I am relitively new with RV life.
I have a 2012 Forest River Class C.
When we bought the coach the 12v tv would not turn on. I suspected the coach battery was weak so I replaced it last year. The tv would turn on, run about 30 minutes or so and then turn off.
This season I have started looking into it again,
I had the starter on the generator replaced, and was testing it before our first trip this season. I disconnected from shore, and started the gen and put it under load. After about 45 minutes, the lights dimmed and flickered. I began to trouble shoot. The battery had dropped to 95% during this time. I shut the gen off and charged the battery back to 100%.

After working all week, I grabbed my multi-meter and ran some tests
The battery volts read
13.3 at rest
13.63 on shore
13.08 on chassis at idle
13.56 on the generator

Over about 15 minutes or so, checked the battery and it was down to 95% again. (What the trickle charger will display)

The battery will not power the leveling jacks if the battery is not 100%.

Any ideas on where to start?
Like I said, this is our first RV, first time really using a generator, and I usually run away from electrical....

So the perfect storm.

So what you just described sounds like the generator isn't actually do any charging. Older one? How long did it sit in the past without use?

It only has about 100 hours on it. It is an Onan, and I have no reason to believe that it has been replaced. We bought the home two years ago and really have not used the gen that much.  

The tv turns off while on shore. I have not tried it on the gen.

your battery should read 14.4 during charge. it sounds like you have trickle chargers.
I dumped my lead acid and went lifepo, i'll never go back. I got a 20 amp 14.4 charger for shore recharging but if I was to use a generator I would get a 40 amp unit.
400w solar does must of the work except for extended bad weather.