RV and Bus
Conversion Systems
A well designed renewable energy
system can provide many benefits to the RV or bus conversion
enthusiast. Among the benefits are:
1. Higher performance from the RV's
battery system and an extended battery life due to a more
controlled charging environment.
2. Less wear and tear on the RV's main
engine and or generator system when the house battery's
charging is supplemented by a solar or wind powered charging
system.
3. The ability to run regular
household appliances without having to listen to the constant
drone of a generator or having to stay at a RV park that
provides power.
4. A tremendous savings in fuel costs
from not having to run the RV's main engine or generator
system when the house batteries are in need of a charge.
5. Cleaner power that is free of
spikes and brownouts that can damage or shorten the life of
appliances.
These are but a few of the many
benefits that RV owners are experiencing with today's modern
RV specific alternative energy systems.
There are several different
configurations that are popular with today's modern RV.
The first is the DC Only System. In this type of system a
renewable charging source such as a solar array or small wind
generating system is used to maintain a charge on the house
battery or batteries. A house battery is a separate bank of
batteries which are dedicated for running DC rated appliances
and lighting. A house battery is kept isolated from the
starting battery so that if the house battery is ever
inadvertently drained it would still be possible to start the
RV's drive engine.
There are five key
components in a DC Only System:
1. A solar module or modules or wind
generator.
2. A mounting kit which permits the
solar module or wind generator to be mounted to the roof of
the RV or Bus Conversion. Solar modules are typically
mounted flat on the RV roof's surface. Solar modules can be
mounted on a rack that can be tilted which would provide some
additional performance but would require the RV to be parked
in a specific direction and would require the RV operator to
climb onto the roof of the RV to adjust the tilt angle. For
this reason most RV owners opt to mount their solar modules
flat.
3. Sunlight resistant wire, which is
specially designed wire, typically 10 gauge stranded wire
which has a protective sheath that is designed to withstand
many years of exposure to the elements without deteriorating
4. In the case of a solar module, a
charge controller is needed to prevent the over charging of
the RV's batteries and to prevent the batteries from draining
back into the modules at night. (In most cases a charge
controller is built into most small wind generators, so that
an external charge controller is not necessary. In most
installations, a wind generator is connected through a 50 to
60 amp fuse directly to the positive terminal of the
batteries.)
5. A protective fuse and fuse holder,
typically rated at 10 to 50 amps depending on the number of
modules that are mounted on the RV. The fuse should be mounted
as close as possible to the battery bank and connected to the
positive battery post.
The second most popular type of system
is the DC/AC System Without AC Powered Charger. This
type of system is exactly the same as the the DC Only System
except that an extra component known as an Inverter has been
added. An inverter is an electronic device that converts DC
electricity which is that type of energy that is store in your
RV's battery, into AC electricity which is the kind of energy
that is needed to run typical household appliances such as
microwave ovens, fans TV's, computers, power tools etc. There
are of course 12 volt DC rated appliances available but they
are typically much more expensive and much harder to locate
than standard 120V AC household appliances.
In addition to the
components listed above, there are three key components
involved in installing an inverter in a DC/AC System Without
AC Powered Charger.
1. A DC to AC inverter capable of
producing enough continuos power to run all of the appliances
that you might have running simultaneously. And a high enough
surge capacity to to start your largest inductive load such as
a motor, microwave or other load that contains a large
transformer or coil.
2. Inverter DC cables (positive and
negative) appropriately sized both in diameter and length. It
is recommend that an inverter rated at 12 Volts @ 1500 watts
or greater use a 4/0 (pronounced "4 ot") cable no
longer than 10 feet in length.
3. An appropriately rated DC fuse or
disconnect. Again the DC fuse or disconnect should be mounted
as close as possible to the positive terminal of the battery
as possible. Please note: Never use a fuse or disconnect in a
DC application that is not specifically rated for DC use.
Doing so can result in damage to your equipment as well as
having the potential for starting a fire !
4. An AC circuit breaker to protect
both the inverter's AC output as well as the loads that are
attached to the inverter. This standard AC type circuit
breaker should be mounted in between the inverters output and
the loads that are connected to the inverter.
