Solar Power

Why Solar?

One’s first question may be, should I install a solar power system?  So I thought I would share why I to use solar power and how I decided on the design of my system.

From the time I first thought of living this RV life, I knew I wanted to boondock the majority of the time.  I find being in the wilderness a spiritually refreshing experience.  Hearing the sound of birds or other animals, the wind blowing, even the rain falling is what I love.  So for these reasons, I want to find remote boondock camps rather than camping in RV parks.  I wanted to be able to live without shore power indefinitely.

Following on from there, the next question was should I buy a generator?  The newer inverter generators from Honda, Yamaha, etc. are relatively quiet compared to the “contractor” type.  But they still are a machine noise intruding into the natural setting.  Then, they require a place to store, and the need to carry gas.  Also lifting the weight in and out of the truck or storage compartment would be difficult for me.  Considering these factors, I came to the conclusion that I did not want a generator.

Designing The System

This decision not to have a generator was the driving factor in the design of my system.  As a fulltimer, I plan to follow the weather, as they say.  Heading south for winter and north as the weather warms.  Even so, there will be periods when there are several cloudy days in a row.  My goal was to have enough solar panel watts and battery bank amp hours to be able to get through four or five days of overcast weather on battery power.  In addition I don’t want to be climbing up on the roof to tilt panels.  For these reasons, I chose to install a couple more panels than may have been necessary so I would have that extra cushion.

As far as my electric usage, I pretty much use whatever electrical items I want.  I use my coffee grinder and coffeemaker each morning, I watch movies as much as I want, have the laptop on whenever, charge all my devices, use the blow dryer, run my microwave, play music, etc. I have a 6 hp Shop Vac that I use to vacuum periodically.  I’m sure there is other stuff I don’t think of right now. 🙂  On a sunny day, the amps coming in usually exceed usage and the batteries stay at 100% charged.

To sum up, the system I have may be over-designed, but I like that I don’t have to worry about having power; and I don’t need to rely on a generator.  I suppose I could encounter a long enough period of cloudy weather that my batteries would be discharged to a critical level.  I believe this would be a rare event.  In such a case, I could reduce consumption to conserve the batteries, I could go to an RV campground for electric hookup, or move someplace out of the bad weather. 🙂

Also I should state that I will mostly be in areas of the west that have lots of sunny days – Colorado, Utah, Nevada, Arizona, etc.

As I began to research solar power there were a couple resources that I found very helpful.  Most important was Handy Bob’s Solar blog, www.handybobsolar.wordpress.com . Handy Bob is a retired electrical engineer and electrical product salesman.  He and his wife lived full time off grid in their RV for several years and did not own a generator.  Bob is a true pioneer in figuring out how to make RV solar really work.  If you want to understand the RV solar system, read all the pages on his blog until you understand the information he is presenting.  This will be the best thing you can do to achieve your goal of a well-functioning system. Bob is rather dogmatic in some of his statements, particularly on manufacturers. But the technical information he presents is excellent.

Another good resource is www.jackdanmayer.com .  His site has a page on RV Electrical and Solar.

System Components

Most of the components of my system came from AM Solar based in Oregon.   You can find them on their web page for current availability and pricing. Installation was done by Quality RV Solar in Fremont, CA, one of AM Solar’s affiliated installers.

Solar Panels

There isn’t enough real estate on my roof for 160 watt panels.  AM Solar has a very good high output 100 watt panel, the SP100 that is roughly 21”x42”. This panel fits well on my roof. I have five of these for total of 500 watts.  (There is also a 20W panel that came with the trailer.) This is where some may think I went overboard.  But I look at it this way.  I did not spend $800 or more to buy a generator, for which I would continue to spend money to buy gas for it. Plus I would have to endure the aggravation of the noise whenever I had to run it.  Instead I bought a couple extra panels to give me that cushion that I want for cloudy days. After the initial investment, there is no additional expense. My batteries seldom go below 90% state of charge.  This will also extend the life of my batteries.

Photo courtesy of Kevin Means

 Solar Charge Controller

 Blue Sky 3024iL 40A MPPT with IPN PRO Remote Monitor.  The charge controller is mounted in the storage compartment under the bed which is in the front of the trailer. Thus, close to the batteries. The remote monitor is mounted on a panel beneath the storage shelves next to the bed.

Batteries

 Lifeline GPL-4CT 220 AH batteries, total of four.  The batteries are on the trailer tongue in a rack I had fabricated by Carl’s RV in Tucson. I am very happy with the work they did. The four batteries provide 220 usable amp hours at 50% discharge.  However I would not want to discharge the batteries this low.  At this point the lowest they have been discharged is to 83%. This was after 3 days of rain/overcast weather.

Inverter

 I wanted an inverter that is large enough to power the microwave so I decided on the Samlex PST-2000 Pure Sine with remote control, which I purchased from Amazon.  It is also mounted in the storage compartment under the bed.  The inverter is not tied into the RV power system.  Instead I have a dedicated outlet in the kitchen/dinette area.  This is where I most always use 110v power.  So this works fine for me and I saved money on the installation by going this route.   At some point I may have it wired to the outlets and microwave; right now I don’t see the need to go to that expense.  The Samlex is very efficient.  Sometimes I forget to turn it off.  It goes into power saver mode after a period of non-use.  In power-saver mode it is only drawing about .5 amp.  With no load it draws about 1.5 amps in normal mode.

Wiring, location of components

After assembling all your components, one of the most important aspects of the installation is to correctly size the wiring.  This is the downfall of many installations; it is critical to make sure that your system wiring is sized correctly.  There is a voltage loss along the wire which increases with the distance of the run and the decrease in the gauge of the wire.  So the gauge of the wire must be sized correctly based on the length of the run in order to minimize this loss.  There are calculators on the web that will help with this.  Handy Bob discusses this at length on his blog, and I would recommend reading his posts on this topic.

Also the charge controller should be located as close to the batteries as possible, within 3 or 4 feet preferably.  However the batteries should not be in a compartment with any electrical components.

Other Equipment

One of the keys to successfully boondocking using solar power is to be able to heat one’s RV.  The standard RV furnace uses a lot of power (as well as propane).  Running the RV furnace will quickly deplete the batteries.  They are also obnoxiously noisy! Most boondockers look to an alternate source to heat their rig – generally some type of non-vented propane heater. These heaters don’t require electricity and operate silently. They are being used in hundreds of RVs, however one must read all of the operating instructions from the manufacturer and know how to use the heater safely.  Of utmost importance is properly venting the RV to allow sufficient inflow of oxygen.

After researching the different heaters available, I decided to purchase a Camco Wave 6 catalytic heater.  I have used this heater in temperatures down to 22° and it kept the trailer quite warm. The Wave heaters can be wall-mounted or freestanding.  My rig doesn’t have a good place to mount it, so mine is freestanding. I don’t run the Wave 6 at night when sleeping.  I light it when getting up in the morning and it warms the place up quickly.

I hope this information will be helpful to those considering a solar system. It is great to not be tied down to an electrical connection!