(Apologies for my electrical newbieness)
For my application, after loss of USB power I need the Dash to stay alive long enough to send a single “power lost” message. Easy, just plug in a small Li-ion battery. Except it might be many months, even a year, before external power is restored. So I’m looking at a supercapacitor instead, since it’s fine even after sitting fully discharged.
Questions:
- Is this the wrong approach?
- What’s the right place to connect it? The normal battery connector (thus running through the charge controller)? Direct to Vin?
- Any specific part recommendations? I’m happy to overbuild it a bit.
- How do I account for the internal resistance of the capacitor, system minimum voltage requirements, and transmitter power draw?