I've made essentially the same comments over several years
on the LT, ADVRider, and now GTL forums.
Here's the latest thread on how to make the heat irrelevant:
Spent the last three days riding in VA and NC*
where the heat indexes were in the 105-115 degrees.
Fayetteville, NC to Alexandria and back on Friday.
Left at 0300.
Got home at 2230.
Saturday, left at 1000 for Raleigh to change the rear tire.
Got back at 1530.
Left at 0730, this morning for a breakfast ride.
Returned at 1430.
Since I purchased my Veskimo personal cooling system five summers ago,
I'm more worried about the bike overheating than myself.
The intense heat adds one, maybe two recharges of ice on a long day trip.
Otherwise, the heat and humidity aren't factors.
12V power isn't an issue, either.
I carry a lithium-ion battery pack and AA batteries, as back up power.