NRF52840 battery life estimation mathematical formula

[Usman Rashid]

Hi,

I want to know about mathematical formula to find / estimate the battery life of Bluetooth beacon containing NRF8240. If chip is transmitting at +8 dBm and have 1000 ms of broadcast interval.

[MartinBL]

It still depends on:

• Supply voltage
• Size of battery
• Number of bytes in packets
• What radio protocol you are using
• What physical layer you use (2Mbps, 1Mbps, or Coded phy).
• Whether you are using the DCDC converter.
• .....

In other words, it is next to impossible to estimate, and your best option is to make a prototype and measure the average current yourself. You can have a peek at this power calculator though. It is close to what you need, but note that it is made for nRF52832.

[Usman Rashid]

As I said, I want to estimate it not calculate.

This formula is for NRF52832 so it will not work for +8dBm TX power.

Do you know any mathematical formula to estimate it ?

[Usman Rashid]

Could you explain simply that what is DCDC converter use for? and what is difference if we use it or not use it ?

what do you meant by radio protocol?

[MartinBL]

As I mentioned, it is impossible to give an estimate based on only the two parameters you have given.

There are two types of voltage converters in the nRF52; Linear Dropout converters and DC-to-DC converters. DCDC converters are usually more power efficient, but requires additional external components (making your device slightly larger and more expensive). Here is more documentation.

By radio protocol I mean whether you are using BLE, 802.15.4, etc.

[Usman Rashid]

Does it works for NRF52840 FOR +4 dBm TX power

[MartinBL]

Does what work? DCDC works on nRF52840 in TX power configuration.