A technical subject requires technically correct language. One amp for
one hour is one amp-hour. 167 amp days is a convertible unit, but not
a conventional one. To correctly express amp-hours implies watt-hours,
but amp days implies a basic misunderstanding or mis-expression of a
conventional arithmetic term, since techs use amp-hours. 167 amps at
nominal 12 volts for a day is 48,096 watt-hours, a big wack of power,
unrealistic given the circumstances. 6 amps all day is 24 hours times
6 amps is 144 amp-hours. At 12 volts, that's 1728 watt-hours, or about
as much as a fully employed electric kettle needs, all hour, every
hour.

So, you could charge the battery all day, if it's big enough, and then
boil kettles full of water to boiling and discard the boiled water,
not counting invertor losses, for about half an hour, maybe 6 kettles
full. Overall, you only get back about half of what you put into a
battery.

Terry K