Has anyone tried something like this? If you don’t know, 120VAC(RMS) is 170V peak voltage. The input can easily handle the battery voltages we see, 75-90V at the input. Most power supplies will convert the AC is rectified DC, filter it a bit and then switch it at a higher frequency before stepping down from there.
The only thing I see happening which would give me something to look at would be the fact that all the input is basically using only two of the 4 diode in the bridge rectifier but then again, the other two are always just blocking anyways so not too big a deal. The other thing is that the lower input battery voltage would therefore pull higher current for the same output current. But if you want 3A then get a 5A setup and you’re covered.
Might be handy for any extra loads people might add like holiday lighting, music, etc and way less money than a special purpose converter.