PC fan on 30 volts

[Gustav]

I'm wondering if it might be possible to run one of the very slow 80mm fans on much higher voltage,some of the ultra quiet ones only spin 1800rpm on 12v.

Is this a very bad idea? I don't mind the fan dying,they're cheap,concern would be if it could short out and kill other stuff.i want a fan i can run straight off the main batteries from 4s to 8s.Are there some very small voltage regulators i could use instead.?