Big ESP32 + SX127x topic part 2

LoRaTracker · September 9, 2018, 9:41am

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

disp.ssd1306_command(SSD1306_DISPLAYOFF);

Takes less than 1uA in this mode.

admiral99 · September 9, 2018, 10:28am

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 · September 9, 2018, 10:53am

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

admiral99 · September 10, 2018, 9:30am

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.

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 · September 10, 2018, 5:11pm

Hi
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 : https://github.com/ngraziano/lmicesp32

I test it on Heltec board in EU868.

Verkehrsrot · September 10, 2018, 9:27pm

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 · September 10, 2018, 9:45pm

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…

admiral99 · September 11, 2018, 9:29pm

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.

20180911_232253 20180911_232222

alvarnal · September 11, 2018, 9:46pm

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?

Lennyz1988 · September 14, 2018, 8:34am

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 · September 18, 2018, 1:04am

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.

Thanks

admiral99 · September 18, 2018, 1:46pm

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

gregorwolf · September 23, 2018, 3:46pm

I’ve also got the TTGO ESP32 V2 1.6 unfortunately still can’t see the design on Thingiverse. Can you check if you’ve published publicly?

jwijngaard · September 23, 2018, 7:24pm

If you now following the link, you got the view off a nice case.

https://www.thingiverse.com/thing:3098676

Verkehrsrot · September 23, 2018, 9:23pm

Be careful with connecting a battery, did you see the warnings above?

Verkehrsrot · September 23, 2018, 9:26pm

In the TTGO v1.6 design power from USB and battery runs over a diode (at least it should, when the did not accidently used a fuse). That means that we give about 0,1 Watt of power at this early point in heat, even before it arrives at any circuit…

ElectronicallyE · September 26, 2018, 5:39am

Hi all,

Been trying to use a 18650 rechargeable lithium ion battery with my TTGO ESP32 SX1276 microcontroller and not having much luck. TTGO does not seem to want to be powered by the battery.

From my understanding I thought that if you plug in the TTGO via micro USB it simply charged the battery and you are good to go, but it doesn’t seem to be the case with my testing.

Has anyone had any experience with powering this board using a battery? If so, could you please tell me what you had to do to get it working.

Thanks in advance.

Attached below are photos showing my setup for reference:

alvarnal · September 26, 2018, 7:59pm

to lower the consumption it is necessary to review the hardware very well, to be able to lower the consumptions.

arjanvanb · September 26, 2018, 8:42pm

Which version of the board are you using? Beware:

ElectronicallyE · September 26, 2018, 10:04pm

My board isn’t the 1.6v-v2.1. It has no indication of the model on it. The link I supplied above shows a board identical to mine, excluding the OLED.

I’ll try charging the battery again to see if I didn’t charge it long enough. How long do I need to leave it for if I do so?