Hello! I'm creating a device where the battery replacement is an issue. The device is a temperature sensor, a SAML21 uC and a Sigfox module.
The uC wakes every n seconds, measure the temperature and send data if some conditions are met (about 10 reports per day). Then, it goes to sleep again.
Most of the time, the device consumption is no more than 50microamps, but when there is something to send, there are 3 burst of 200mA (sigfox). When there is something to send, I enable the 3.3V regulator of the comm module, send, then power off the module and the 3v3 regulator.
I expect some voltage drop in the battery when the module is transmitting. If the votage drop is between the allowed voltage of the microcontroller (1.8~3.6v), is it safe to power the uC directly from the batteries?