The DC supply current gove up with power and load mis-match. Typicial current draw
at 10W is about 2A give or take. At 80M without mods it tend to run 12-15W and a bit
As you go up in frequency the power out drops so the current well as well. High SWR will
increase current drawn at any power out.
I'd not use a supply less that 4A. I'd also not use an antenna over 2:1 SWR.