Monday, May 20, 2013

Boondocking Part 2: Power (The sky's the limit)

     Sometimes it is necessary, or even desirable to spend a night or two in a more developed, commercial RV park or campground for the amenities and to dump tanks or restock.  Our goal is to explore as much of the country camping away from more developed areas.  Such living off the grid requires the ability to gather energy and efficiently store it for as long as possible.  Additionally, portability was the primary factor as I designed this system. 
     We have converted all of the appliances and several amenities to an AC/DC setup including the TVs, DVD, and even added an Engel 43 quart fridge/freezer that draws remarkably little power.  We even switched from a 120v drip coffee maker to Coleman's on the stove propane powered drip maker.  We knew we would never be able to power our A/C or microwave oven off batteries as these would require incredible amounts of power/space.  For such requirements the Honda generator will come into play.  This is the most efficient generator on the market. 
     The RV Battery Bank is the "heart and soul" of every OTG unit.  It requires the most planning and cost.  This is no place to cut corners.  I researched this thoroughly on my own and talked with many other bloggers about their setups.  I knew I wanted to utilize a 6 volt series/parallel setup using deep cycle batteries.  This wiring design uses the more efficient 6 vdc battery in a configuration wired to represent 2 additional 12 volt batteries.  Series wiring for more power, parallel wiring for longer amp hours.  I went with Trojan T-105RE batteries, a new version of the traditional T-105s designed to be used in a renewable energy environment.  These batteries are a bit pricey, costing $700 for 4, but designed to last about 4000 cycles when discharges are kept to the 20% level.  I built a 4 battery setup utilizing 4 AWG interconnect cabling mounted in the back of the truck.  Cabling between the bank and the RV supply is 24 more feet of 4 AWG cabling.  This will provide us with nearly 585 amp hours of power.  At the 20% discharge level this amounts to nearly 24 hours of uninterrupted power without the solar panels. 
     I always knew we would begin with solar power.  There is a plethora of RV solar setups out there and the price ranges are wide as the Gulf of Mexico.  My best friend turned me on to a great starter kit from Harbor Freight This bank of three 15 watt amorphous panels mounts on a 45 degree portable frame and provides 45 watts of power at 4 amps.  This kit, complete with charge controller and cabling runs about $170 online.  Setup is about 30 minutes.  I have used these panels to power my RV battery for 3 years.  They do a good job keeping the single RV onboard Trojan 12vdc battery charged as long as discharge levels are kept to no more than 50%.  I built an additional 30 feet of cabling to enable placement of the panels further away if needed due to parking issues.
     With the advent of the larger battery bank this winter I added another set of portable panels.  This time I went with CEA Solar portable 130 watt polycrystalline panels.  This 2 panel setup comes in a high impact metal briefcase and sets up in about 5 minutes with adjustable fold out/tilt legs.  Again, I added another 25 feet of extension cabling.  The highly efficient total solar system now provides 175 watts of power at 7 amps, reducing my battery bank recharge time by 33%.  Total recharge time for a 20% discharge is about 11 hours daily. Price, of course, is higher;  I purchased these from the Quartzite RV Show on sale for $450.  The use of 2 setups allows for variable setup angles compensating for sun placement at different times of the day. 
     Any solar system depends totally on the availability and duration of clear sun power daily.  We all know this can be wishful thinking at times.  As such there will always be days where the battery bank will need man made help.  The Honda EU-3000 generator provides 3000 watts of power and will run up to 21 hours on a single 3 gallon tank of gas.  This will be used in tandem with the Deltran Battery Tender Plus System to top off the battery bank.  Some days the generator may be the only source of power, depending on weather.  OTG RV owners are always tinkering and experimenting one way or another and as such I may still add another 2 batteries to the bank and perhaps a portable Air-X Wind Turbine. 

No comments:

Post a Comment