Here is a typical 30AMP trailer wiring configuration showing you what works on what.
You need to have a BATTERY INSTALLED before you move your trailer down a public road. There is a DOT REQUIREMENT that your trailer has a BREAKAWAY system setup to stop your trailer if it breaks loose from your truck. The electric brakes will use your on-board battery to stop the run-away trailer. Without a working BREAKAWAY system installed might go against your insurance claim big time if it was determined you were traveling without a battery and your run-away trailer caused damage to something or worse loss of life etc... I would get a battery installed... Most dealers install the GP24 SRM24 12VDC 85AH Deep Cycle Marine & RV Interstate battery. They cost around $90 I think... Best place to get one would be the RV dealers. They will have many in stock to put in their trailers for sale.
ignore the POWER INVERTER description in the bottom left of the pictorial. It should read 12VDC to 120VAC ...
Roy Ken