ESP8266 Community Forum

- Sun Nov 08, 2015 3:58 am #33424 Hi,

this is my first post on ESP8266 Community Forum

I am also just starting with arduino and ESP8266 module. I have managed to do a simple weather project.
The thing is that my ESP is powered with MB102 on my breadboard. MB102 provides 3.3V to ESP.

My goal right now is to replace MB102 with some other power choice. I was thinking about AA batteries but here i have a problem which i hope u would help me solve it.

1) ESP needs 3.3V

My rechargeable battery AA has label with this data: 1.2V - 2500mAh
I have recharge it and measure it with my multimeter: 1.3V

If i put:
2) 2xAA i get 2.6V but ESP needs 3.3V
3) 3xAA i get 3.9V or a little more but this is much more than ESP needs

Should i use 2 or 3 AA?
Are 3 of them gonna damage my ESP?

- Sun Nov 08, 2015 4:10 pm #33483 Hi mojESP8266,

According to the datasheet the voltage should be in the range of 3.0-3.6V though some people at the makehackvoid forum did some testing and managed to get the ESP8266 working with voltages around 2.3-4.7V.
(http://forum.makehackvoid.com/t/esp8266 ... urrent/286)

Two batteries would most likely work and it seems 3 batteries will most likely not destroy your ESP, no guarantees though.

- Sun Nov 08, 2015 6:31 pm #33498 I ran the esp on 3xAA and it is just fine, but not efficient as the current used rises fast when you go above 3.3v. 3xAA start at around 4.5v and drop fast initially. They die around 1v/cell.

My experience is about 60 days on 3xAA when waking up from deep sleep once a minute. Reading a ds18b20 and sending a UDP packet takes 600-700ms.

If the intent is to get a long run then you need to use a suitable LDO (I use an MCP1700 which is very efficient at Iq=1.5uA, and can handle the intermittent high current despite the spec of 250mA). The common AS1117 often has very high Iq, measured in mA. You also should use low self-discharge batteries, if not move to different chemistry altogether.

Which module do you use? The small ones (esp-07 with 512KB) is significantly more efficient. esp-12 (usually 4MB) I could configure to be fast by building the fw with FLASH_512K instead of AUTOSIZE. But does you app fit in the smaller flash?

I plan to experiment with different build options in `user_config.h` to see how they affect performance.

- Sun Nov 08, 2015 6:37 pm #33499 Hi, not cheap but this is a great little device - you can use a wide range of voltages (2.7V -> 11.8V) - so charged or nearly flat cells still work - ideal if you want to charge a cell whilst still connected to the ESP - good with solar topup to.
https://www.pololu.com/product/2122