Combining 110v & 12v charging systems
A solar Panel puts out an unregulated charge, so long as there is sunlight, regardless of battery voltage (state of charge). A Solar Charge Controller could provide "Regulated" output.
Your Xantrax 110V Battery Charger senses the battery voltage, and varies itís output accordingly (so long as 110V is applied).
Hence, you donít want your Solar Panels connected at the same time as your AC Charger - the Voltage output from the Solar Panel would ďfoolĒ the AC Charger, and reduce itís output.
Put a disconnect switch in series with the positive output of the Solar Panel (& Blocking Diode, if equipped).