The 9v batteries i tested only lasted just over 14 hours and stopped working as the voltage dropped down to 6v. 1V over 5V for the 2 stage 5v, 3.3v Open Smart module voltage regulators
Then i used a 3.3v low dropout voltage regulator directly and it also lasted just over 14 hours
So i could not get to use the rated 800mAh life of these batteries (possibly wrongly rated)
Next i will use 2 x LiPo18650 batteries in series
Just waiting for some battery holder’s