Here's a concise and handy guideline that was included in the
installation manual for my new Victron charger:

Problem: Charger does not function
Possible Cause: Inadequate AC power. (Restore or reconfigure AC)
Possible Cause: Input or output fuses defective. (Consult your dealer)

Problem: The battery does not get fully charged
Possible Cause: A bad battery connection. (Check connections)
Posible Cause: Battery type selection switch set improperly. (Change
switch settings)
Possible Cause: Battery capacity is too large. (Make sure charger
capacity matches battery)

Problem: The battery is being overcharged
Possible Cause: Battery type selection switch set improperly. (Change
switch settings)
Possible Cause: A single cell in the battery is defective. (Replace
battery)
Possible Cause: Battery is undersized for charger. (Consult battery
supplier)