I need some advice from an electrician and/or one of you wiring gurus out there. I have a 2011
Casita with the larger and more power-hungry rooftop A/C unit. Apparently, the pre-2010 Casita's would run the A/C with a 2000 watt
generator just fine (well, at least if you didn't have anything else turned on
). Since my A/C pulls about 200 watts more, I am concerned that I have even less margin and a cheaper 2000 watt
generator might not be enough. But my budget is going to be wiped out just trying to afford a 2000 watt unit, I really don't have the money to have to buy anything bigger. So I've been trying to figure out how to get by with a smaller
generator.
Plan A
Find an accessible spot in the power line leading to the A/C, cut the line and install a regular 20 amp male household plug on the side leading to the A/C, and a matching female plug on the end leading to the Casita’s 120 volt power. If you put a matching set of 20 amp plugs say, on the roof, you could temporarily unplug the A/C from the Casita's built-in power completely. If you then ran an extension cord up to the roof and plugged a generator straight in, the generator would be powering
just the A/C. The generator wouldn't even "know" the rest of the trailer existed. So it wouldn't be trying to recharge the
battery or power anything else. Meanwhile, you could also run as many
lights, fans and whatever as you had
battery power for. Note: this assumes you also have a
solar panel to keep the
battery charged.
Plan B
Install a manual switch that would temporarily disconnect the built-in battery charger(?). The objective would be the same as Plan A. Plug the generator into the regular shore power connection, make sure
nothing else is plugged into a 120 volt socket, and use the generator to power
just the A/C. I would
not want the generator to recharge the battery or supply power to any 12 volt systems until the charging system is turned back on (again, this assumes that I have
solar power to recharge the battery).
Question
Now, I am not an electrician. Even so, I'm about 99% certain that Plan A should work. Plan B I'm not so sure about. Do I need a need a disconnect switch on the battery charger? Do I need a switch on the (120 to 12 volt) converter? Again, the objective would be to temporarily isolate the Air Conditioner (and/or 120 volt system) from the 12 volt battery so that I could use a smaller generator to power
just the A/C without the generator being overloaded by trying to power
anything else. Conceptually, Plan A is simpler and more foolproof. Plan B might be easier mechanically, if the wiring is easier to reach. Is one method better than the other? For that matter, is my basic idea sound? It certainly
seems like isolating the A/C would help me to successfully use a smaller generator, but I'm new to all this.
btw – Still trying to save up for
solar panels next year. A generator is on my list. But I'm getting some
electrical work done next month, so now would be the time to get some of the wiring redone.