From: news@cct-net.co.uk   
      
   On 13/10/2025 18:32, Chris Townley wrote:   
   > On 13/10/2025 18:20, Pancho wrote:   
   >> On 10/12/25 16:03, Daniel James wrote:   
   >>> On 09/10/2025 16:42, Mike Scott wrote:   
   >>>> I've just installed rasp OS on a new pi5 for the first time. It   
   >>>> moans the psu is insufficient, and can't deliver 5A. But the psu   
   >>>> itself - a kosher raspberry pi one - claims it will deliver 5A/25W.   
   >>>   
   >>> That doesn't sound right.   
   >>>   
   >>> Raspberry Pi sell three different USB-C PSUs:   
   >>>   
   >>> - A 15W PSU for use with the Pi 4/400 only.   
   >>> - A 27W PSU for use with the Pi5/500 (and 4/400)   
   >>> - A 45W PSU which is like the 27W but more powerful and can power   
   >>> some laptops, etc.   
   >>>   
   >>> The 27W and 45W PSUs support the USB Power Delivery spec and will   
   >>> provide a range of powers/voltages after negotiation with the device.   
   >>> The 15W PSU provides only 5V/3A, and is stated to be inadequate for   
   >>> the Pi5 and later.   
   >>>   
   >>> There is no official "kosher" 25W PSU from Raspberry Pi.   
   >>>   
   >>   
   >> I think the 27W PSU was the original official version.   
   >>   
   >> Also, it is worth making clear the rPi5 USB PD is unusual, it only   
   >> uses 5V and negotiates current up to 5A (which somehow = 27W).   
   >>   
   >>   
   >> Whereas my normal USB PD plugs produce their specified high wattage by   
   >> boosting voltage, so they don't work with the rpi5 at all. Which   
   >> irritated me a lot when I found out.   
   >   
   > ISTR it can give other voltages, but the Pi5 will only negotiate 5V - or   
   > 5.1V I believe   
      
    From the spec: The available profiles are 9V, 3A; 12V, 2.25A; and 15V,   
   1.8A, all limited to a maximum of 27W   
   See https://www.raspberrypi.com/products/27w-power-supply/   
      
      
   --   
   Chris   
      
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