Pierre,
I use the 10W linear PA with the Hermes LIte 2 and get 10W out with 13.8V VDC.
As Allison explained, you have to take care of the TX/RX switching as the amplifier does not have this functionality.
With the HL2 and the low power port there is a caveat.?You have to TX and RX in different antenas. I use this setup in low bands. TX is via the HL2 low power port into a dipole and RX is via a separate receive antenna.
The alternative is to build/buy a RX/TX switch, attenuators and all that jazz....
You might find this useful.?
73 Angel
M0HDF