HomePod mini works with 18W power supplies after 14.3 software update

But the HomePod Mini (I got one for Christmas) comes with a 20W power adapter so...

That's cool that Apple was able to do this with a software update.

crowley said:

That's cool that Apple was able to do this with a software update.

Agreed - I was reading in another (MagSafe duo?) thread about USB power profiles; the way I understand it is newer USB power supplies offer a different range of voltage and current combinations, so 18 watts with one supply is not the same as 18 watts in another. I wonder if the HomePod mini never really needed 20w, just the 20w power profile and the firmware update simply allows it to use the 18w profile.

MplsP said:

crowley said:

That's cool that Apple was able to do this with a software update.

Agreed - I was reading in another (MagSafe duo?) thread about USB power profiles; the way I understand it is newer USB power supplies offer a different range of voltage and current combinations, so 18 watts with one supply is not the same as 18 watts in another. I wonder if the HomePod mini never really needed 20w, just the 20w power profile and the firmware update simply allows it to use the 18w profile.

Well...  Watts (or power) is simply volts * current.  18 amps at 1 volt or 1 amp at 18 volts both equal 18 watts.  My understanding of the USB spec is that +5V is available (at different current ratings depending on the USB variant).  18 Watts at 5 Volts would be 3.6 amps.  Perhaps they wanted 20 watts to account for cable losses at higher currents.

As for the power requirement of the HomePod mini...  somebody would need to actually measure the current draw in a worst case scenario (likely maximum volume - probably with a lot of bass).  That said, what it requires is probably not 18 watts continuous.  It might not sound like much, but 18 watts without good heat dissipation adds up quickly and electronics do not like heat.  Those little 5 watt night light bulbs get wicked hot, and they are in a free air environment.

OctoMonkey said:

MplsP said:

crowley said:

That's cool that Apple was able to do this with a software update.

Agreed - I was reading in another (MagSafe duo?) thread about USB power profiles; the way I understand it is newer USB power supplies offer a different range of voltage and current combinations, so 18 watts with one supply is not the same as 18 watts in another. I wonder if the HomePod mini never really needed 20w, just the 20w power profile and the firmware update simply allows it to use the 18w profile.

Well...  Watts (or power) is simply volts * current.  18 amps at 1 volt or 1 amp at 18 volts both equal 18 watts.  My understanding of the USB spec is that +5V is available (at different current ratings depending on the USB variant).  18 Watts at 5 Volts would be 3.6 amps.  Perhaps they wanted 20 watts to account for cable losses at higher currents.

As for the power requirement of the HomePod mini...  somebody would need to actually measure the current draw in a worst case scenario (likely maximum volume - probably with a lot of bass).  That said, what it requires is probably not 18 watts continuous.  It might not sound like much, but 18 watts without good heat dissipation adds up quickly and electronics do not like heat.  Those little 5 watt night light bulbs get wicked hot, and they are in a free air environment.

Well, yes, watts is simply volts * current, there are different combinations and not all power supplies are capable of all the different combinations. The original USB Spec was for 5V; you're not going to run 20 amps through a USB cable to charge your laptop at 100 watts. 

USB Power delivery specifies profiles different voltages (5, 9, 15 or 20V) and different currents ranging from 0.5 - 20A. The  voltage is actually negotiated between the device and the supply. If the HomePod wasn't designed to work with an older version, it may not have been able to negotiate an appropriate voltage/current combination.