Heat is the housing question founders ask last, and it decides where the board can go.
Focus Dock is a 3-in-1 wireless charger I designed. Three coils charge a phone, a watch and earbuds at the same time. Worst case, about 6.5 W turns into heat inside a closed plastic box.
So the layout started with the air path. Cool air comes in through vents at the bottom, rises through the open device bays and leaves at the top. The CFD run put the peak at 40.7 °C on the coil surfaces, about 20 °C above room temperature. No fan, no heat sink.
That only works because the warm parts were placed before the housing was drawn. Once the board is frozen, moving a hot part means a new board.
Before you freeze your PCB, mark what gets warm and where. Keep it near an outer wall, away from the battery and from any plastic that softens with heat.
This is point 8 of a one-page checklist I send to founders: 12 housing decisions to settle before the layout is final. Email me and I'll send it over.
