Greetings! I got started with Meshtastic a few months ago and am having fun learning. I found an old thread on this topic from 2022 but decided to start a new one instead of reviving that one.
BLUF, I have powered a T-beam externally through the 5V and GND pins and everything mostly seems to work. No 18650 is installed and the USB is disconnected.
So far the options I have come up with for externally powering the T-beam include:
- solder power wires to 18650 terminals, apply 4.4-5V
- use USB power (I prefer not to do this so I can keep the USB connected to an external bulkhead for comm and reprogramming)
- apply 5V directly to 5V Pin on T-beam
- apply 5V to VBUS0 line if I can find a suitable entry point on the PCB
Of these, I have attempted the third option (5V to 5V pin) but both the old thread and the AXP2101 datasheet suggest that this is not the right way to do this. However, with no battery installed, and no USB connected, the T-beam appears to work. Or, it does work, my external regulator is not overheating, the 2101 does not seem to be overheating, etc.
The reason I’m using external power is because I have the T-beam integrated into a larger system with big batteries and a separate microcontroller, and I have ample regulated 5V available (just prefer not to feed it via the USB, if at all possible). This is also why I don’t need to include the 18650.
Pitfalls with doing it this way? Thanks for any advice!