Subj : Re: pi5 psu?
To   : All
From : Pancho
Date : Mon Oct 13 2025 18:20:41

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.

--- PyGate Linux v1.0
 * Origin: Dragon's Lair, PyGate NNTP<>Fido Gate (3:633/10)

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