Monday, September 8, 2014

Ok, Lets Talk About Toilets

This is nobody's favorite topic, but we need to plan for our toilet facilities.  A pet peeve of mine is the conventional RV Flush Toilet that makes no sense to me except that the manufacturers wanted to make it seem like you're in your home bathroom.  For any kind of self-contained camping,  it doesn't make sense to carry the extra gallons and weight in fresh water, and store gallons of black water you flushed in another tank.  Heck, we're trying to get our toilets at home to use less water so why are we doing this with our campers?!  I'm convinced the RV of the Future is going to leverage either composting toilet technology or ultra low volume cassette-type toilets to save water, weight, and hassle.

Cassette Toilets

You're starting to see more RV's go to a cassette-type system where the toilet and holding tank are one connected system. They use little water and the holding tank has wheels and a retractable handle so you just pop it out and dump it in a toilet or dump station.

Thetford makes the most popular ones and you often see these combined with a shower enclosure for very effective RV space utilization.

Composting Toilets
The off-grid movements started using composting toilets over 20 years ago and they have gotten progressively better and more popular. They are a self-contained toilet that works by evaporating liquids and composting solids. You don't need water, city sewer hookups, or a septic system. They're great for vacation homes and any water conservation application.  Sun-Mar are one of the original and most popular manufacturers.

Unfortunately these haven't been produced in a size and price range that was good for RV's though, until recently. Now there's a composting toilet design for marine use manufactured by Natures' Head that I think would be ideal for an RV.

The GearBox Toilet Choice
As I was designing my trailer I got carried away and I had a bathroom in it at one time.  When I scale it back to the current size, I really didn't have room for a separate bathroom.  If I was going to put in a bathroom, the marine composting toilet is very intriguing.  But in the end I'd probably go with the cassette toilet and combine it with a shower in the same space.  

For the GearBox, I'm going simple and space efficient, so I went with Thetford's Curve which is a higher end portable toilet.

These are a big step up from the tiny, square porta-potties, and its easy to separate the tank and dump in my home toilet. Amazon to the rescue again


Because of the growth of solar and other alternative energy solutions, there's been a lot of innovation in the DC power to 120V AC inverter industry.  I wanted a combo inverter / charger which converts 12V DC into 120V AC when you're travelling and not plugged in, and when plugged in to normal household current, it will convert 120V AC to 12V DC and charge the battery system. These modern electronically controlled inverters automatically sense if you're plugged in or not and will transfer over nearly instantly.  And they protect your battery bank with over / under voltage sensing 

Pure vs. Modified Sine

You will come across "Pure" versus "Modified" sine wave inverters when shopping.  Modified sine wave inverters have gotten much better in recent years and they cost quite a bit less, but one of the reasons they cost less is that they are not quite a perfect sine wave AC cycle like you would have with household current.  For some applications this is just fine, but for sensitive electronics and other types of applications they are not.  In applications where modified sine wave inverters are not suited for, they heat up and certain electronics don't function.  When I hear heat and functional problems, I hear inefficiency and from my dreaming about amps post that is the last thing I want.  So I narrowed my search to pure sine wave inverters.

There's quite a range of prices in the pure sine wave inverter field.  The best ones with the highest efficiency in the 2-3K Watt size were anywhere from $1200-$2400.   You can find very cheap ones on eBay for $500 but I would stay clear of those like the plague.   Do your research and I found both the Inverter Store and Inverters R Us to be good dealers who responded well to support and sales questions. 

As I was estimating my appliance power draw, unless I turn everything on it once at full blast, I really should be able to get by with a 2000 W inverter.  But that leaves little margin, I also happened to find a good deal on a 3000 W inverter with solar charge controller on eBay, in case I want to add solar panels later.  In talking with dealers I came across the Aims brand which seemed to be a decent compromise on quality and affordability, and is an established brand.  My GearBox inverter is an Aims 3000 Watt Low Frequency Pure Sine Solar Inverter Charger.  Amazon also has a similar one without the Solar Controller.