A common rule of thumb for sizing batteries to solar power relates nominal panel output in Watts to bank capacity in Ah. It is not gospel. It is not a commandment. It is a quick heuristic to understand how your system is biased.

1:1 == 200W solar + 200Ah battery bank.

This generally considered the minimum, though it will likely work out fine in sunny areas with light loads. It may not be enough in the winter when the sun is low and daylight short.

Power rationing may be necessary.

2:1 == 200W solar + 100Ah of battery.

This slightly overpaneled configuration brings in extra power for heavier loads or for use in areas without much sun.

3:1 == 300W solar + 100Ah of battery.

This significantly overpaneled configuration generally yields an excess of power, making usable power in rain, winter, overcast conditions, etc.

1:2 == 100W solar + 200Ah of battery. (underpaneling or overbanking)