[Wavery]

I second Dave's comments. Charging the battery from an idling TV engine is not only inefficient, it is dangerous.

I have a Honda 2000 "Quiet" generator. It's an expensive "Battery charger" but it has other (obvious) benefits.

However, I installed 160W solar panel array and I don't even bother bringing the generator camping anymore. It not only resolved the towing issue, it resolved all of the issues with battery charging and electrical consumption while camping.

The cost of the (DIY) installation was around $650 (Honda generator was $1,000). We use all the electric that we want (no LED lights) and never even think about electric anymore. The panels are even sufficient for mostly cloudy days when combined with 2, 6V batteries (additional $300). The other benefit is that you don't put any fuel in them and they add re-sale value to the camper. We could camp for 6 months and never be concerned about the batteries.