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.

[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.