RV Energy saving devices include inverters, chargers and LED lights.

Besides our new refrigerator, a new inverter is one of our best RV energy saving devices.

Let us first explain what an inverter does for the neophyte if he is interested in RV energy saving devices.  When you dry camp (boon docking) there are no AC electrical outlets to plug your RV into for house power.  Most upper end motor homes and trailers come with a bank of large storage batteries.  Those batteries supply 12 Volts of DC power to operate things like lights and a 12 volt water pump.  However, if you want to run a refrigerator or a standard TV you must have a 120 VAC source.  The inverter fills that bill of providing 120 VAC to such appliances.  It does so by electronically converting the 12 volt DC power to 120 VAC.

The inverter must get its power from some source and that is the battery backup bank.  The battery bank likewise gets it power from another source called a battery charger.  That charger forms a major part of the inverter/charger unit.  Both sub-units convert energy from one form to another very efficiently.  That efficient conversion serves to meet everyone’s goal o f RV low energy camping if they are boon dockers.

A Magnum 12 volt 2800 watt unit also features a powerful battery charger to enhance our RV low energy camping experiences.

I purchased the Magnum 12 Volt 2800 watt pure sine inverter/charger which seemed to meet our needs.  When the unit charges the battery bank, it uses less energy than the old unit consumed.  It also takes less time than before when charging a deeply charged battery bank.  The new inverter also converts more AC energy out of the same amount of DC energy than the old unit required.  All this translates into having less need to run the generator as long.  It also means a lower energy bill when plugged into shore power.  The new Magnum inverter/charger design benefits from evolutionary technology advances.   Such is the honest capitalist advantage of constant profit seeking and competition.

I did not need to exchange the remote controller unit’s cable which was a blessing. That cable goes between the utility bay (where the inverter resides) and the bedroom wall.  I did have to  swap a couple connector conductor locations, but that was easy.  The cable pulling task actually frightened me.  The coach walls and steel obstructions can frustrate a cable puller tremendously.  The Magnum unit uses the same telephone cable as the Trace unit, but the conductors did need to be inverted. Fortunately, I was able to make the physical exchange of the two inverter units by myself.  All I did was to just take my sweet time and not hurry the project needlessly.  That work probably saved me about $400 of labor compared to if I had paid to have it done.

Our new all electric refrigerator operates only with continuous 110 VAC power available. We must therefore run the inverter off the house  battery bank while dry camping .  The inverter is always ready to supply 110 VAC power to the refrigerator whenever it calls for it.  The Magnum unit has a very low no-load battery current drain. That low drain also helps our RV low energy camping lifestyle.  Our battery/charger also handles other large but short-term loads simultaneously such as the microwave oven. We did experience extended periods of time between dry camping battery charges after replacing the inverter/charger.

 

Our RV house battery bank forms the foundation of  our RV low energy camping way of life.

We expanded our battery compartment a few years after our initial coach purchase. Afterwards the compartment accommodated twice as many golf cart batteries for longer dry camping between charges.  A few years later we replaced the old golf cart liquid acid batteries with eight new 12 volt AGM batteries that all had the same date code.  I knew at the time that I should have used 2 volt cells, but I could not find a size that fit the compartment.

IF you wire eight 12 volt batteries in parallel you are creating a potential problem.  The problem with paralleling several batteries is that they all have different impedance’s.  The smaller those differences, the less chance there is for shortening the life expectancy of the individual cells.  Some paralleled batteries act as chargers while others act as loads, creating a negative feedback condition.  Over time the batteries can no longer take a charge.  My theory is that one weak cell eventually shorts out which causes cells in other batteries to short and so on.

The answer is to use six of the largest 2 volt cells that you can find to fit in your battery storage space.  I wanted to find six two volt AGM batteries that would fit our battery compartment.  They did not exist.  Therefore, I purchased six Lifeline six volt AGM batteries that I wired in a series parallel configuration.  All the batteries displayed the same manufacturing date code which hopefully means that the internal impedance’s do not vary much.  We have not used the coach very much since installing the new batteries.  The batteries do seem to be give me the 12 kWh of energy I expected when I discharge them 80 percent.  The manufacturer assured me that discharging the AGM batteries that much will still give me enough re-charges to last me my lifetime if I don’t totally drain them  many times.

