Adding a Second Battery PLUS PLUS PLUS
On the issue of second battery, boy I was hooked by this issue.
First HECK YES. Two batteries is a minimum, unless you plan to spend most of your time on hook ups.
When I didn't know better, the dealer sold me a toy hauler with one battery and I learned that in a hour trip, it hardly charges and it takes hours to keep up if you use the generator to charge it.
Now flash forward, 14 year Even with all led lights, that frig has a small static draw to the low voltage system even on Propane and when I get cold at night I want to know that the heater fan will come on.
Having a generator is nice and we would not go without, but if you run a battery dead it takes a really long time to charge it with the Gen Set, so plan ahead and do not run them dead.
Battery Cut off YES, at least to cut off power to the coach. Every unit I have owned or helped out on has one, but it does not usually disconnect everything. Usually your emergency brake switch and your Tongue Jack go right to the battery, so if they have any leakage, there goes your battery. To that end, I would say, IF you install a cut off switch at the battery, be sure you either cut everything off or that you are satisfied with any possible leakage at the Tongue Jack or Emergency brake. Since it might not be a good idea to cut power to the emergency brakes, that might be a circuit to check and leave alone . It also looks like my generator is wired directly to the batteries and fused separate from the trailer so be aware of possible leakage there too if it sits long term.
We will not leave the trailer hooked up to shore power beyond the time it takes to chill the frig or empty it when we get home. We think it is a bad idea to leave the frig on all when not in use anyway. But the factory Charger/converter is, in my case and in many others I have seen, a crappy one size fits all with a low amperage flat voltage charge rate and none or poor long term maintainer circuits.
Here is what we did. Three Batteries and 200 watts of solar on the roof (easy job to install by the way) going through a good quality PWM charge controller with about three charge rate levels and a monthly cycle that knocks the sulfication off the plates. With the third battery I installed an isolation switch and disconnect it after we get in to camp. Because I installed a 2000 watt full sine wave inverter and now run everything we need including the Microwave, without a Generator until we want the A/C on, there is a chance of running the house dead. So I want the third battery as a back up. IF we get careless with the inverter, we are OK. I take that one out of the loop after we get in to camp and IF I manage to kill the other two, it is an easy flip of the switch to turn us back on and start the Gen Set. But, it has never happened and even watching Direct TV half the night with the heater coming on constantly, we have never burned the batteries below half charge according to the factory installed system monitor panel and never below 11.3 volts actual.
So in short Two or more batteries-the bigger and stronger, the better and add some SOLAR. The 200 watt system with upgraded controller, wires and connectors in hand were picked up for about $350 at the warehouse door of WindyNation.com in Ventura, CA.