The power going to your house is AC. Batteries are DC. In order to charge a battery you have to convert AC to DC. You do that with a rectifier normally or an AC motor/DC generator set. The problem with fast charging is the current (Amps) required.
The quantity of energy is KWH (Killo Watt Hours). If the battery stores 30KWH then it would take 30KW (the rate) for 1 hour to charge the battery.
For a discharged 48 Volt battery the charging current for one hour would be;
I = 30 KW (charging rate) / 48 (charging voltage) = 625 Amps.
If you cut the time to 6 minutes then the current would be 10 times that (6,250 Amps). I wouldn't want to be anywhere near that operation.
The ampacity of wire depends on it's cross sectional area.
A current of 625 Amps is close to the spec for 2000 MCM (depending on temperature rating), which is 1.92 inches (48.8 mm) in diameter, so it would require buss bars. The fast charge rate (6 minutes) would require over 10 times that conductor cross section area.
Conductors that big are not manageable by hand and currents that high are very dangerous.