RV and Bus
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
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
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
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 type of system 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
There are five key
components in a DC Only System:
1. A solar module or modules or wind
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
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
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 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
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 continuous power to run all of the appliances
that you might have running simultaneously. And a high enough
surge capacity 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 sine wave
inverter. This type of inverter is very high in efficiency but
produces a waveform which is an approximation of the pure sine
wave waveform that is produced by the utility
A modified sine wave looks more like a
square wave that has been time shifted and wave shaped 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 sine wave 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 sine wave type.
The second type of inverter is known
as a pure sine wave 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 sine
waves, but at the cost of some efficiency loss and at a
much higher price. In fact most pure sine wave inverters are
typically priced at least 75% higher than their modified sine
wave counterpart and in some cases do not have as high of
a surge power capability than modified sine wave units.
here to learn more about inverters.
The third 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
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 use: 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 explanation 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 Xantrex line of
products which include Trace Engineering, Heart Interface and
Statpower branded products. Trace Engineering and Statpower
manufacture excellent sine wave products and Trace
Engineering and Heart Interface both manufacture the preferred
line of modified sine wave 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
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.