ESP8266 Community Forum

- Sun Aug 16, 2015 5:06 pm #26217 Hey,

I'm designing a board with an ESP8266. I'm developing a wearable device with space constraints; I need a really small battery to power the module: < 90mAh. I only need an autonomy of ~3hr to 6hr. The application sends really small packets (no streaming at all)

I would like to know if some of you already made a project with small battery and if you experienced problem like:
-Battery cannot flow enough current to the module
-Intermittent disconnection
-Smaller range

My second question is, what kind of decoupling capacitor you use? I cannot choose a big capacitor with high voltage. You think a ceramic 10uF 16V capacitor is well enough to handle these 300mA peaks?

Thank you for sharing your experiences!

Alex

- Mon Aug 17, 2015 9:34 am #26270 Consider using bluetooth or use sleep mode for the ESP8266. A small LiPo battery should be able to provide enough current (200-600mAh).

- Mon Aug 17, 2015 11:45 am #26278 Thank you for your answer.

Battery life is not a big issue since the devices won't be used during a long period of time (almost on the charger all time)
We need to connect 6 devices at the same time to a server. It's tricky to manage 6 Bluetooth devices at the same time on a mobile device!

Best,

Alex

- Mon Aug 17, 2015 6:50 pm #26302 In my experience, LiFePO4 is the best battery tech for this... see my test rig that goes for hours:
https://www.hackster.io/rayburne/warwalking

Also, LiFePO4 is reasonably safe, Li metal never occurs in the charge/discharge cycle. The 3.3V cell can be charged to approx 80% of capacity by floating on 3.3V. I'm floating mine at 3.45V and the ESP8266 is happy.

Ray