Poor battery life (less than 4.5hrs) and unreliable sensor connections

Today I set out to do a ride. Fully charged overnight. There is full sun on the device all day. 

Frequent Garmin Varia and Garmin HRM sensor disconnects. Of note, my Assioma pedals and Bontrager headlight never disconnected, just the garmin sensors.

4hrs and 27min into the ride, the 1040 tells me I should enable power saver mode. I enable it and it tells me that I have 3hrs remaining. 

15min later it was dead and wouldn't even turn on. So on one hand the battery life sucks badly. On the other, it totally lied about the remaining battery life. What happened to the amazing battery life advertised? Why cant it make reliable predictions? Thanks for leaving me in the middle of a ride with no radar. Arent safety features supposed to be reliable?

And in the next hour+ of riding in sunshine why wouldn't it collect enough energy to power back on? Does the solar actually do anything?

I know I know, you guys are going to jump to the defense of Garmin and highlight that calling the ugly baby ugly is rude and insensitive to their feelings and that I should be nicer about spending 700 dollars on a device that simply doesn't work reliably doing even the most basic things it is designed to do. 

I did the second half of my ride using strava on my phone, no thanks to garmin whatsoever. At least my iPhone works reliably.

Running 12.15 firmware fwiw.