Qi2 magnetic wireless charger: 15W and Qi2.2 25W builds
Two charging profiles, one magnet ring. 15W is the volume build and 25W is the new ceiling, and the difference between them is mostly heat, not the coil.
Builds in this line (2)
The two Qi2 builds
Same ring, same alignment, different power budget and a different thermal problem.
15W against 25W
The coil is similar. What changes is the power stage, the heat path and the phone that can use it.
| Build | Output | Profile | Phone it suits | Main risk |
|---|---|---|---|---|
| 15W Qi2 | 15 W | Qi2 magnetic (MPP) | Any Qi2 phone, iPhone 12 and later | A case that is too thick for the ring |
| Qi2.2 25W | 25 W | Qi2.2 magnetic | A phone that supports Qi2.2 | Heat, and an adapter that cannot hold 25W |
A 25W build does not make a 15W phone charge faster. It holds 25W with a Qi2.2 phone and falls back to a lower profile with everything else, which is why the phone list decides the build.
The magnet ring is a heat decision
A magnetic charger does not have to find the coil. The ring puts the phone coil over the charger coil and holds it there, and alignment is most of the efficiency difference between a magnetic charger and a flat pad.
At 15W a misaligned pad gets warm. At 25W the same misalignment becomes a thermal limit: the charger derates, the phone derates, and the last five watts never arrive. That is why Qi2.2 hardware spends its cost on shielding and the heat path rather than on the coil.
- Qi
- The original inductive standard, up to 15W depending on profile
- Qi2
- Magnetic Power Profile, 15W, alignment by a magnet ring
- Qi2.2
- The 2025 update, 25W over the same magnetic alignment
- MPP
- Magnetic Power Profile, the part of Qi2 that uses the ring
- Derating
- The charger reducing power as its temperature rises
Which build to order
The answer follows the phone list, not the wattage on the box.
- A mixed fleet of phones: 15W. The 25W build cannot show its ceiling on a phone that does not support Qi2.2.
- A premium phone list: 25W, with the adapter quoted alongside it. The charger is not the only part that has to support 25W.
- Retail packaging claims: match the claim to the profile. A 15W build sold as 25W is a return and a review.
- Private label programmes: fix the profile before the housing is tooled, because the power stage changes the internal height.
Qi2 certification is per model and is listed on the WPC product database. Ask for the model number and the certificate file, not for a logo.
Before the order
Three things that are cheaper to fix on the drawing than in production.
- Phone list: which models have to reach 25W, and which only need 15W.
- Power supply: whether the adapter ships in the box, and what it is rated for.
- Case clearance: the ring holds through a thin case, not through a wallet case.
- Profiles
- Qi2 15W, Qi2.2 25W
- Alignment
- Magnet ring
- Input
- USB-C
- Ask for
- Model number, certificate file, adapter rating
Send the device list, get a written configuration.
Phone models, quantities and destination market is enough. The reply is a build, a specification sheet and the certificate list for each line item.