More details on electrical upgrades, and we went camping!
On the electrical side, I want to ensure that certain circuits are shut off automatically when the inverter is powered up and running. This is important because I foresee more off grid camping in the future. I was also thinking about plugging in the shore power cable into the inverter to prevent the possibility of the inverter being turned on and connected to the main power while the panel is connected to shore power, but that would require making some holes in the trailer or to leave an access hatch open: neither options suit me. I also want to use 2 separate batteries: one dedicated to the 12 VDC circuits, and one for the 1 KW inverter I have.
Thus, some automation is required:
Step 1: have a background in electrical and also have a good friend that is an electrical engineer. hehe! :)
Step 2: do all the******listed below! ;)
I will need some 15 Amp relays that can handle a 120v current through the coil (the side of the relay that does the actual switching), as well as a time delay on make switch, and a 30 Amp contactor (high-amperage relay, in effect).
I will have relays connected to these circuits on the electrical panel: the soon-to-be isolated converter circuit, the air conditioner circuit, the water heater circuit, and the inverter's battery (battery #2). I will leave the microwave circuit on, and check the current requirements: if it's too high, then I will just not use the microwave on that circuit, but still energize it so the plug it's using is energized.
All other circuits are good enough - I'll just have to ensure that we don't have the fridge operating in Automatic mode.
How it will work:
Everything depends on whether the shore power plug is energized by an external power supply or not (i.e. is the cable plugged in and the circuit energized?). Thus, I will either turn on or off certain circuits depending on whe3ther there is shore power present.
When shore power is present, power will be allowed to go to a time on make delay switch. These are switches that allow power to pass through after a certain amount of time has expired. It is to give time for other relays to actually close or open before allowing power to go from the outside to to main electrical panel. It will prevent the panel from being energized by 2 power supplies (the shore power and the inverter).
Shore power will also turn off the power going through the control circuit for the inverter, as well as disconnect the output of the inverter from the main electrical panel.
Shore power will also enable the following circuits: Water heater, converter, air conditioner, as well as the battery charger for inverter battery.
This system will automatically change over from shore power to inverter duty, and back again safely, with no interaction required. The only thing is that I want to have some kind of audible and visual alarm when the changeover happens: maybe a light as well as a one-time beep when the changeover happens: this will notify me to change the fridge and water heater over to propane and back.
The steps are quite intricate, but at the same time, it's all very simple in design:
When shore power is present, the inverter side is shut down, and the high amperage devices get energized.
And when shore power isn't present, then the opposite happens. I am also adding an LED light as well as an audible alarm (that will beep only once) to alert me to when the shore power is disconnected.
Does anyone know what happens electrically with the fridge when shore power is disconnected? Will it kill my battery? If so, is there a way to prevent this from happening?
