Hi there!
yeah heat and electronics (any electronics) is bad. Running in blazing summer heat is a problem I've also faced for a while and I have something that works so I'll pass it on.
The exact configuration varies with what I'm doing (rolling road cases, small two-channel taper rig), but the principles are the same.
I run with a v3 which of course sheds heat through its aluminum case acting as a heat sink, thus doubling up on the heating up the situation.
My solution is to place the v3 above the deck so its heat leaves the bag without heating the deck. Simple idea, helps a lot.
Then make sure that there is room for air to flow vertically so the heat can dissipate. (cooler air in the bottom, hot air out the top)
The big one I really got working well this year is to use a reflective emergency blanket to keep the sun off the bag.
(Not a loud and krinkly one, but one that's silent and more tarp-like, still cheap!)
Set it up so it still allows vertical air movement and it makes a fantastic difference in keeping the heat off the gear.
For the first time my deck ran cool to the touch in blazing heat..
(even a silver umbrella would work well for this I think.)
Highly recommended and I don't leave home without it. Plus it'll keep rain off in a pinch.
-Cheers!