DIY project, Electrical diagram, help needed!
I'm building my camper van on a Ford E250 extended platform with high top. Haven't bought any electrical stuff yet. When I'm done building this thing, I will be boondocking (nothing crazy) but a...
Forum Discussion
You have a lot of questions and uncertainty, and it's far better to ask them than to plow on without understanding what's happening. Getting help from someone more qualified would be a great idea, but you can also learn a lot by research and asking questions.
I think it's helpful if you think about the electrical system in three separate systems. There's a 120V system, a house 12V system, and a chassis 12V system. There are relatively few connections between them, although the vehicle chassis is a shared ground for both 12V systems. I'll only write about the 120V system here. Please bear in mind that, while I have some experience with wiring and electrical work, I'm not a licensed electrician or anything of that sort.
Here's a quick crude diagram of a possible 120V system. Neutral and ground connections are not shown, but should go to their respective bus bars in the distribution panel.
You don't need a transfer switch here, as your generator is not going to be permanently installed and hardwired. Just plug your shore cable into the generator when you're running on generator power. It may take a standard 15A to 30A RV adapter to physically connect. Basically, you're your own transfer switch. (Since it's a portable generator, you'll presumably have to unstow it and monkey with it anyhow, so plugging into it is no real extra difficulty.)
For a 30A shore power connection, you need 10 gauge wire (or heavier) going to the main breaker (as per the NEC). The various things that use power are wired to branch circuits from the AC distribution panel. They'll be on either 15A or 20A circuits; the former can use 14 gauge wire, but the latter require 12 gauge. It may be simplest to just use 20 gauge throughout and 20A circuits throughout.
The (future) air conditioner will require a dedicated 20A circuit.
The microwave/convection oven should have its own circuit, preferably 20A though 15A should, in theory, be sufficient.
Other things can be distributed as you see fit. I would probably put the converter or battery charger and fridge on one circuit (a "things that should not be powered by an inverter" circuit) and convenience outlets on another (a "things that can be powered by an inverter" circuit). I would not attempt to use the microwave/convection oven with an inverter with only two batteries; it would be a marginal setup at the best.
I'd suggest planning to put in an outside outlet somewhere. It's quite handy on an RV. It must, of course, be a weather-protected outlet.
For an inverter, there are a few options. By far the simplest is to just plug whatever you want to use with the inverter into a portable inverter and use it. For using a computer, or watching TV, you don't need a particularly large inverter; 600W should be plenty assuming you don't have a laser printer. (A laser printer uses a lot of power, and would be hard to run from an inverter with two batteries, much like the microwave.)
Somewhat more sophisticated and more costly and perhaps handier is to have some sort of a transfer switch that shifts some or all of the power for the RV to the inverter. This could be transferring only one or two branch circuits, which is why I suggested having the fridge and coverter/charger on their own circuit. It is also possible to switch the power at the input, so that the inverter powers any AC item in the RV. Doing this means you need to somehow switch out or switch off the things that should not or cannot run from the inverter, such as the battery charger/converter and the fridge in AC power mode.
I would suggest thinking about installing an EMS unit on the power input; Progressive Industries (not to be confused with Progressive Dynamics) makes some good but unfortunately not inexpensive ones. These devices check the incoming AC power for voltage, proper wiring polarity, and frequency, and disconnect the RV if it's not acceptable.
I think it's helpful if you think about the electrical system in three separate systems. There's a 120V system, a house 12V system, and a chassis 12V system. There are relatively few connections between them, although the vehicle chassis is a shared ground for both 12V systems. I'll only write about the 120V system here. Please bear in mind that, while I have some experience with wiring and electrical work, I'm not a licensed electrician or anything of that sort.
Here's a quick crude diagram of a possible 120V system. Neutral and ground connections are not shown, but should go to their respective bus bars in the distribution panel.
You don't need a transfer switch here, as your generator is not going to be permanently installed and hardwired. Just plug your shore cable into the generator when you're running on generator power. It may take a standard 15A to 30A RV adapter to physically connect. Basically, you're your own transfer switch. (Since it's a portable generator, you'll presumably have to unstow it and monkey with it anyhow, so plugging into it is no real extra difficulty.)
For a 30A shore power connection, you need 10 gauge wire (or heavier) going to the main breaker (as per the NEC). The various things that use power are wired to branch circuits from the AC distribution panel. They'll be on either 15A or 20A circuits; the former can use 14 gauge wire, but the latter require 12 gauge. It may be simplest to just use 20 gauge throughout and 20A circuits throughout.
The (future) air conditioner will require a dedicated 20A circuit.
The microwave/convection oven should have its own circuit, preferably 20A though 15A should, in theory, be sufficient.
Other things can be distributed as you see fit. I would probably put the converter or battery charger and fridge on one circuit (a "things that should not be powered by an inverter" circuit) and convenience outlets on another (a "things that can be powered by an inverter" circuit). I would not attempt to use the microwave/convection oven with an inverter with only two batteries; it would be a marginal setup at the best.
I'd suggest planning to put in an outside outlet somewhere. It's quite handy on an RV. It must, of course, be a weather-protected outlet.
For an inverter, there are a few options. By far the simplest is to just plug whatever you want to use with the inverter into a portable inverter and use it. For using a computer, or watching TV, you don't need a particularly large inverter; 600W should be plenty assuming you don't have a laser printer. (A laser printer uses a lot of power, and would be hard to run from an inverter with two batteries, much like the microwave.)
Somewhat more sophisticated and more costly and perhaps handier is to have some sort of a transfer switch that shifts some or all of the power for the RV to the inverter. This could be transferring only one or two branch circuits, which is why I suggested having the fridge and coverter/charger on their own circuit. It is also possible to switch the power at the input, so that the inverter powers any AC item in the RV. Doing this means you need to somehow switch out or switch off the things that should not or cannot run from the inverter, such as the battery charger/converter and the fridge in AC power mode.
I would suggest thinking about installing an EMS unit on the power input; Progressive Industries (not to be confused with Progressive Dynamics) makes some good but unfortunately not inexpensive ones. These devices check the incoming AC power for voltage, proper wiring polarity, and frequency, and disconnect the RV if it's not acceptable.
