70-80 degree tilt will produce a lot more at latitude 45+ from Nov. 1st to end of February, but at the expense of much less production kWh per month during the rest of the year.
In an off grid totally battery reliant pv system such as for some telecom applications you design the PV for December, worst month of the year for kWh production. If it will "survive" December and provide enough for the load to run 24x7 then it'll be fine for the rest of the year. At high latitudes this cha mean a 75-80 degree tilt facing south.