Wireless charging returns are almost never firmware problems. Coil architecture, alignment tolerance and thermal design decide whether the pad works.
Wireless charging is the one accessory category where a technically correct product still gets returned. The complaints are always the same: it charges slowly, it stops overnight, it gets hot. Almost none of them are firmware problems — they are coil alignment, thermal design and protocol matching decisions made before tooling.
Inductive charging couples two coils through a few millimetres of plastic. Move the phone's coil out of the sweet spot and coupling collapses: the transmitter pushes more power, most of it becomes heat, and the receiver throttles. From the user's side that reads as "it stopped charging".
| 5 W | 15 W | Magnetic 15 W | |
|---|---|---|---|
| Alignment tolerance | Generous | Tight | Fixed by magnets |
| Heat at the case | Low | Noticeable | Manageable |
| Foreign object detection | Nice to have | Required | Required |
| Validation effort | Light | Heavy | Moderate |
| Best for | Giveaways, hotel nightstands | Retail where the brand controls the phone range | Premium retail, daily-use products |
Coil positions differ between models and generations. Validate across a representative set, including the largest and the smallest, with cases on.
On a stand or a car mount, gravity moves the phone. A design that works flat can fail at an angle, because the phone slides off the sweet spot.
Foreign object detection that is too sensitive stops charging with a metal ring case on; too lax and a coin on the pad becomes a heating element. It needs tuning, not just enabling.
Technically yes, but the alignment window is small enough that users will miss it. Multi-coil or magnetic is the practical route.
A properly designed ring does not. Poorly placed magnets affect compass and, on some models, the camera module — which is why the ring geometry is specified, not improvised.
Up to roughly 3 mm, depending on coil design. Thicker rugged cases and anything with metal in them need testing, not assumptions.
Qi certification if you use the mark, plus the usual radio and safety approvals for each market. See certifications and compliance.
Yes — logo, colour and finish, subject to MOQ. See MOQ and pricing.
Only at 5 W, where alignment is forgiving. Above that, the return rate typically costs more than the feature earns.
Plan for a phone matrix and a thermal campaign, not a single bench test. Related: power bank ODM runs a comparable cycle.
Yes — nightstand units, desk pads, car mounts. The coil and thermal work is the same; the housing changes.