[Elecraft] K3 - How much supply voltage is too much?

[Ross Primrose N4RP]

I have a surplus laptop switching supply that's 15V @ 5A. Is that too 
high a voltage to run my 10W K3 on routinely?

Thanks, and 73, Ross N4RP

-- 
FCC Section 97.313(a) “At all times, an amateur station must use the minimum transmitter power necessary to carry out the desired communications.”