# How long do Batteries last?

**URL:** <https://community.tempest.earth/t/how-long-do-batteries-last/523>\
**Category:** Tempest Owners\
**Created:** [March 6, 2018, 4:32pm UTC](https://community.tempest.earth/t/how-long-do-batteries-last/523 "2018-03-06T16:32:19Z")\
**Posts on this page:** 1\
**Showing post:** 30

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**Author:** ![eric](https://sea2.discourse-cdn.com/flex020/user_avatar/community.tempest.earth/eric/32/13553_2.png) [@eric](https://community.tempest.earth/u/eric)\
**Post date:** [January 31, 2019, 7:51pm UTC](https://community.tempest.earth/t/how-long-do-batteries-last/523/30 "2019-01-31T19:51:02Z")

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I’d say they are following usual pattern. The Air is going down slowly and that’s normal as it is using way less energy then the Sky …  
The sky typically dives at some point as you can see higher in this thread.  
Maybe winter period adds to a more acute drop as every battery is sensible to temperature.

I’d say, start buying a new set for the sky as it will last a bit more but will drop quickly once they go under 3V. Some hang on a few weeks or like mine, 1 week later and game over 🙂

here is a graph of typical behaviour of the Energizer

> [@Sky battery life](https://community.tempest.earth/t/sky-battery-life/2846/25):
>
> I agree this seems non-intuitive until you understand the discharge profile of the lithium batteries. It is nearly flat for a long time and then drops extremely quickly - the voltage output “falls off a cliff”. The point where the SKY stops operating is when enough of the batteries drop off the cliff, but they don’t all hit the cliff at the same point, thanks to normal variability in the batteries. So, your 0.5V batteries have already fallen off the cliff and the batteries that are just under 1…

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