What's the best overall electrical system

[cwf]

Here is the brief description of our upgrade from 30 to 50 Amp service on our 34' 1999 Excella last year..

Did it to support second AC and 'necessary' electrical demands.

http://www.airforums.com/forums/f37/...in-106918.html

I kept all the 12VDC stuff just like factory (but cleaned up connections)

Good luck!

[rodsterinfl]

@nomad pete, it sounds as if you want it very simplified for very little per se- TV, etc. Consider the costs. AGM or cart batteries are not cheap nor is solar. It has advantages- yes but it all comes down to your goal. I a have a 1000 watt inverter that I use for different things- coffeemaker, TV, DVD, etc. It is more than enough running on two regular batteries. I have a 2400 watt generator that is capable of running my AC and some other items simultaneously. I do not have a wide berth of extra power but the generator can also charge batteries or power the charger to do it and it is a simple 30amp system.

[TouringDan]

Jammer is correct. You can learn a lot reading on the forums, but nothing like going camping to learn stuff too. Of course, now you don't have a camper. You can still learn a lot with a tent. I went to a bluegrass festival 3 years ago and did not take my Stream cuz it was just too far. I was concerned about being too hot tent camping, so I bought a small inverter and my 50 watt, very efficient, 14" floor fan. It all worked fine.

I hear you on the 50 amp service, but I don't really think you need it. Especially if your camper is not large. 24 or 25 ft is a good length. I realize that you don't want to be too hot. However, instead of adding another AC unit, just take action to make your Stream more energy efficient. Insulate the vents and windows, so there is less heat gain. I have installed cellular blinds in my Tradewind. My windows are also heavily tinted. If I needed to, I could install insulation between the cellular blinds and the window glass. This will have many benefits- use less energy, AC unit will last longer, run AC on low so it will be quieter, etc.

It helps to understand amps and watts. Power consumption, watts, is just voltage x amps. So my tv power consumption is just 12v x 3.3 amps or 39.6 watts, and an AC unit drawing 12 amps is consuming 120v x 12 amps or 1,440 watts. It is pretty simple once you understand it. I really don't care about amps as I know the wiring will be plenty large enough; I just care about watts because this is what discharges your batteries. Sometimes the power consumption is listed on the nameplate like for my 14" floor fan. However sometimes the power is not listed, just the amps, so you have to calculate the watts, like for my tv.

They usually recommend discharging a battery down to only 50% of the full charge. Using the table in the picture below, this voltage is 12.06v. I am only going down to 12.7v after boondocking for 4 days, so I am in really good shape. I bring my 1,000 watt genny with my for AC if I need it, but I have yet to use it to recharge my batteries.

There is a lot to learn, but it is all fun stuff to learn.

Ask lots of questions, just like you are doing. We were all newbies once just like you.

Dan

[TG Twinkie]

The other thing to consider is. One air conditioner running in your coach will sound like a twin engine aircraft is in your living space. Two will sound like a 747.
These units are not quiet by any means. I doubt you would hear a Honda 2000 watt generator running inside your coach if you had the A/C on.
Not that I am recommending running the generator inside your coach.

[Nomad_Pete]

Ok first off I love tent camping, in the winter when I'm not working I practically live in one of my two tents. I broke down and bought a 4 season tent just for cold weather camping. When I'm camping I don't need anything except maybe a battery powered speaker for my iPod next to a campfire. Even when I get an airstream I will still tent camp because I love it.

My whole reason for wanting an airstream is to live in one instead of paying rent because I'm tired of paying 1200 to 1400 a month for an apartment I don't even like. So when you guys say the ac units are loud it begins to worry me. I generally enjoy having a fan for background noise but you make it sound like they will be super loud. I really like the look and feel of an airstream over other types of campers. Everyone I work with keeps insisting I get a toy hauler on a gooseneck. I really dig the airstream look though.

So I have a rather important question then regarding the use of an ac unit on a generator. I read a lot of people use a honda 2,000 generator for running ac. Now with an initial inrush amperage spike of 18amps at 120v that would yield a wattage of 2160 which would be more than the generator is rated for so wouldn't that potentially blow the breaker on the generator?

My new concern is now I want to hear how loud the ac unit is. I went to the local airstream dealer and I asked him during my tour of several new airstreams how loud the ac is and he said they are quiet.

Oh and we have a couple whisper lite honda generators at work and they are quiet enough for me to sleep next to. Now if the ac is way louder than that I'm probably going to have some adjusting to do.

