Go watch the second installment of the relay board build .
They have the Battery pad soldering holes as I suggested and work 100%
Lots of good info from a Hands on Tech with 20-years experience with seeed and in the LAB!
Nice walk thru of the work flow involved. 
GL 
PJ 
So , I missed the actual LIVE stream , But watched an Hour late, Any way I never saw them Solder the Battery Pad Holes on the bottom? Did you?
They like the recommendation in Part one , and even Opened Part Two with a few Comments and thank you’s. Pretty Awesome.
GL PJ
it was hard to see what they were doing…Ding Ding was soldering 6 pins at a time… and they didnt have a microscopic camera… it was amazing… dude had no question all his solder joints were good…
especially all the surface mount caps and resistors… even without tweezers
i learned the functionality of a blade tip on a soldering iron
its amazing what flux and proper heat application can do on the tech of soldering
Flux is your friend… Yea the Blade is key to multiple pins at once.
I saw them solder just didn’t see any of the bat pads specifically. 
He’s been with seeed for 3o yrs? WOW 
GL PJ
I used the hot air also…