I think at 10%, it's time to come home.
I don't trust the readings on the batteries as the usage is based on current power consumption and returning to home can take more than current.
I got my first heat exhaustion when I was 11 so it's not necessarily the getting old thing.
The sun, now, seems to hit a lot harder than it did 50 years ago, though. I'm not sure it's the personal age that's 100% responsible for that.
But...
I live in Kaufman County TX, East of Dallas. Pretty much all fireworks, including the big mortars, are legal. I grew up in Denver and watched all fireworks become illegal.
In spite of how loud it was, and how it scared my dogs and cats, I’m...