I bought a couple of these Pocket32 V2. Nice idea to include battery holder attached to board. Actually, I had one holder come unattached at the + end. I re-soldered easily. No problem for me. However, I wish a battery voltage resistor divider to a analog input was included on the board. I would guess most folks who would buy this would want to be able to read the battery voltage. And with the ESP32 there are certainly enough analog pins. I can build my own resister divider and the software is easy, but it doesn't appear the battery voltage is brought out to an accessible header pin. Please inform me of the easiest hardware connection methods to measure 18650 battery voltage.

Update 5 Sep 2017. After using the Pocket32 V2 board a little more, I have some additional comments which may be of interest to other folks considering this board for battery-powered purposes. First the good news. The seller seems to be very prompt in responding to my comments, both here and via private email. I believe he is very interested in customer comments and improving his products. Also good to know, both of my boards have the latest rev1 silicon for the ESP32 chip. This fixes several issues with the original rev0 silicon.

And now the bad news. If you want to use this board for long-term battery powered applications using the deep-sleep function of the ESP32, you will likely be disappointed. My measurements indicate 15mA from the battery during deep-sleep. (Note this is with rev1 silicon and Arduino IDE fixes for deep-sleep.) The ESP32 alone should only draw around 10 micro-amps during deep-sleep, not milli-amps. The seller believes the main reason is the charging system. The board uses a TP5410 which is a boost regulator which works something like this: 3.7V from 18650 battery --> TP5410 boost to 5V ---> regulated down to 3.3V for devices on the board. Further research on the internet tells me designs using this TP5410 are not meant for lengthy stand-alone battery use. Much too power inefficient. The board will be fine if constantly connected to USB for power and then 18650 will be the auto backup supply. Also, as I stated before, it doesn’t help that there is no way to programmatically monitor the actual battery voltage on this board.