Qi 2.2 Wireless Charging: What the Newer Spec Changes for Product Roadmaps
Qi 2.2 wireless charging explained for product teams: higher power steps, magnet tolerances, thermal implications, certification evidence and roadmap timing.
Wireless charging standards evolve in steps rather than continuously, and each step is really a statement about power and tolerance. For a product team, a new revision is a change to the thermal budget and to the certification evidence, not simply a new number for the packaging.
This article sets out what a later Qi generation changes in practice and how to plan a roadmap around it.
What is Qi 2.2 wireless charging?
A later Qi generation with higher power.
Qi2 introduced magnetic alignment to the Qi standard; a later revision raises the available power steps and tightens the tolerances a compliant product must meet.
The Qi standard is maintained by the Wireless Power Consortium, and its magnetically aligned profile is what made magnetic charging a cross-brand format rather than a single-vendor feature (Wireless Power Consortium: Qi). Each revision adjusts the power steps, the alignment tolerances and the test requirements that a certified product must satisfy.
For a brand the practical question is not the revision number but which power step and which tolerances apply to the products being planned, because those determine the coil design, the thermal path and the test programme.
Power steps: 15W, 25W and what the device accepts
Wireless power is limited by the device as well as by the pad. A phone that accepts a lower rate will charge at that rate on a higher-rated pad, and the pad’s rating describes its capability rather than the outcome for a specific device.
That distinction belongs on the product page in the same way as a charger’s port split: state the pad’s capability and the alignment requirement, and avoid promising a charge time for a device the vendor has not published one for.
Magnet arrays and alignment tolerances
Alignment tolerance is what makes a magnetic format work across cases, handsets and pad designs. A tighter tolerance in a later revision is a benefit for the user and a constraint for the manufacturer, because coil placement, magnet grade and housing thickness all contribute to staying inside it.
For a supplier, that translates into dimensional control on the assembly and a test that verifies alignment rather than assuming it from the drawing. Both are specified in the manufacturing documentation rather than added at inspection.
Thermal implications of higher wireless power
Higher transfer power means more absolute loss even at the same efficiency, and it is concentrated in the coils and the phone’s charging circuit. Compact multi-device stations have the least room to spread that heat, which is why thermal design is the work item that decides whether a higher power step is usable in a given format.
The design responses are the familiar ones: a thermally conductive path from the coil to the housing, derating behaviour driven by temperature sensing, and a housing that allows air to move. WECENT’s wireless platforms include thermal design as part of the specification and over-temperature protection with the rest of the protection set, verified through functional testing and load aging at the quality control gates.
Certification evidence for a magnetic pad
Two evidence streams matter. The first is Qi-related certification for the inductive function, which comes from the Wireless Power Consortium’s programme (Wireless Power Consortium). The second is the market’s EMC and radio compliance, such as the FCC Part 15 framework in the United States (47 CFR Part 15) or the radio equipment directive in the EU (Directive 2014/53/EU), with adapter efficiency rules applying to any supply shipped with the product (Regulation (EU) 2019/1782).
Keeping the two streams separate matters when a product changes: a new coil design affects the first, while a change to the power supply affects the second.
Roadmap timing: when to retool an existing platform
The decision to re-tool for a newer revision depends on three questions: whether the target devices can use the higher power step, whether the format has the thermal headroom for it, and whether the channel is asking for the claim. If any answer is no, the existing platform remains the better commercial choice.
Where the answer is yes, the practical sequence is to validate the coil and thermal design first, then update certification evidence, then release the SKU. Starting with the housing cosmetics reverses that order and usually costs a second tooling round.
Compatibility with older Qi and magnetic devices
A newer magnetic pad should still charge older Qi devices, because the underlying standard is backward compatible within its framework. The practical limits are alignment, since an older phone has no magnet array, and the pad’s detection behaviour with light loads such as earbud cases.
WECENT builds magnetic pads and multi-device stations across its wireless charger range range, quotes from a written specification through the OEM/ODM programme, and starts at 200 pcs per model for a pilot, with certification planning and batch traceability included. Packaging and transit performance can be validated against a published protocol (ISTA).
For buyers, the practical roadmap rule is to separate the two things a revision changes: the electrical envelope and the mechanical tolerance. A new power step normally requires a thermal validation, while a tighter alignment tolerance requires a dimensional review of the magnet housing. Treating them as a single change is what turns a small update into an extra tooling round, and it is the most common reason a wireless product programme slips by a quarter.
FAQ
Is Qi2 15W or 25W?
Both figures exist in the standard’s power steps, and which applies depends on the revision and on the device. The pad’s rating describes its capability; the phone decides the rate it accepts, so a product page should state the pad’s capability rather than a promised charge time.
What is the difference between Qi2 and a later revision?
Each revision adjusts power steps, alignment tolerances and test requirements. For a manufacturer the practical effects are coil design, magnet arrangement and the thermal budget, not the visible appearance of the product.
Will a newer magnetic pad charge an older iPhone?
Yes, within the Qi framework. Older phones without a magnetic array charge on the pad but must be positioned manually, and the rate is set by the phone’s own wireless capability rather than by the pad’s rating.
What certification does a magnetic charging pad need?
Two streams: Qi-related certification for the inductive function, and the market’s EMC and radio compliance requirements. Any adapter shipped with the product also carries the external power supply documentation that market requires.
When should a brand retool for a higher wireless power step?
When target devices can use the higher step, the product format has the thermal headroom for it, and the channel asks for the claim. Validate the coil and thermal design first, then update certification evidence, then release the SKU.
Planning a wireless charging roadmap?
Share the device targets, product formats and markets, and WECENT will confirm the coil and thermal design, certification path and MOQ from a written brief.