Once again thank you to everyone contributing to this thread with every post I learn more. Several times someone has posted things I didn't even think to consider so I'm very grateful to have the info.

As of now I am totally leaning towards 50amp service with a generator of at least 2500 watt capacity. My new major concerns are what batteries to buy and how loud the ac unit will be. I would love solar panels or a wind turbine but the prices seem to high for me for what you get. I do really like the idea of solar though.

My other questions are what kind of adapters and power cords are necessary? I'm assuming you would want both 30 and 50 amp cords and adapters and a generator supply cord. What other stuff do you guys typically carry? Do you guys leave your batteries on trickle chargers or battery tenders when you store the airstream for long periods of time?

[Wayward]

Originally Posted by Nomad_Pete

with regard to a residential 200amp service no one ever really runs 200amps at one time so you can always add another breaker or run more than one high amp appliance at once. With a 30amp service and dual AC running from what I've read it's not going to work and if it does you can't really run anything else.

All AC distributions systems are the same. You can put as many breakers as will fit in the box. RV boxes are smaller, so less breaker slots. 220v boxes for RV "50 amp" service tend to have more slots because it brings in two hot wires at 120v each.

Originally Posted by Nomad_Pete

It also seems that there is some variation between rv hookup sites and that good power sources are hard to come by.

Most have three plugs. 50a/220v, 30a/110v + 20a/110v with good power. Your main design decisions on power distribution are not affected by the occasional campgrounds with low voltage, open neutrals or mis-wiring. Just add the appropriate protection devices once you get it figured out.

Originally Posted by Nomad_Pete

I still slightly confused when people say the 50amp breaker is essentially 240v but for the rv it's two 110 breakers. So I guess my question is does the rv distribution panel take the 50amp 240v and split it into two 120v breakers?

240v is really not very different once you figure out the wiring. Maybe the picture below will help. It shows what is inside the the power pole transformer feeding the campground box (or your house panel).

There are two HOT wires that measure 240v across them. Hook your 240v oven across them and it works. The ground+neutral is for safety.

But there is also a center tap on the transformer called the Neutral. Each of the two HOT wires to Neutral will measure half the voltage (120v). Neutral is tied to ground for safety.


One slot of the "30 amp" campground outlet is hooked to one of the HOT wires. The other slot to the Neutral tap wire, providing 120v service to your RV distribution panel. The third slot goes to Ground. This is what most Airstreams hook up to.

One slot of the "50 amp" campground outlet is hooked to the HOT1 wire, the the other slot to HOT2 providing 240v service to your Airstream. The third slot goes to Neutral and the fourth to Ground. Consider neutral and ground redundant for now, for simplicity's sake.

Originally Posted by Nomad_Pete

If that is what it does then does then do you have a 50amp circuit breaker or do you have two 20amp breakers?

The main breaker for the 30a/120v distribution panel monitors the current flowing from HOT1, to Neutral (a single pole breaker).

The main breaker for the 50a/240v distribution panel monitors the current flowing from HOT1, to HOT2 (a double pole breaker).

If you have 50a/240v service, the breaker panel brings HOT1 down one side of the panel and HOT2 down the other side of the panel.

Notice how the tabs that the breakers slip onto are "interlaced". Every other one is a HOT1, sitting next to a HOT2. A double pole breaker connects to two of these tabs providing a complete 240v circuit by connecting the black wire to one breaker terminal and the white wire to the other.

A single pole breaker connects to only one tab. It provides a complete 120v ciruit only after you connect the white to the neutral tap wire.

Originally Posted by Nomad_Pete

I just want a generator to run at least on AC unit and some supplemental power if I do buy one. Where I would be boondocking hopefully I wouldn't need AC to often.

So why not buy the Airstream with one A/C unit and 30a/120v service? Use it for a while with 30amp campground service or a single generator.

If you then decide you need two A/C units, upgrade to 50a/240v service. You could put the "essential loads" (one 120v A/C unit) on one side of that panel with all the existing Airstrream 120v AC lines. The second A/C unit and the new appliances go on the other side. Feed the new Airstream panel with a 4 prong 50a/240v cable at the campground. When boondocking you can wire a 120v-to-240v plug adapter (4prong to 3prong) so that the generator feeds 120v to the "essential" side of the RV panel.

Originally Posted by Nomad_Pete

I feel I may be coming off as someone who needs way to much power.

