Hi,
Circuits are not intended to be run "flat out" so a 30 amp breaker can provide 24 amps on a continuous basis. There are (expensive) ways around this and some less expensive solutions.
I "broke out" the electric water heater and have male and female plugs so I can run the heater on a separate circuit.
The expensive solution is to use a hybrid inverter charger which will draw energy from the battery bank if the load exceeds a certain level (I keep mine at 24 amps). This is called "load support". Of course you can't do that forever--but the water heater cycles on for 15 minutes every four hours once it has reached full temperature.
Be aware that load support is NOT voltage support.
It may well be that with the fridge, water heater and roof air cycled on, that voltage became too low. That would cause the roof air to draw more amps. Then the breaker pops.
