI (Electromagnetic Interference) and comply with FCC and CE EMC requirements.

The ferrite sheet or magnetic shield is vital for directing the magnetic field toward the receiver and protecting the device's internal electronics. You should check the thickness (typically 0.5mm to 2.5mm) and the magnetic permeability of the ferrite. High-performance coils often use flexible sintered ferrite sheets to maintain efficiency in slim consumer electronics.

Coils are categorized by power requirements: 5W-15W coils are standard for smartphones and TWS earbuds, while 30W-100W high-power coils are used for laptops and medical devices. For wearable tech like smartwatches, micro-coils with a diameter of less than 20mm are required. Always match the coil geometry (round, square, or oval) to the physical constraints of your product housing.

Always request a First Article Inspection (FAI) report and a small batch of samples before proceeding to mass production. Utilize third-party inspection services (like SGS or Intertek) to perform Salt Spray Tests and High-Temperature/Humidity Tests at the factory. On Made-in-China.com, prioritize Audited Suppliers who have undergone comprehensive on-site verification of their manufacturing capabilities.

Focus on the Total Cost of Ownership (TCO) rather than just the unit price. Negotiate based on volume-based pricing tiers (e.g., 1k, 10k, 50k units) and ask for transparency in raw material costs, especially for copper and ferrite. Request a long-term price stability agreement to protect against fluctuations in copper commodity prices.

Wireless charger coils contain ferrite magnets which can be classified as 'Sensitive Goods' in air freight. Ensure the supplier uses anti-static packaging (ESD bags) and provides magnetic shielding packaging if required by the carrier to avoid interference with aircraft navigation. For sea freight, ensure vacuum packaging or desiccants are used to prevent copper oxidation during long transit times.

Use secure payment methods such as Letters of Credit (L/C) for large volumes or Escrow-based trade assurance services provided by platforms like Made-in-China.com. Never transfer funds to private bank accounts; always ensure the beneficiary name matches the registered company name on the business license and the platform profile.