Sounds like it is a little overloaded.
I would suggest checking the connections in the 120 volt AC panel.
Disconnect from shore power, remove cover from the 120 volt AC breakers, tighten the connections on the circuit breakers, look closely in back of panel for the neutral buss bar(where white wires connect) Tighten the wires on neutral buss.
I would suggest before starting to go to hardware store and get some electrical de-oxidation grease. Many of the neutral buss bars are aluminum or other material then good copper. The electrical grease will help to prevent oxidation which increases resistance which increases amperage.