While the NFC functions don't need a battery the actual glucose monitoring side and the storing of 8 hours worth of data would need a power source.
I haven't opened a recent sensor, but the early sensors did contain a slim watch battery.
I might have to take my latest sensor to pieces now just to have look, but not for another 13 days as only activated yesterday.
Last edited by caryh; 15th Sep 2016 at 13:28.
Reason: More information