Hi, I just wanted to say thanks for the valuable information on the PMIC and its use in the t-beam.
My use case is something completely different, but it helped a lot solving it.
I’m combining a t-beam with a pi zero W in a prototype (portable networked camera) and thus need to power the Pi and the t-beam from the battery. The pi needs 5V, but the 5V pin on the t-beam is VBAT as written in another thread (TTGO TBeam: Off-board USB? - #5 by dafeman) and therefore is not usable to power the Pi, especially if battery gets emptier.
So I soldered an external DC/DC buck converter (like those found in powerbanks) parallell to the t-beam and use that to power the pi.
To communicate with the t-beam, I connect it to the Pi’s USB host port. This worked well, but the DC/DC converter got very hot, basically because I fabricated a “charging loop”.
Adding
axp.enableChargeing(false);
to the t-beam firmware should fix the loop. That was actually what I was looking for, I’m still able to read out battery voltage and other info through the PMIC. The other solution would have been to physically disconnect the battery from the t-beam.