How to power an ESP8266 from a single LiIon Cell

[theelectronicegg.com]

I want to run some ESP8266 chips from single Cell LiIon batteries. Fully charged they have a Voltage of 4.2 / 4.1 Volt. The protected Typ will run down to 2.5 Volt. So my Input Voltage is 2.5 to 4.2V.
The ESP8266 has an input voltage of 2.5 to 3.6 Volt.

I have tried two Options:
a) connect battery direct to esp8266. Advantage: Working down to 2.5V cell voltage. Disadvantage: stressing esp8266 with 4.1 Volt. it is currently working, but its not a nice solution.
b) using a LM1117 voltage regulator. Works fine with an input of 4 Volt and down to input voltage of 3.5 V, still producing an output voltage of 2.5V. Advantage: Keeping the ESP8266 in spec. Disadvantage: stops working at a cell voltage of 3.5V

Before i try different switch mode power supply options, I would like to have some input on other real world solutions. All the tutorials have some sort of 5V usb power source.
i would like to optimize for battery life. The ESP8266 wakes up, reads a sensor, sends the data over WIFI and enters deep sleep for 5 minutes.

[kripton2035]

[thm_w]

Dropout of LM1117 is 1.1-1.2V at 500mA, which is really high.

At 300mA:
MIC5504 160-380mV
LT1763 250mV
AP7361C 100mV

Quiescent for these is 30-60uA. You can get buck regulators in a similar range, it just depends on the cost and complexity you are willing to deal with.
Just have to be careful that they are capable of peak current required (or have suitable output capacitance). Or use the lifepo as suggested by kripton.

[julian1]

I have powered esp8266 with LiFePO4 batteries without a linear regulator. The advantage over lipo is lower voltage drop over the discharge range, safer, and simpler charge regime.

[ivaylo]

Not sure it's exactly what you are asking, but this board had been good to me - https://www.sparkfun.com/products/13231 Schematics is also available...

[ebclr]

With few dollars, you have this solution



http://pt.aliexpress.com/item/18650-Battery-shield-V3-for-arduino-Raspberry-Pi/32815139060.html?spm=2114.02010208.3.10.JtXNMe&ws_ab_test=searchweb0_0,searchweb201602_2_10152_10065_10151_10068_5010019_10136_10137_10060_10138_10155_10062_437_10154_10056_10055_10054_10059_303_100031_10099_10103_10102_10096_10052_10053_10142_10107_10050_10051_10173_10084_10083_10119_10080_10082_10081_10110_519_10111_10112_10113_10114_10182_10078_10079_5030020_10073_10123_10120_10189_142,searchweb201603_9,ppcSwitch_5&btsid=35e4ab3d-9172-4f2e-9813-f119ff23de2a&algo_expid=ec59ef5f-4bea-4246-8f1f-13b4a2eb5f79-1&algo_pvid=ec59ef5f-4bea-4246-8f1f-13b4a2eb5f79

[theelectronicegg.com]

Thank you.

I will evaluate these options next week.