Double-check your pinout and your keys.
Pinout of TTGO-Tbeam can be found here:
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i’m not sure if this is the right place to post my question about TTGO T beam. It’s my first ESP board and my very first project with ESP and lora. my question is simple, can i use my board without battery, just power it on using only USB (connected to PC). I already tried that because i though it’s fine, like almost every single board in the market has an USB port for power and programming, but the moment i turn the switch on i heard some noise.i’m not sure if the noise is from Lora component or not but i think it is, so i just turned off.
why not
“why not”
it’s the same though i had in mind when i was buying the board. if i can charge the battery from usb it means the usb can power the system on, which mean no need for battery if i want to work inside. but as i said, when i tried that, i heard some noise. (like a charger when it makes a low noise. i don’t know if you heard that before or not) but not a loud noise just noticeable.
interesting… and does it work 
The noise goes away as soon as you put a rechargeable 18650 battery in.
Same here.
what component makes that noise… inductor ?
A switching power supply may make some sound if the load is too low, as the switching frequency may drop. I’d just put a battery in it, there’s no good reason not to do so that I can think of.
the sound was from the LORA component. and using a battery as a solution, the thing is, i need time to go and buy it. (i can’t just order it online and electronic shops are not close 
) and i want to test the board as soon as possible. if the sound is not an indication or warning for any problem then i can work with it. i just don’t want to see my board get in fire.
The sound ist not from the LoRa chip imho, and with battery connected it reappears as soon as the battery is fully charged.
so, what causes that sound? and is it safe to work without battery?
The sound would be caused by an inductor in the charging circuit, as when the battery is not present or fully charged the voltage sensing circuit would read a higher voltage and start reducing the duty cycle to the switching transistor. That is the source of the sound you hear.
Thank you for the explanation. and can that cause any damage?
Hello,
I have a question about the battery duration in your tracker.
On my side with this devices, I was not able to have more than 35Hours.
Did you manage in getting several days of power?
Which code did you use for low power optimisation?
never got more than 5hrs use out of it
I have just purchased three of these. And programmed them to use softRF to send gps coordinates to each other to display on the oled screens. As part of the data packet i have used the ESP serial number as the packet sender id. Each device repeats a received packet once to increase point to point range between devices. I also receive what looks like Lorawan packets from time to time. And my devices also repeat that as well. Does this mess with the Lora network? My plan is to create a mesh repeater system for gps and data transfer. Would i be better off abandoning the design and concentrating on Lorawan or have my implementation running along side Lorawan within each module if that’s possibe?
That’s up to you, but creating a lora mesh system is out of the scope of this board.
Perhaps tagging ‘your’ networks packets is a good idea. Then you can avoid repeating foreign packets.
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