I have a new bike computer but haven’t raced with it yet. If I turn it on before my race will it acquire the GPS satellites and then go to sleep? Or do I need to actually turn on the power during my bike split and wait for it to cycle on? I’m hoping the former but need to find out either way.
I have the Wahoo Element Bolt. I changed the Auto-Off to 2 hours, and turned it on and set it up before swim start (gave the crank a spin to activate my Power Meter). Then when I got the bike to the mount line I just hit start and off I went.
It even found my HRM when I got back within range of the bike.
I didn’t shut computer off when I got to my bike after the race, so Wahoo shows me with 5+ hours of “cafe time” 
The bolt was on for 10:35, and the battery was at 11% when I shut it down.
Thanks for that info. That’s exactly what I needed to know!