RV house lighting can drain more energy than you imagine.  New LED lighting options will help our RV low energy camping to be more pleasurable.

Our motor home features a significant number of lights throughout.  Many of those lights rob a great deal of energy from your limited battery storage system.  Incandescent light bulbs steal the most energy and needlessly so.  But don’t overlook your fluorescent bulbs in the ceiling, they too can be energy hogs.

The many incandescent and halogen bulbs can use a lot of energy over time.   I often forget to turn off my bay lights for days because they are unseen unless you open a storage hatch.  Replace bay lights, docking lights, porch light and some interior lights with LED bulbs and start saving now.  LED replacement bulbs typically use about one seventh the energy as their incandescent counterparts.

Fluorescent bulbs offer challenges to achieving RV low energy camping goals as well.

Our coach satisfies the interior lighting needs with a number of 18 inch fluorescent bulbs.  Those fixtures use (waste?) over 600 watts if left on all at once which happens too often.  I was astounded when I discovered how much energy those lights use.  For example, if we leave all of them on for ten hours we have just used up half of our total battery stored energy.

Fluorescent bulbs are of course more energy efficient than incandescent bulbs, but LEDs use less.  Fluorescents also have other disadvantages:

  • The ballasts inefficient, unreliable and not easily replaced
  • The brightness suffers in lower temperatures
  • The efficiency is not nearly as good as LED bulbs
  • A broken fluorescent bulb WILL emit highly poisonous mercury

We are now in the process of replacing our fluorescent and incandescent bulbs with LED bulbs.  It will take some time to find the right temperature (color) LED bulbs for our particular tastes and budget, but we will report our findings in updated blogs.  The prices and availability of LED replacement bulbs are improving by the month.  We should all utilize their advantages to improve our RV low energy camping gratifications.

Solar Panels and Charge Controllers can really improve the RV low energy camping scene.

My wife and I enjoy dry camping and I want to avoid having to run the generator to charge the house battery bank.  We have significantly reduced our energy needs by purchasing the new low energy refrigerator. I can only estimate our requirements at this time.  I estimate is that  we might require 3 or 4 kWh of energy on an average day.  However, some days we might require in excess of 5 kWh when it gets excessively cloudy and we use more lights.

Let’s consider having  a 6 kWh per day average electrical load.  We installed four Lifeline six volt 660 Ah 12 volt batteries in our battery compartment.  Those four batteries store about 16 kWh of energy, but only about 12 kWh can be utilized by discharging them 80%.  We should be able to expect 500 to 1000  eighty percent charge /discharge cycles from our AGM bank. That will give us about 12 kWh of real energy storage capability which is equivalent to about two average days between generator charges.    We could run the generator for perhaps four hours per day to keep the batteries nicely topped off.  If we did  that it would cost about $12 in diesel fuel (no wonder RV parks charge so much).  Most of us would rather not listen to the generator run instead of enjoying nature.

The above discussion should convince the reader that she should consider a solar answer to achieving an RV low energy camping goal.

Last year we purchased two Suniva 265 watt solar panels that I installed on our coach roof.  The NW summer sun travels almost directly overhead across the sky.  Therefore, we might expect to produce 530 watts of peak power at high noon under a clear sky.  Let us assume the average summer day gives us seven hours of average peak power.  Those two solar panels could produce about 3.5 kWh on a good summer day.  That much solar energy might run only our refrigerator for a couple days.  At least our generator would run much less of the time which can be worth a lot to us.

I also bought and installed a charge controller from Aims power last year. That controller will convert DC electrical energy from the solar panels into the correct DC voltage to charge our battery bank.  It performs this feat using very sophisticated computerized electronic circuitry.  The computer matches the solar output to the best match of voltage and current to charge the battery.  The battery charge level and simultaneous solar production level drive the charge controller’s output voltage and current levels.

Last summer I ran out of time before I was able to satisfactorily finish the installation of the charge controller.  Their application monitoring program would not work with my more modern computer.  They may never upgrade their application and that will sadden me if true.  There was also a problem with the charge controller shutting down before the battery could be fully charged.  With luck I will find the time to get these problems rectified.  If so, I will report back on my blog.