increase Button batteries CR2450 life

[zcmm]

hi,all
       my device use CR2450 button battery,advertise time 500ms 

TX POWER:4dbm,the battery life is low if it still use this configuration (May be big current lead to the battery internal resistance,so the 17ma can not work ). How to increase battery life,and do not affect the power consumption??

[Jørgen Holmefjord]

Hi,

Which chip are your device using? Have you done any current measurements? How long is the battery life?

For nRF52832, you can use the Online Power Profiler to calculate the expected current consumption. If your device is a beacon (only advertising), and you use the settings you mention (500 ms advertising interval, 4 dBm output power, and 3 V battery), your device should have a total average current consumption of 35 uA, even with full 31 bytes payload. Assuming your CR2450 battery have a capacity of 620 mAh, this should give a battery life of roughly 2 years.

If you get way shorter battery life than this, you might have something running in you application consuming excessive current. You should go through the current consumpiton guide (written for nRF51, but most of the consepts is valid for nRF52 as well), to fix potential issues.

Best regards,

Jørgen

[zcmm]

100ms 4dbm LDO 51822 TX POWER is 18ma standby current 3.7ua,just it advertising,it use 22 days for CR2450(550MAH)

[Jørgen Holmefjord]

Those settings should give an average current consumption of 2-300 µA, depending on your payload, or ~75-115 days with your battery capacity. If you don't have any current measurement equipment available, I would recommend that you get our power profiler kit, which can be used for power measurements in real-time and debugging current issues in your application. Then go through the link I posted above and see if you can figure out where the excessive current is drawn.

[zcmm]

average consumption is 60ua,i think the battery capacity utilization rate is according to the load current rather than the average current, if the big load current can reduce the use of capacitance

[Jørgen Holmefjord]

I see, you can get some tips to improve battery lifetime in this blog post. If you want to decrease the peak currents, you will have to reduce the output power and/or add DC/DC converter to your board. The radio of nRF52832 can also give lower current consumption, especially when using DC/DC.