I am looking to build a UPS circuit using supercapacitors.
I have seen a number of circuits posted online, and a lot of them look very complex (some using lipos, some using NiMH etc).
Please note, I do not know electronics and the extent of my knowledge is pretty much being able to follow a circuit and soldering it (as long as it's not too complex).
I found the following circuit and was wondering if it would work for the Raspberry Pi and other 5v based SBCs.
Could I potentially use 300f supercaps with this circuit?
The web site says that it supports 5v at 2.5A. How do I calculate how long I could sustain 5v at 1.0 - 2.5A with this circuit (or using larger caps e.g. 300f supercaps)?
Can I modify the circuit to trigger the GPIO pin on the SBC when it switches to backup mode (i.e. DC power in fails)? The GPIO Pins on most SBCs are 3.3v.
My goal is to build a circuit that could keep a board running for a couple of minutes at the most (assuming a current draw of around 1 - 2A on backup power). Around 2-3 minutes would be great, or around 1 minute minimum.
I also need the circuit to be able to provide around 2.5A when powered from the wall wart (and whilst the battery is charging).
The other problem I am having is when I download the LTspice version of the circuit, it shows the supercaps as 5m. When I change it to 50f, the simulation does not seem to work correctly.