Hi all what battery I need in order to keep the electric imp connected to wifi network for a year ?
I need to send data to server each ten minutes and after that enter into deep sleep.
If you actually need to stay on WiFi and connected all the time, then you need something like 20 D-sized batteries.
If you are deep sleeping and waking up every 10 minutes, collecting data quickly and then turning on WiFi and going back to sleep, you should be able to do it with 2 AA batteries. The back of the envelop calculations are 6 Wakes/Hour * 24 Hours/Day * 365 Days/Year = 52560 Wakes per year. That math doesn’t take into account the power used when sleeping, but if you are careful with that design and keep it to 10’s of µAs then that power is quite small.
On the Nora design with 2 AAs we were able to get 60,000 wakes and the connection process has been improved since so it’s likely you could get more than that.
https://electricimp.com/docs/hardware/resources/reference-designs/nora/
You will need to be very careful about the software as well as the hardware to never stay on longer than necessary. If you don’t feel very confident then I would recommend 4xAAs as that should give you plenty of head room.
If you are just data logging and don’t need real time results you can also write your code so that it collects the data in NV ram without turning on the WiFi and only sends it once an hour, which would get you close to 6 times the battery life!