Anybody know how the t-beam is supposed to work when in “router mode” (with installed battery) but being powered by the USB port from a solar source?
My expectation was that if the USB power source declined beyond a usable cut-off, it would revert to using the onboard battery until that was depleted, but still in router mode. If USB supply resumed, it would use that as the power source and if sufficient, also charge the onboard battery.
That is not what I seem to be seeing happen. In my experiments, once the solar source diminishes enough, the t-beam seems to be shutoff, not running on its battery.
My ideal scanario is that I use a solar USB source to power and charge the t-beam and its battery, when there’s sufficient sunlight. Once that drops below usable, the t-beam reverts to its own battery, all the while running in an extreme power saving mode like router mode.
Hmm. In is_router mode if the USB power drops too low it should run from battery for as long as it can.
If the battery gets depleted (on a tbeam, the other boards are different): you’ll need to press the button to boot it (it won’t come back up one usb power comes back).
Are you connecting a 5v regulated solar panel directly to the USB input? Measure the output as the light diminishes. Does it cut off below 5V or gradually decrease?
I’ll bet you the AXP192 stays on USB input down below 2.9V at which point the brown out detector on the ESP32 triggers. Hard to tell because I can’t find an English datasheet for the AXP192.
Nope, not a regulated 5V, so declines gradually. I know a regulated 5V would get around this as it works as expected when I use a powered USB hub to simulate it, but it seems the t-beam gets caught out if the supply declines (i.e. is not regulated).