Qi2 Magnet Ring Specifications: The Precision Engineering Behind 25W Wireless Charging
Aim Magnet Engineering Team
Every Qi2 wireless charger on the market shares one critical component: a precision NdFeB magnet ring. But not all magnet rings are created equal. In this post, we dissect the exact specifications, tolerances, and material choices that separate a certification-ready magnet ring from a commodity part.
The Qi2 Magnet Ring: Dimensional Specification
The WPC Qi2 standard defines a magnet array based on Apple's MagSafe geometry. Here are the critical dimensions:
Ring Geometry
|
Dimensio |
Specificatio |
Tolerantia |
|
Diameter Exterior (OD) |
56.0 mm |
±0.05 mm |
|
Diameter Interior (ID) |
44.0 mm |
±0.05 mm |
|
Ring Width |
6,0 mm |
— |
|
Crassitudo |
0.8–1.2 mm |
±0,02 mm |
|
Planitas |
< 0,05 mm curvatura |
— |
Requisita pro performance magnetica
Fortitudo retinendi anuli magnetici Qi2 est functio trium variabilium: F = Br × Vmagnet × 1/dgap, ubi Br est densitas fluxus residui, V est volumen magnetis, et d est distantia inter spatia.
Gradus magnetorum recommendati
|
Gradus |
Br (kGs) |
Hcj (kOe) |
BHmax (MGOe) |
Uti causa |
|
N48 |
13.8–14.2 |
≥11 |
46–49 |
Chargers ad pretium minimum, casus tenuis |
|
N50 |
14.0–14.5 |
≥11 |
49–52 |
Chargers Qi2 ordinarii |
|
N52 |
14.3–14.8 |
≥11 |
51–54 |
Chargers praemium, montes pro automobilibus |
|
N52SH |
14.3–14.8 |
≥20 |
51–54 |
Altis temperaturis (pro automobilibus, rapidus impetus 25 W) |
N52 praebet vim retinendam circa 15 % maior quam N48 ad eundem volumen. N52SH necessarius est pro Qi2.2 25 W.
Cur tolerantia momenti habet: Comparatio ex vita reali
Considera duo annula magnetica, utraque notata "compatibilia cum Qi2":
|
Parameter |
Annulus oeconomicus |
Annulus Aim Precision |
|
Tolerantia OD |
±0.10 mm |
±0,02 mm |
|
Tolerantia Crassitiei |
±0.05 mm |
±0,02 mm |
|
Fortitudo tenens ad interstitium 1 mm |
~800 gf |
~950 gf (+19%) |
|
Ratione successus certificati WPC |
~60–70% |
> 95% |
Coating: Resistentia ad corrosionem
Magneta NdFeB rapidissime oxydantur sine opportuno revestimento. Pro applicationibus Qi2:
|
Coating |
Crassitudo |
Nebula salina |
Commendatum Pro |
|
Ni-Cu-Ni |
15–25 μm |
48h |
Usus indoor generalis |
|
Epoxy + Ni |
20–30 μm |
96H |
Ambiens humidus, bancae potentiae |
|
Parylenum |
3–5 μm |
200 h+ |
Medicinalis, summa qualitas |
Thermicum: 15 W contrā 25 W Qi2.2
|
Aspectus |
15 W Qi2 |
25 W Qi2.2 |
|
Expositio temperātūrae magnētī |
circa 40–50 °C |
circa 55–70 °C |
|
Gradus Recommandatus |
N48–N52 |
N50SH–N52SH |
Regula: ad 25 W, magnēta communia gradūs N amittunt fortitudinem magneticam 3–5 % intra mēnsēs. Gradus SH (Hcj ≥ 20 kOe) est minimum quod ad Qi2.2 recōmmendātur.
Checklist: Specifying Qi2 Magnet Rings
- OD 56.0 mm ±0.05, ID 44.0 mm ±0.05
- Flatness < 0.05 mm, Grade ≥ N50 (N52SH for 25W)
- Ni-Cu-Ni coating ≥ 15 μm
- Segmented arc configuration (18+ segments preferred)
- Gauss measurement data per production batch
- WPC certification test reports available
- Supplier provides magnetic field simulation support
De AIM Magnet
We provide certified Qi2 magnet rings in N48 through N52SH grades, with ±0.02 mm precision, full batch traceability, and magnetic field simulation support. ISO 9001:2015 certified.
