How long does nRF52832 work normally when using button cell powering for nRF52832 ?

[tianfei00]

Dear all,

     I remembered that nRF52832 can be powered with button cell, for example CR2450, and worked normally more than 1 year in Nordic website. But now I can not find the message again. So I want to know how long does nRF52832 work normally when only using button cell powering for nRF52832 ?

    In my project, I using CR2450 powered for nRF52832, and only do few things which when I pushed one button , it will send message to smartphone. But I find the connectivity is not stabilized. Sometimes nRF52832 will  always initiate to terminate connect with smartphone. However when I use external power for nRF52832, this phenomenon will never take place.

    So, I doubt  whether  button cell can not power for nRF52832 ?  Because the connectivity of bluetooth is not stabilized.

   I will look forward your guidance.

  Thanks very much.

[AmbystomaLabs]

It sounds like you have failed to put together a power usage plan for your product. You should review the CR battery specifications and you will find most are rated for 1mA maximum.  Yes, only 1mA at any one time.  Since the nRF like most all BLE SoC's uses about 10mA during TX/RX you have to do the engineering to make sure the local storage is sufficient (ie, caps) and the duty cycle is low enough (ie, your code) such that 1mA max is never exceeded.  If you don't do this work nRF_Vdd will drop during TX/RX and you will have erratic radio behavior, disconnects and even brown out events.

[tianfei00]

Hi,

    You are right and I do a test and find the CR2450 can output 15mA for several seconds.

[AmbystomaLabs]

You should not do that. If you design for that you will substantially reduce the battery life.  You have to design for max 1mA.  Even that will reduce the battery life.  Nominal life is achieved with 0.4mA max.

See the datasheet: http://data.energizer.com/pdfs/cr2450.pdf