45W at 5V DC is 9A.
But the fact that you only have a wattage rating suggest it might be a USB PD charger. If so you'll only get 15W. To get 45W the source and sink need to negotiate a higher voltage and the 4B doesn't do that. If your servo(s) do you may end up putting that voltage into the Pi which will break it.
Next...
Current (A) is pulled not pushed. In the absence of a dead short the Pi will only pull what it needs regardless of what the PSU is rated for.
But the fact that you only have a wattage rating suggest it might be a USB PD charger. If so you'll only get 15W. To get 45W the source and sink need to negotiate a higher voltage and the 4B doesn't do that. If your servo(s) do you may end up putting that voltage into the Pi which will break it.
Next...
Current (A) is pulled not pushed. In the absence of a dead short the Pi will only pull what it needs regardless of what the PSU is rated for.
Statistics: Posted by thagrol — Fri Mar 28, 2025 11:59 am