120v plug trips the source breaker

If you mean that the House circuit breaker keeps tripping...check the breaker amperage.  Some house circuits are only 15 amps. If you have your electric heater element on the Pod turned on, the amperage may be setting off the breaker.
Turn off all of the Pod's breakers then plug into the household circuit.  If the breaker pops, you have a wiring problem either in the Pod input circuit...the extension wire, or in the house breaker.  If the breaker doesn't pop at that point, activate each Pop breaker/fuse one at a time.  If any of these pops the breaker you have found the problem.

Welcome.  You should be able to run the pod from a 15 amp outlet, as long as you don't use most of the high-amperage items.  As mentioned, the electric element in the water heater is one, the microwave is the other.  If your battery hasn't been charged in the last month it will be a big load for a while until it charges some.  Basically only have the lights on.  The A/C only uses 1000 watts so believe it or not you can use it - but make sure the battery is mostly charged.

If you are still tripping the circuit breaker then there may be something else on that circuit in your house that is also running, or the circuit breaker may be bad and need to be replaced.