Honda eu1000i voltage question

I'm not sure how many amps are going into the battery. How do I figure that out? The trailer has a Progressive Dynamics 9245 converter. I'm going to assume that means 45amps when running flat out. My batteries were not dead, so I would assume that there were far fewer amps being pushed. The generator was basically running at idle speed.

Thanks for the responses so far. I feel better knowing things are as they should be.