No such thing as too much power . If you decide to rewire the Airstream go for 50a/240v. Minimal extra cost and space but lots more flexibility.

Originally Posted by Nomad_Pete

I So thank you to everyone who is posting. I truly appreciate the knowledge.

You are most welcome!

[Wayward]

Pete, if your main concern is a second A/C unit there is another option for you wihtout upgradig to 50a/240v. Like I wrote above, 50a/240v campground pedestals have 2 50a/120v circuits inside. They look like this:



The 30a/120v and 20a/120v receptacles (and their breakers) are on one 120v leg.

The 50a/240v receptacle and breaker is tied to both 120v legs.

You could run a 12g wire from your second AC to a compartment and plug it indirectly to the 20amp receptacle when at a campground or to your second generator outlet.

[TG Twinkie]

There is a problem with Wayward's description of the 240 volt system. If I am reading it right.
He talks about a white wire connecting to L2 or Hot 2.
This is not correct.
In a 3 wire system:
Black = L1
White = N
Green= Grnd

In a 4 wire system:
Black = L1
RED = L 2
White = N
Green= Grnd

The white wire should not be used for a hot leg in any system.

[Wayward]

Originally Posted by TG Twinkie

There is a problem with Wayward's description of the 240 volt system. If I am reading it right.

He talks about a white wire connecting to L2 or Hot 2.
This is not correct.
In a 3 wire system:
Black = L1
White = N
Green= Grnd

The white wire should not be used for a hot leg in any system.

Good catch! - I should have said red wire

I was describing how to wire into a double pole breaker in the breaker box. The two hot wires (black and red connect to breaker). White to neutral. Bare to ground.


You will occasionally see a black and white wire hooked directly to a breaker in a breaker box when it is a 120v GFI breaker. But as you say it is not acting as a hot.

[JimGolden]

Great technical posts Wayward! Really good info!

As to weight, the new PD4500 series are quite a bit lighter than the old unit you replace. You will probably come out close to even with the over all modern 50amp system vs. the ancient 30amp one, weight wise.

You will need to run a heavy wire from the PD4500 to where you connect your shore power. Guys can argue this, and there is some "slop" in how you interpret the electrical code. A friend of mine, who is a very good electrician, said I could use an 8 gauge wire for this. Reading the code one way, you could. But if you looked at a little differently, the 8-wire was marginal. So, I used a 6-wire (you get into amp capacity at temperatures, etc.).

My biggest issue was the old one was short and wide, the new one was tall and narrow. I didn't want to mount the new panel sideways, so I had to modify the cabinet. I had to "fill in" on the sides and open up top and bottom a bit (fortunately I had room to do this and keep the panel in the same location), then I had to make a spacer to set the new panel 3/4 inch in toward the center of the coach because the PD4500 was a little deeper than the univolt. But, it made a nice install. I routed the 6 wire through the cabinets, under the floor, across the belly pan between frame rails, and popped back into the compartment where the shore power plug was supposed to go. Make sure to use appropriate supports and "pads" to keep the wire from ever getting chafed.

Originally, I had 40' of 30amp chord that the PO had hardwired to the coach, so I had to coil that up every time and stuff it into the compartment. But with the 50amp, I have two stand alone chords. One is a 30 footer, the other is a 15 footer. Depending upon how the campground is configured, I'll use one, the other, or both. I have a 30 to 50amp adapter pigtail for the places that only have 30amp (like my garage plug that I wired up many moons ago) and 20amp to 30amp plug to use the genny.

Thus far it's worked well for me.

The 50amp chords aren't that bad to wind up. I have two big Rubbermaid boxes I store them in. Keep one under each side of the dinette. If they lay in the sun, they flex pretty well. If it's cold out, they can be a bit stiff. But nothing to worry about. They make high flex 50amp chords, but they cost double what the normal ones do, and the normal ones aren't cheap.

I only have one a/c unit, but it's a 15,000btu and it does a very good job. Here's another trick for you: Paint the roof high gloss white. I did that first, and that alone cut the temp gain by 10 deg. F alone. That allowed my tired old 13,500 a/c to cool her down. But when it finally died (and I'd run it on a hot wired control board for a year....two toggle switches, for fan on/off and compressor on/off and no thermostat control....it was safe, but you'd wake up in the middle of the night and see your breath....) I decided to get a 15,000btu. If you do both of these mods, I'd bet one a/c would do you just fine.

Hope this helps!

See ya,