Running for >1 year from coin cell

[JohnBrown]

I have read many times about how BT LE allows devices to run for more than a year on a coin cell. However, the least current consumption I can obtain while connected is around 60 - 65uA. This corresponds to more like 11 weeks(from a CR2032). So if I wanted, for example, to notify my smart phone when a reed switch on the front door is closed, how do I go about it? Do I have to make the nRF51822 wakeup, start advertising, get connected etc., or am I missing something?

[Locky]

If you are getting 60uA or 0.06mA, on a CR2032 battery (220mAhr) you should see 3666.667hrs or ~21.8weeks.

Based on your consumption measurements, I'd venture a guess that your Connection Interval is ~250msec. If you change your Connection Interval to 1 second your consumption should go down to ~0.02mA which under a simplified consumption model for CR2032 would last 65weeks.

Please note this is under ideal conditions, no disconnects, LEDs, button pushes or other leakages. Disconnects/Reconnects play a huge part in power consumption.

[kaku]

In your door monitor application, if you want to extend battery life I think need to extend connection interval and slave latency(which can skip to ask every connection interval for master device). Off course the important factor to consume depends on your LEDs, Button and device to monitor the door, etc. Thanks.

[JohnBrown]

Thanks. Don't know where I got the 120mAH figure from, just misremembered it, I think. I'll try extending the connection interval and see what I get.

[JohnBrown]

Thanks. The door monitor is just a hypothetical example. I understand that LEDs etc. have an impact!