[Alan Anderson]

Thank you for contributing this. I have a few questions, however.

First, you say "The one from ifirobotics does not work." We used it last year, and we're using it this year (with the addition of a series diode on the input). It's working fine for us. What's not working for you?

Second, you've labeled it "FIRST Backup Charger". Is it from FIRST, or is it your own design? Putting FIRST's name on it implies that it's somehow official.

Third, I'm concerned about your apparent use of a 3A fuse in the main breaker panel. That violates the rules. You have to use one of the 20A KOP breakers for custom circuits. You are permitted to use additional fuses as part of your custom circuit, but you still need the 20A snap-action breaker.

Finally, can you describe the operation of this circuit? For starters, the transistor on the regulator's voltage adjust pin is not self-explanatory.