One of the big issues I have with very cheap power supplies are that they
leave vital parts out of them to stop radio interference and to protect
things if the device malfunctions.
Several people I know bought a 5v usb psu from a now defunct supplier,
which had all the right markings but the top cover was held on by screws
that were about as good as those in a cassette housing, just two of them.
Some simple cam apart exposing live connections while others due to the poor
internal protection melted in use as there was nothing to stop it if a
component failed. Even worse during such a fault it could trash an expensive
phone in the process.
This is one reason why I'm extremely reluctant to fit mains sockets with
usb chargers in them, who knows what the quality of the modules inside is?
Brian

--
----- --
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...

Blind user, so no pictures please
Note this Signature is meaningless.!
"Nick Odell" wrote in message
...
On Mon, 25 Nov 2019 03:37:03 +0000, Bill Wright
wrote:

Prices for a 33V 1A psu as used by stairlifts to charge the battery.

Typical Amazon price: £18
Farnell: £26
Medical grade item: £76
Quoted by a stairlift supplier when a replacement was needed: £181. Item
is tiny and in a plastic case, and appears to be poor quality.


Between £2-£3 on Ali-Baba, minimum order 1pc, computer mains plug type
input, co-ax plug output.

https://www.alibaba.com/product-deta...fb6b2a1c9YPc6X

Mind you, it could burn your house down as soon as you switch it on.
But then again, it might not.

Nick