Just out of curiosity, I checked my IC-718 that I use for portable operation. Receive current was about the same as my IC-7300 and was .82 amps. The transmit current in SSB was about 4.0 amps at 5 watts PEP...
...The largest current draw is on transmit and is not much more than a small QRP radio
The FT-818 list the receive current as .45 amps and the 5 watt transmit current at 2.7 amps. Not a lot is gained by using a strictly QRP radio other than size and wow factor...
It does, of course, depend a lot on your particular
application. My first QRP rig drew 450 mA... on
full transmit. My Argonaut was happy with a 1 amp
power supply. I have another rig that draws less
than 25 mA on receive.
A 4.5 Ah gel cell would run any of them for a full
day contest, or a week-long backpacking trip.
I certainly wouldn’t want to have to carry a
bigger battery (though lithium cells would be a
better choice these days).
That’s not to say that there is anything wrong
with using a high power rid at QRP levels.
But there are cases (such as when you have
to carry the station a significant distance) where
low current consumption is important for
minimizing weight. Of course, the weight of
the radio gets factored into that as well.