Basically rectify mains AC via big-ass diodes and go straight into the battery.

It will not work for Lead Acid pack since it can't take so much current safely, it would boil and destroy itself. However, LiFePo4 battery can take 100-200 amp current without any trouble.

Although very simple, this approach requires much care in selection of wire, breaker, connectors, diodes, etc. Passing 100 amps at 120V is not as trivial as it sounds

P.S. Why am I not getting Email notifications from the forum? I have thread subscription configured for immediate notification, but its not working.
Anyone has same issues?