I think he used white glue.
I had been monitoring my under hood temps when I had my belly pan, side skirts, and grill block in place. During the winter months, my under hood temps were in the 170°F range. During the summer months, those have rocketed to over 240°F.
So far my new (1.5yrs old) battery has worked just fine. My alternator died (it wasn't the brushes) one day...so I had to replace it. Not sure if the extended heat is hardening the rubber valve cover gaskets or not...but they are starting to weep. I'm gonna have to revise how my engine bay is gonna git vented in my next generation.