A common rule of thumb for sizing batteries to solar power relates nominal panel output in Watts to bank capacity in Ah.

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

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

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

For solar-only charging 2:1 or even 3:1 is recommmended. For shorepower- or alternator-augmented charging 1:1 or 1:2 may be sufficient.