I think the shutdown time is personal choice. I left mine at 5 seconds so it cooresponds with the time is takes for my sony to shutoff and fold up.
The battery icon comes on when there is a power problem such as lack of power. I got it when i tried to power my sony deck and my empeg off them same power source in my dash. I guess that little wire just couldn't handle all the power, so i ran an 18GA wire from my battery to my empeg.

-Greg