Will this function as a PSU?

[ruudxd]

Depends a bit on what you want to charge.
You will not be able to charge at the chargers full potential (250 watt ) since the power supply can only provide a maximum of 120 watt ( 10a*12v= 120 watt ).
I do not know about this charger, but most chargers work better at a higher voltage input when charging higer cell counts.
I use a server power supply, something like this:

https://www.ebay.com.au/itm/HP-DL360...rzPg:rk:9:pf:0

There are some topics on this forum and other ones on what you need to do to use them as a power supply for an RC charger.
This differs a bit from type to type but you should be able to find some.
I used this link:

https://www.rc-help.com/ams/1000w-po...e-powerful.37/

If I am able to do this, then you are to, I suck with eletronics :-)