CR2032 coin cell capacity measurement

[Lalit Kumar Baghel]

I am developing a device based on STM32L412KBT6 powered by CR2032 coin cell.

I am planning to display coin cell status on a LCD display. For measuring coin cell capacity i am planning to use Fuel gauge/Coulomb meter.  

Since the device is working on coin cell so is it a good practice to use fuel gauge ?

If not, then what are other possible options for coin cell status measurement keeping in mind the ultra low power application.

[Vangelis Fortounas]

Hello

IMO voltage measurement in these small non rechargeable cells gives better image about the charge state of cell than basing on a charge measurement that implies knowing the initial charge (big margins between chn cheap coins and others, fresh and old ones).

PVD, ADC and some precautions, about maximum current provided by cell in different charge states, combined together give cheaper and less complex system

[Lalit Kumar Baghel]

​Hii

Can you please elaborate in detail?​

[Uwe Bonnes]

Charge measurement require constant measurement and so high current consumption. Voltage measurement can be done with low frequency.

[Lalit Kumar Baghel]

Thanks Uwe, you mean monitoring coin cell battery voltage on ADC and displaying a bar graph accordingly right?

​

​

​

[Uwe Bonnes]

I tried to say that a I suspect a coulomb meter on a CR2032 will have great impact on the current available for the real task. How to display is another question. Display e.g. on a power hungry display would also contradict the real task.