RB433 fan & DC/DC converter

Hi,
I’ve some RB433 and I want to add a couple of fan inside the boxes.
Actually I’m using 24v so I want to use the unregulated fan connector with a dc/dc converter to power at low speed the fan

in 24v → out ~8-10 v.

Is there any drawback in this setup?

As I can see the dc/dc converted have a little spike in term of power consumption when it starts …can it damage the board?

thank you
xm