I don’t suggest retrofit the development board you have to be powered by a battery. If your project needs battery backup. Please consider getting a board with the backup battery feature designed on the board. This is one such board. 
https://www.amazon.com/Adafruit-HUZZAH32-ESP32-Feather-Board/dp/B01NCRYHDL/ref=sr_1_13?crid=SMTL63LRT79N&keywords=esp32+development+board&qid=1583553619&sprefix=esp32+%2Caps%2C342&sr=8-13
 

Hi sendemail2albert,

Thank you for your kind response.

I plan to make a smart water bottle prototype; therefore, I need the board to be powered by a battery and can be charged conveniently using cable for my field study.

Do you mind to explain more why you don’t suggest the board to be powered by a battery? How about if I use something like LiPo Rider Plus (https://www.seeedstudio.com/Lipo-Rider-Plus-p-4204.html)?

I have been seriously considering to buy either Adafruit HUZZAH32 or Sparkfun 32 things for a while, as they have the LiPo charger embedded in the board. Did you have experience using both boards? Do you have any preferences?

Hi.

Just to clarify. Is this the board that you’re using https://pt.banggood.com/ESP32-Azure-IoT-Kit-WIFI-BLE-ESP32-Development-Board-with-OLED-Buzzer-USB-p-1545719.html?cur_warehouse=CN?

If this is your board, on the documentation page 3/8 (https://www.espressif.com/sites/default/files/documentation/esp32-azure_iot_kit_hardware_design_guide__en.pdf)

It says:
“Besides, there is also a charge management IC on the board, so the USB port can also be used to charge the lithium battery”.

There are boards that have that feature built-in like the Adafruit HUZZAH32 or Sparkfun 32 thing. When powered through the USB cable, it recharges the batteries.

Regards,
Sara

HI Sara,

Thanks for your response,

That’s not my board. However, I think I got the point. Looking for the board with an integrated lipo charger is seems preferable.

Hi.
Yes, I think it is preferable to use a board with that feature built-in.
Just to clarify, can you post a link to the board you’re using? 
Let me know if you need something else.
Regards,
Sara

Hi,

I currently have two boards:
1. the (retired) WEMOS LOLIN 32
2. HiLetgo ESP32 OLED WIFI

I will order the Sparkfun ESP32 things in the near future.

Thank you very much.

best,
Bimo

Hello Agoeng,

Is your ESP32 board this one?

If you have the version with the ESP32-WROOM-32D…

…then you have a board that seems to be pretty close to the DoIt ESP32 DevKit (don’t know which version exactly… v1? v4? I’m a bit lost among what I’ve read here and there).

In any case, you’d better opt for a board that integrates a charging circuit such as the Adafruit HUZZAH32 (which is very good by the way, I have one). And you can refer to this guide for power management.

The SparkFun Thing Plus will be fine too, as confirmed by the corresponding guide.

Yes, a board has built-in LiPo charger integrated is the board that you need. Boards with LiPo charger circuits from China are cheap but most of them are questionable. 
Another area that you need to pay attention to is the connector. Make sure you get the right specification – JST1.25 for example. I suggest buying your battery from Amazon because you can return it easily if they are not the right connector. The last thing is that almost all battery packs are from China. The polarity of the connector may not be correct. The red wire should be positive and the black wire should be negative. Double-check this with a meter again the board before you plug the battery into the board! 

Great,

Thank you, everyone, for the advice, I will keep that in mind.

best,
Bimo