Running the fin on less than 12.5 Watts

balenaFin
1

I understand the spec sheet says 12.5 watts per device, and I understand that what I am about to propose may never work.

Our use case requires serval of the fins to be powered by daisy-chaining active or passive PoE.
Now some of you might read this and think daisy chaining active PoE? Who would do that? But ignore that for now.

This post here says that the draw rate on the Pi3B+ under load is 690 mA at 5.2 V so 3.588 Watts.

Even @sqweelygig posted once that he attempted to boot the fin on just 2.7 watts and experienced a brownout quote:

when the Pi started doing anything serious

This implied to me that he got some use out of it at even that very low wattage.

Overall my un-tested conclusion is that fin 1.1 will only draw less than 5 watts peak per device via it’s PoE connection and the real load will be somewhere around 3 watts.
This assumes our use case:

  • No HDMI
  • No ePCI router
  • A low power USB wifi adapter

Is this a terrible idea? Will my devices get deployed and then later be browned out by a software update (that somehow increases the power requirements)?

I will be testing this over the next few weeks and keep this thread updated.

Thanks!

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