The RV of the future
Over the years, particularly after Burning Man, I've written posts about how RVs can be improved. This year I did not use an regular RV but rather a pop-up camping trailer. However, I thought it was a good time to summarize a variety of the features I think should be in every RV of the future.
We keep talking about smart power and smart grids but power is expensive and complex when camping, and RVs are a great place for new technologies to develop.
To begin with, an RV power system should integrate the deep cycle house batteries, a special generator/inverter system, smart appliances and even the main truck engine where possible.
Today the best small generators are inverter based. Rather than generating AC directly from an 1800rpm motor and alternator, they have a variable speed engine and produce the AC via an inverter. These are smaller, more efficient, lighter and quieter than older generators, and produce cleaner power. Today they are more expensive, but not more expensive than most RV generators. RV generators are usually sized at 3,600 to 4,000 watts in ordinary RVs -- that size dictated by the spike of starting up the air conditioner compressor when something else, like the microwave is running.
An inverter based generator combined with the RV's battery bank doesn't have to be that large. It can draw power for the surge of starting a motor from the battery. The ability to sustain 2,000 watts is probably enough, with a few other tricks. Indeed, it can provide a lot of power even with the generator off, though the generator should auto-start if the AC is to be used, or the microwave will be used for a long time.
By adding a data network, one can be much more efficient with power. For example, the microwave could just turn off briefly when the thermostat wants to start the AC's compressor, or even the fans. The microwave could also know if it's been told to cook for 30 seconds (no need to run generator) or 10 minutes (might want to start it.) It could also start the generator in advance of cooling need.
If the master computer has access to weather data, it could even decide what future power needs for heating fans and air conditioning will be, and run the generator appropriately. With a GPS database, it could even know the quiet times of the campsite it's in and respect them.
A modern RV should have all-LED lighting. Power use is so low on those that the lights become a blip in power planning. Only the microwave, AC and furnace fan would make a difference. Likewise today's TVs, laptops and media players which all draw very few watts.
A smart power system could even help plugging into shore power, particularly a standard 15a circuit. Such circuits are not enough to start many ACs, or to run the AC with anything else. With surge backup from the battery, an RV could plug into an ordinary plug and act almost like it had a high power connection.
To go further, for group camping, RVs should have the ability to form an ad-hoc power grid. This same ability is already desired in the off-grid world, so it need not be developed just for RVs. RVs able to take all sorts of input power could also eventually get smart power from RV campsites. After negotiation, a campsite might offer 500v DC at 12 amps instead of 115v AC, allowing the largest dual-AC RVs to plug into small wires.
With today's electronics, the truck engine might be usable as a main or boosting source of power. While most vehicles come with smaller alternators (80 to 100 amps) there are readily available high power alternators that can deliver 2.5kw or more. (The truck engine is capable of 100s of kw of course.) New systems developed for hybrid cars are making this technology better and cheaper. This might allow a vehicle to have an even smaller generator, and start up the truck engine at rare times for a special boost or recharge. They are getting to the point where engine start/stop is getting so efficient that hybrids stop their engines at red lights. Designed from the ground up, an RV might do fine with just the truck engine and no generator at all. It's expensive to run a truck engine at idle, and not that efficient to run it at low revs, but you need not do that with the battery, alternator and smart power controller at hand. It may even make sense to add a solar panel (though solar panels tend to be pretty wasteful on RVs since they only are used when parked and one is often parked in the shade.)
Smart power can also mean shutting down appliances when another load comes on. So if you are running the AC and somebody wants to run a hair dryer, toaster or other short term stupid load, you can shut off the AC for a few minutes. (This is similar to the idea of the microwave shutting down briefly during AC surges.) In general a smart power system would track loads and shut down lower priority loads or loads that can handle it when other power demands appear.
Now if you want to get into the appliances found in bigger RVs like washer/dryers and dishwashers, you may just have to accept they only work on a high-power connection. Though even those can be made smart. An electric clothes dryer uses a ton of power, but it can happily shut off the heater briefly. (Propane dryers might make more sense in any event.) Dishwashers and washing machines can shut off heat or even motors for short periods with little harm. If a person fires up a toaster, they might notice the dishwasher stopped but it's not a big problem. Many of these devices need not be that smart -- they can handle just losing power for a while in many cases, though the newer ones which are smart but not that smart can bet upset at this. Even though a clothes dryer might take almost all of the 30 amp circuit, if it can turn off its heater when there are other demands, it might well be able to coexist with a lot.
Cooling and Heating.
