Big ESP32 + SX127x topic part 2

(LoRaTracker) #813

You can put the SSD1306 to sleep when using the Adafruit library;


Takes less than 1uA in this mode.


Just tested using the adafruit library. Difference is very small. Power consumption only goes down to about 7mA. I wonder if the other peripherals can be put to sleep or shut down (e.g. RFM95 chip, SD card reader etc).

(LoRaTracker) #815

Make sure your SSD1306 is not the 5V type. The 3.3V ones do not have a regulator on the back.


I just received a warning from the TTGO (lilygo store) regarding their TTGO ESP32 Lora v2 1.6 with regards to charging LiPo’s via the 2.1 1.6 board.

:warning: Please all be careful. Message below:

Diode components should be used on the charging circuit.

We used a fuse. The diode is energized in one direction, but the fuse is bidirectional, which causing the USB voltage directly access to the battery.

After a long time charged, the battery is hot or burned, so please don’t use this V2.1-1.6 version to charge the battery! ! !

(Note: The board can be powered by battery, but we mustn’t charge the battery when the battery is connected to the board, mustn’t charge! mustn’t charge! mustn’t charge!)

If you want to use this V2.1-1.6 version to charge the battery, you need to replace the fuse in the picture with a diode, then the charging function return to be normal.

It can be changed the model number of the diode : BS5819 SOD123 / 1A current

(Grazy) #818

I just made an modified version of LMIC for ESP32.
It handle deep sleep between TX (by saving state to RTC RAM)
It use ESP AES functions and RTC clock.

If you are interested the code is here :

I test it on Heltec board in EU868.

(Verkehrsrot) #819

This seems to be a reaction to my post above, i forwarded it to Lilygo. That means my assumption battery has direct connection to 5V USB was validated by them.

Unfortunately another fatal design flaw and poor quality management seen at a chinese manufacturer…

(Verkehrsrot) #820

I received same mail today.
This is really dangerous. If i would have left the board with battery and USB connected unattended, my flat would probably had burned down. And i used a small 3Wh battery only. That’s far less than e.g. a common 18650 cell…


I’ve designed a small snap fit case for the ttgo V2 1.6. Some rough edges that I will clean tomorrow and then I’ll put it on thingiverse.


(Alvarnal) #822

good afternoon , i am trying to go down the ttgo v1 consume … in this moment i am in 8.7 ma ; i remove the leds license plate and the battery charger … someone Has anyone been able to lower this consumption?


I’ve published my simple case for the TTGO ESP32 V2 1.6 on thingiverse. Seems I have to wait 24hrs before the design is actually published as I’m a new user. Gives me some time to fix the TTN logo that is now upside down … :wink:

(Lennyz1988) #824

It won’t be possible because of the board design. See this post on github and the entire thread for more information about this:

They are talking about the Heltec version, but the same principle should apply to the TTGO.

(Alvarnal) #825

hi, in this moment i have a ttgo in 800 uA, i want to get down more; but the flash memory isn’t in sleep mode.



How have you come to that power consumption? Very interested!