Modern DC to AC inverters are very
reliable, quiet, and require virtually no maintenance. There
are two different types of DC to AC inverters in common use
today. The first is known as a modified sinewave
inverter. This type of inverter is very high in efficiency but
produces a waveform which is an approximation of the pure
sinewave waveform that is produced by the utility company. A
modified sinewave looks more like a squarewave that has been
time shifted in order to produce the energy content which is
found in power produced by the utility company. It's frequency
and voltage is rock solid which prevents the brownouts and
spikes typically seen with utility company power. Most
appliances such as TVs, Lighting, stereos, computers, inkjet
printers and power tools run find on modified sinewave power.
About the only appliances that you may see a problem with are
some Laser printers and some of the cheaper types of battery
powered tool chargers. In fact 95% of the inverters in RV's
today are of the modified sinewave type.
The second type of inverter is known
as a pure sinewave inverter and you guessed it, it
produces power that is exactly like the power which is
produced by the utility company without the spikes and
brownouts of course. This type of inverter produces pure
sinewaves, but at the cost of some efficiency loss and at a
much higher price. In fact most pure sinewave inverters are
typically priced at least 75% higher than their modified
sinewave counterpart and in some cases do not have as high of
a surge power capability than modified sinewave units.
The third most popular type of system
is the DC/AC System With AC Powered Charger. This type
of system is exactly the same as the DC/AC System
Without AC Powered Charger except that an extra component
known as an AC Charger Circuit with transfer switch has been
added. This type of system includes either solar modules or a
wind generator or both and their associated components and it
will include a DC to AC inverter as described above.
Only this type of system has the
capability of also charging your RV's batteries from a
generator or RV park AC power. It also has the capability of
passing the generator or RV park's power through the inverter
allowing you to operate your appliances while the batteries
are being charged ! The inverter that is used in this type of
system is known as a DC to AC inverter charger with
transfer switch.
In addition to the
components listed above, there is one other key component
involved in installing an inverter in a DC/AC System With AC
Powered Charger with transfer switch.
1. An AC circuit breaker to protect
the inverters AC input from the generator's or RV park power
output. This standard AC type circuit breaker should be wired
in between the generator or RV park power's output and the
inverter's AC input.
Important Never wire the
generator's AC output directly to the same point as the RV
park's AC output without using an external transfer switch.
Doing so will result in back-feeding and severely damaging the
generator with utility power or visa versa. Secondly never
wire the generator or RV park's power directly to the AC
output of any inverter. Doing so will result in damage to
your inverter and or your generator. Always wire the generator
or park power's output to the inverters AC input though
an external AC transfer switch.
You may be asking, "Why would I
need an inverter that works with a generator or park power
when I just bought solar modules or a wind generator ?"
Well, in one word "Weather". If your out on
the road and there's been no sun all week or there's no wind,
then it would be nice to have the backup option of running
your generator or plugging into park power for a few hours so
that you can run your appliances the rest of the day in peace
and quiet wherever you would like to go.
Solar module brands that are
recommended for RV applications: Really any brand module is
fine for RV use. All of the brands that Solar Home carries come
with sturdy aluminum frames and include with 25 year
warranties. Years ago monocrystalline cells were preferred
because they were slightly higher in efficiency but nowadays
due to technological advances there are polycrystalline cells
on the market that surpass the efficiency of their
polycrystalline cousins. For more of an explaination of the
difference between Monocrystalline and Polycrystalline solar
cells click here.
Inverter brands that recommended for
RV use: You can never go wrong with the Xantex line of
products which include Trace Engineering, Heart Interface and
Statpower branded products. Trace Engineering and Statpower
manufacture excellant sinewave wave products and Trace
Engineering and Heart Interface both manufacture the preferred
line of modified sinewave products.
Charge controller brands that are
recommended for RV use: Again Xantrex makes an excellent line
of charge controllers. Other preferred brands are BZ products
and RV power products both of whom manufacture maximum power
point tracking charge controllers which have the capability of
delivering up to 30% more power to the batteries than is fed
into the charge controller by the solar modules. Click here to
learn more about maximum power point tracking charge
controllers.
Let our expert staff technical help
you to design an RV system that's perfect for your needs.
Remember there is no charge for this service. Just give us a
call 1-888-955-3471 were here to help.
