Teardown of Apple 40W dynamic power adapter with 60W max

Original Article ↗ Hacker News Discussion ↗

Link and access issues

  • Several readers reported the site being down or very slow; others hit Google Safe Browsing warnings.
  • Archive mirrors were shared as workarounds.

What’s technically notable

  • Internals show a very dense GaN-based design, with a thermistor used to dynamically adjust power output based on temperature.
  • Supports USB PD 3.2 SPR AVS (Adjustable Voltage Supply), which some noted is still rare in chargers.

60W peak / 40W sustained behavior

  • Multiple comments referenced tests elsewhere showing ~15–18 minutes at 60W before stepping down to 40W.
  • Consensus is that temperature is the limiting factor: the adapter boosts briefly for “quick top‑ups,” then backs off to avoid overheating the brick and the phone.

Compatibility, AVS vs PPS

  • One camp: any decent 40W+ USB‑PD charger will charge iPhone 17 models at full rated speed; AVS is not required and practical gains are negligible.
  • Another camp speculated AVS might slightly improve efficiency and sustained speeds under specific thermal conditions, though this was challenged with detailed efficiency math.
  • Debate on Apple’s choice of AVS but not PPS (Programmable Power Supply): some see it as ecosystem lock‑in; others point out AVS is a USB‑IF standard and just “along for the ride” with new PD revisions.

Comparisons to other chargers and form factors

  • Many argue there’s nothing uniquely special versus compact GaN options from Anker, Ugreen, SlimQ, Lenovo, etc., especially multi‑port units.
  • Others find it “mildly interesting” as a very packed single‑port design and expect similar folding‑pin UK/EU variants.
  • Complaints that EU/UK plug geometry often negates compactness gains seen with US plugs.

Safety, heat, and quality

  • Concerns about very cheap high‑power AliExpress chargers: questions over UL/CE compliance, fusing, and fire risk; others claim newer Chinese designs often include basic protection.
  • Discussion of how hot small GaN bricks can legally get; thermal cutoffs and “toasty but not too hot” measurements were referenced.
  • Reminders that hotels’ built‑in USB ports are usually very low power.

Charging behavior, battery health, and user preferences

  • Multiple users intentionally avoid fast charging, preferring slow (5–10W) or wireless to reduce stress and heat, though others note wireless often increases heat.
  • General technical view: device, not charger, controls current; modern phones manage battery temperature and SoC intelligently (80% limits, “optimized charging,” fast‑charge toggles).
  • Several argue fast charging within manufacturer limits causes minimal extra degradation compared to keeping batteries at high state of charge for long periods.
  • Some aim to keep phones 5–10 years and therefore obsess over slow charging; others with large managed fleets report batteries rarely being the limiting factor within ~2–3 years.

Repairability and UX odds and ends

  • Praised teardown photography but disappointment that the adapter is glued, making it non‑repairable and future e‑waste.
  • Some admired Apple’s mechanical folding‑pin designs; others complained about disabled pinch‑to‑zoom on the teardown site and shared browser workarounds.
  • Side discussion on integrated in‑wall USB‑C PD outlets as an alternative to wall warts.