The AC is the prime method of cooling, but in the southwest, swamp coolers are much more efficient and quieter, as long as water is not in very short supply. RVs meant for that region should consider having these. All you would need would be a vertical panel, perhaps in the wall, which can have water drip over it as the air blows from the fan. These can run on 40 to 80 watts, barely needing a generator. Swamp coolers don't cool sealed vehicles very well, they are better bringing in dry outside air and cooling it to blow on you, so it does take some design of the ducting. They are no good where it's humid.
When you have an 80 gallon water tank handy, you can also do things to make cooling and heating more efficient, if people don't mind wide variations in temperature of their water.
RV fridges are no-moving-parts systems which heat ammonia water up to emit the ammonia, which then condenses and cools. So they spit out a fair bit of heat, through a vent to the outside. There should be an option to have a small fan and electronic vent so that heat can be brought into the vehicle at night when it's cold. Why waste heat?
Water tanks and pump
The plumbing in an RV is even more important than the power to many. If you go dry camping, you want large tanks for fresh water, gray water (drains) or black water (sewage.) Normally as your fresh water empties, your gray water fills up. Why not put both tanks in the same space, as rubber bladders. You could not have both full but rarely does anybody ever want to.
The gray water, by the way, can also be used as the source for water to flush the toilet. I've also seen people build (outside an RV) a recirculating shower that let you shower forever on a few gallons, but I don't know if the safety folks would ever approve that. Possibly if you had a filter and loaded the water with extra chlorine or bromine. Sure, showering in high-chlorine water isn't great but not worrying about show length can make up for that. Clean your rear out at the end and do final fresh water rinse after throwing a switch to turn off recirculation.
While there are drinking water safe rubber bladders, we should also realize that almost nobody drinks the tap water in an RV, because you never can be sure how well sanitized the water tanks are. So accept that, and put in a small drinking water system for bottled water at the sink. If it uses a bladder it can take advantage of the pressure in the main system, too. You can brush your teeth fine in the bathroom sink with the internal fresh, non-drinking water. Or you can just do like most RV people do now, and drink bottled water.
The water pumps on most RVs are too noisy. It's annoying getting up at night, and running a little water for the toilet or washing only to hear "brap-brap-brap" waking up your companions or campsite neighbours. Here an air bladder could be the answer, at least for the night. (Turns out this is available, I just haven't seen it.) For a shower, you might need the bigger water pump or a noisy air pump, but I bet we could do better on that. I should note that one value of the sound is it lets you know if you have a leak or have not turned a tap fully closed. It makes it very overt that you are running water, and that's good to be reminded of when dry camping. An alternative might be a quiet system and a smart alarm that makes a noise when you run water for too long, or if the patterns of a slow drip become apparent.
A two-bladder system for fresh/gray would make it harder to measure the levels of the tanks. That's OK because the meters they have today are usually close to useless. However, better methods are available today, such as pressure transducers (if the fresh bag is on top) or reflected light. You should not normally have to measure the gray, because it's impossible for the gray to fill up other than by draining the fresh, unless you have another source of fresh water -- which you know you can't do unless you are doing outside showers.
New ideas for the toilet are harder to come by. Some already existing -- composting and incinerating toilets, for example. I continue to push for design of more accurate sensors for the black water/sewage tank, perhaps based on pressure or something else better than the current system, which fails quickly as toilet paper gets stuck to sensors.
These days, toy haulers are becoming very popular as RVs. These are RVs built on an open plan. Beds raise up to the ceiling, couches and tables fold into the walls, and the back becomes a garage for ATVs, dirt bikes, etc. I admit I am tempted by one of these if I could find one able to hold my 17' 6" art car.. I like the open plan, though the downside is your vehicle is full when you make short stops. (One nice thing about RVs is if you find yourself stopped for some reason, you are ready for an instant picnic.) Toy Haulers tend to be designed for dry camping, with big water tanks, and lots of storage. However, you have to haul out the toys and do the setup at every place you stop, and then reverse that, unless you get a big one with a dedicated bedroom.
Toy Haulers could make use of all the above ideas, except connection to the motorhome engine. (It's possible one could design a way to connect a tow vehicle and the trailer able to send 1kw or more but not too likely.)
For big trailers, which have electric brakes, it might be possible to make them easier to drive (and particularly easier to back up) with smart computer control of the brakes to torque-steer the trailer. For novices, backing up with a trailer is hard. I saw one system that showed you the trailer's path based on current wheel condition on your backup camera, which is a great idea.