Sorry, hadn’t understood that you’d charge the caps out of band. That makes perfect sense, if there’s a diode in your buck converter I don’t see why that wouldn’t work. I’m guessing I was projecting my use case onto yours with the charge system re-use part.
Check out this thread where the user build a little rig to do hard resets when required: Help with Python coding to make the goTenna stay on. OP has a functional prototype now.
Other little observation, while checking amperage draw the additional cabling set up in the battery circuit caused the faint flashing red, despite the fact that there was no significant voltage loss at the battery terminals on the GTM. Maybe the charge circuit is sensitive to battery impedance or something?
Todo list on my end:
- Try a single supercap (5.5v rated coin-type 1F) directly on the board
- Figure out the charge curve
- Find the internal battery cut-off voltage