We are trying to integrate a water level sensor with electron. Electron wakes up from sleep mode once every 15 minutes. Only one power supply can be given (either at Vin or Li+). We want to maximize the life of the instrument. We have 3 questions:
I have seen that BQ24195 has lots of features in-built. I want to work with as minimum of them as possible and make a minimum quiescent current. Does the default sleep mode function (SLEEP_MODE_SOFTPOWEROFF) offer the lowest possible quiescent current from BQ2415? That is, is there possibility that I can modify the system firmware to make the quiescent current even lower?
Where do you advice us to connect the power supply to (Vin or Li+)? We are thinking of using LiSOCl2 batteries (each is 3.6V, hence voltages in multiples of 3.6V).
Finally, can you tell us the sequence of routines the sleep mode is doing to make electron consume low power in sleep mode?
I’m pretty sure the BQ24195 is in the lowest power mode in SLEEP_MODE_DEEP or SLEEP_MODE_SOFTPOWEROFF however there are so many settings I can’t guarantee that.
(SLEEP_MODE_SOFTPOWEROFF is SLEEP_MODE_DEEP but also turns off the MAX17043 fuel gauge.)
You will definitely get the lowest power consumption using Li+, assuming you can provide an acceptable voltage level. The reason is that when powering by VIN the voltage regulator is always on. When LI+ is in an acceptable voltage range, the regulator can be bypassed. It’s only possible to get to 110 uA in deep sleep when powering from Li+.
This post may clear up some confusion about how to get into the lowest power mode, as various combinations of threading and system modes can prevent it from working properly: