Originally Posted by le.breeze
OK now I am probably going to sound really stupid, but is there not a battery indicator built into the monitor display of the trailer?
Not stupid at all. I was under the same misconception when I started out. The one in the trailer can only provide a 'point in time' measure of the battery (by voltage I believe). It doesn't compensate for float, it doesn't know anything about the batteries capacity, it doesn't monitor your draw, etc...
You also have to be sure you're looking at the right scale. The battery lights scale as 'F', 'G', 'C' which stands for 'Fair', 'Good', and 'Charging'. You'll note there's no concept of 'Full' or 'Empty' on that scale. As soon as you start your generator, or plug into shore power, if you click the button you'll see all the lights light up. That's because it's 'Charging'. Some people (myself included in the beginning) would look at that and think the battery's full, because we're looking at it like a scale. In reality, it could be almost dead, but still be charging.