AC vs/or DC?

[Spoolin]

Trying to figure out what/how involved I want to get in setting up the house electrical system. Ideally I'd like to have an inverter and run everything on A/C power. That way I don't have to deal with converters and DC appliances. Is this realistic? Is it one or the other or does it have to be both? Are there some things that I will have to have DC to run and there's no way around it?

If it's one or the other what are the merits of a full DC set-up vs a full A/C set-up?

Thanks

[carringb]

A/C will mean smaller wires. Staying with 12v means you will have some giant wires running to large loads. Also generally cheaper appliances.

A good inverter also generally has more 12v charging output than most 120-to-12v converters.

[86Scotty]

DC is there already. Most RVs have both to take advantage of cost and convenience. You want AC receptacles for the home stuff you take along, so you'll probably want an inverter, but some things are best DC, like a furnace (propane probably but DC blower motor), and water pump will be DC if you have one. I think both is inevitable.

[McZippie]

If there is a choice between 12 volt and 120 volt components, I use 12 volts. Just running the inverter with no load uses 3 amps.

In our Rig components such as, LED TV, Roku, Wireless Air Card Router, DVD Player all came with 120 volt plug in 'brick' converters. The bricks convert from 120 volts AC to DC. Radio Shack sells the correct plug in and DC voltage adapters to run all on 12 volts.

The 120 volt system (shore power, gasoline generator or inverter) only needs to be used rarely to power the battery charger/UPS, microwave, electric water heater and Air Conditioner.

Espar diesel furnace and engle fridge run on 12 volts.

We don't have propane systems and would of liked a small a diesel generator, to have a one fuel Rig.
The only small diesel generators I could find were Marine models that are very expensive and would of required a lot modification to fit under the floor.

[86Scotty]

Originally Posted by McZippie

In our Rig components such as, LED TV, Roku, Wireless Air Card Router, DVD Player all came with 120 volt plug in 'brick' converters. The bricks convert from 120 volts AC to DC. Radio Shack sells the correct plug in and DC voltage adapters to run all on 12 volts.

Hmmm, I never thought about that. Great idea!

[daveb]

Originally Posted by Spoolin

Trying to figure out what/how involved I want to get in setting up the house electrical system. Ideally I'd like to have an inverter and run everything on A/C power. That way I don't have to deal with converters and DC appliances. Is this realistic? Is it one or the other or does it have to be both? Are there some things that I will have to have DC to run and there's no way around it?

If it's one or the other what are the merits of a full DC set-up vs a full A/C set-up?

Thanks

In my opinion you’re better off with both systems. Yeah it will cost you more in wiring but with 12V LED lighting it allows you to use minimal power when boon docking on battery power only.
Inverters use power just to operate and you need to keep the DC draw as low as possible. But some of the bigger stuff like a microwave requires AC. A generator is fine, but might bother other campers or park rules might not allow usage after a specific time.
So the way I see it is
I’d have a DC system using a good battery system with a large enough inverter to run only those items needed when off shore power and that has the ability to smart charge the battery system. Add enough 12vDC power plugs to charge or use small things like cameras, computers and what not. A good DC run for the LED lighting, fans, and pumps. Many heating systems also use DC. A good separator may not be needed because when you hitch up the trailer, the charge from the vehicle will be from the trailer plug. That is something you might have to upgrade on the vehicle. Your generator doesn’t have to be tied into the DC system provided it is tied into the AC shore power system which generally has an automatic transfer switch. Here is where an inverter is used to charge the battery system…plug into shore power or fire up the generator and turn on the inverter to run AC stuff and charge the battery if needed. The inverter needs to be large enough to run the largest component plus other items at the same time if required but more than likely you will use the generator if you have one. It is possible to run a microwave off the inverter and batteries only, but the battery bank will have to be fairly large (I have two 220AH batteries). I use mine on a regular basis for times up to 10 minutes on low power. Sure is nice to be able to be stealthy and not wake everybody. You can also have a smaller backup inverter somewhere on the vehicle so you don’t have to run the big inverter. I carry a couple smaller ones but even those do hog a bit of DC power. If I can run something off DC, I’ll do it rather than invert power to run it. The wire going from the main inverter to the house battery system will be heavy gauge (depending on wattage of the inverter), so the closer the inverter is to the house battery system the better. The inverter should run off the shore power input then output to a standard RV electrical panel. If there are any AC/DC items that specifically switch to AC when the item(s) sees AC power, you should have that AC circuit on its own breaker so you can shut the breaker off when the inverter is on and you are off shore or generator power. In other words you don’t want an AC/DC appliance to run off AC inverted DC when DC battery power is present…it just wastes power inverting it. All the other house AC outlets can run off other breakers but those around water need to be GFI rated. Also don’t forget about solar and pre wire for that as well. You’ll need wiring from the roof to the controller (or where it will be) and from the controller to the batteries. And make easy access to the batteries, fuses (and separators if used) for maintenance and removal.

I’m sure the trailer manufacture will know how to do this all of this. There are several electrical designs from complex to simple when setting up your system. One note on converters/chargers. In the past most of them were junk when refering to their charging system. Aviod those brands/models. If you have a need to run a heavy DC only load item while on shore power, converters are a good addition. You'll have to research them to see how far advanced they have come in offering a good charging system. Remember converters do not make AC and require shore power or a generator to make DC.

Good luck
Dave.

[carringb]

While you are doing the wiring, I would strongly suggest adding some hard-wired USB outlets.

That is one item I constantly wish I had in my van. I just use a cigarette lighter with 4 USB ports, but that means more wires cluttering the dash, and with 4 devices plugged in charge times get long since the 4 plugs only can handle 2.5 AMPs max.

[daveb]

Originally Posted by carringb

While you are doing the wiring, I would strongly suggest adding some hard-wired USB outlets.

X2, I have several of those Go-Pro cameras and it is nice not to have stuff all over the place. I also wish I had stereo wire plugs so I could have a set of outside speakers. If you're planning a TV, surround sound is nice as well. Pre-wire for that and any sat antenna stuff and what not.

[BroncoHauler]

When I had some work done on my teardrop late last year, I had them install one of these. Now I'm thinking that two may have been an even better idea. Dual USB socket.



http://www.bluesea.com/products/1016


Herb

[dhally]

We went the other way, towards all 12v. An inverter is inefficient and just more space and weight. Same with a microwave. We did install 120v shore power for those times when we are in an RV park to save the draw on the batteries. We installed a 120v receptacle inside, and its main use is for power tools when working on the van...

We put 12v receptacles on both sides in the living area to charge cell phones etc.