One of the most useful items that you can add to your RV is an inverter. Inverters make 110 volt AC power from your 12 volt battery system. This will allow you to operate many of your appliances and accessories that require AC power without the noise and cost of operating a generator. Inverters range from simple portable units that plug into your cigarette lighter to larger, hard wired units that are permanently installed. AC wattage ratings are available from 100 watts up to 4000 watts or more. About the only thing that you won't be able to operate with a suitably sized inverter is your air conditioner... the huge size of the battery bank required makes it impractical. Most other appliances are fair game. Picking the right inverter isn't difficult. You need to decide just what it is that you wish to accomplish and how much battery capacity you have available.
Sizing. Let's start by determining what it is that you want to
operate. Here's a table listing some of the more common appliances and
their wattage requirements.
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It's obvious that your microwave requires quite a lot of power. Most ovens will draw 650 - 1000 watts. Starting surges can be as high as 1500 watts. If you want to be able to use your microwave with your inverter, your inverter should be capable of producing at least 1000 watts and be rated for a 1500 watt surge. If you want to be able to use resistance heated appliances, like a toaster oven or electric coffee maker, be sure that the inverter you choose has a high enough rating. Most of these appliances will require 1200 to 1500 watts. They don't have a starting surge, like motors or microwaves, but are hungry for watts. When in doubt, consult the owners manual for the appliance or check the ratings plate for wattage requirements.
Now is a good time to discuss just what these wattage numbers really
mean in terms of 12 volt battery power. First, we need to do a little math...
Hey, wait... come back here! I promise that it will be simple and won't
require you to buy a scientific calculator to figure it out! What we need
to do first is figure out how many DC amps the inverter will draw when
it's making that AC power for your appliances. Put simply, for every 100
watts of AC power that your inverter is producing, it needs to draw about
10 amps from your 12 volt battery system. For inverters rated at 90% efficiency,
the number is closer to 9.25 amps per 100 watts, but for ease of calculation,
just assume that 10 amps DC per 100 watts AC... it's easier to figure that
way and errs on the side of safety. For those of you who just MUST have
the math, here it is: Watts = Volts x Amps, so
Amps
= Watts / Volts. For an inverter, operating at 90% efficiency, the
conversion can be represented thus: AC watts / 12 volts X 1.11
= DC amps
Example... television drawing 100 watts operating on an inverter will
draw about 9.25 amps from your batteries..
100 / 12 X 1.11 = 9.25
The reason that this is important is that you only have a fixed capacity
in amp/hours available from your battery bank. A pair of 6v deep cycle
batteries or a pair of group 24 RV batteries will have a capacity of about
200 amp hours. That means that if you run that TV from the previous example
for about 20 hours, your batteries will be flat! 9.25A X 20 hours =
185 amp/hours.
Still with me? Good! Using the chart on wattage requirements and adding
our new-found knowledge of amp hours, lets take a shot at how many amp
hours of battery bank we need to supply us for a standard days use.
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Totals >
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You begin to see that putting in a larger inverter to run bigger loads will require you to have an appropriately sized battery bank and an adequate method for recharging it! You can't hook a 2000 watt inverter to a single battery and cook the Thanksgiving turkey in the microwave! You should get a feel for your intended inverter usage and take into account the size of your battery bank before selecting an inverter. In my personal case, I chose a 750 watt inverter to go with my 2 battery bank. I didn't have room or weight capacity for more batteries, so I went with a smaller inverter. It runs all my electronics, charges power tools, runs kitchen tools, but won't support my microwave or toaster oven. It was a good compromise for my situation. It was also a lot cheaper, as my inverter was about $500, compared to the $900+ that I would have paid out for a 1500 watt unit. And that brings us to the next topic:
Hybrid Systems. Often, it is more cost effective to purchase a smaller inverter to run the small appliances that you have and use a generator to power the more watt-hungry larger appliances, like the microwave and coffee maker. This will give you quiet power for most uses and minimize the wear and tear on your generator. If you can't manage a full sized battery bank and large inverter, this hybrid approach may work better for you. It is the approach that I chose to use, and it works well for me.
Inverter types There are 3 main types of inverters. Square
Wave, Modified Sine Wave and True Sine Wave. Let's look at the differences:
Square Wave inverters are the cheapest. They also
are usually the least efficient and will not run any of your electronic
equipment. The reason for this is that the AC waveform they produce is
very different from what you get at a standard wall outlet. Instead of
being a sine wave it is a square wave. These inverters are usually functional
for power tools and motors, but will not work with your TV or stereo. Definitely
not recommended!
Modified Sine Wave inverters are the middle of the
road. They produce an output wave form that is close to a true sine wave
and will work adequately with most devices, including TVs and computers.
You may be able to see some slight distortion lines on the TV or hear a
slight buzz on the stereo, but for the most part, these inverters provide
quite acceptable performance. One noted exception is that most laser printers
won't work properly with a Modified Sine Wave inverter. They are also middle-of-the-road
as far as cost goes.
True Sine Wave inverters are exactly that. They
produce a practically perfect sine wave output. These units will operate
even the fussiest electronic device, but they are much more expensive than
their cousins, the Modified Sine Wave inverters. Do you need one? Probably
not, unless you simply MUST have the best, or are trying to get a highly
sensitive piece of equipment to work in your RV.
Battery Charging. Many of the better inverters designed for RV use are also high quality battery chargers. This is an excellent option, as it allows you to get rid of that old, inefficient converter and enjoy faster, safer 3 stage charging. Most of the major inverter manufacturers offer this either as standard equipment or as an add-on accessory on their inverters. These chargers typically can deliver from 25 to 150 amps of charge current and run very well with generator power, allowing you to quickly recharge your batteries while out in the boonies. These 3 stage chargers will also not boil the water out of your batteries. Instead, they will bring them to full charge and then taper back to a true float charge... these units can safely be left plugged in continuously, unlike the standard converter found in most RVs.
Costs. You can expect to pay about $50 to $100 for a small portable MSW unit. RV designed units start at about $500 for a 750 watt w/charger and go all the way up to units rated at more than 3000 watts and costing several thousand dollars. Price increases with wattage ratings and capabilities. The best thing I can suggest is to do some research. Check the links listed below for inverter manufacturers and remember to size the inverter based on your real needs.
Project: Installing
an inverter. I'm going to take you through the inverter installation
that I did for my RV. Your needs and situation will be different, but this
should give you some ideas. A word
of Caution: Always follow the inverter
manufacturer's installation guidelines, paying close attention to proper
wire sizing. Installing an inverter requires understanding of safe electrical
practices and electrical safety code. If you don't have the necessary skills,
get a qualified electrician to do the wiring. Don't take chances
with safety!
Mount the inverter in a compartment where it
will be accessible and safe from moisture and flammable items or gases.
Inverters utilize some components that can create a spark, so never
install an inverter in the same compartment as the batteries! I installed
mine in the forward compartment underneath the 5th wheel overhang.
Click Here for a bigger picture.
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Sources. Here are some links to Inverter manufacturers and retailers.
In particular, RV Solar Electric's website is well worth a look. They are
a very knowledgeable company and have been doing RV systems like these
for years. Their prices are very competitive as well. I bought my inverter
there and they were very prompt and helpful... give them a look!
Trace Engineering. (360) 435-8826. www.traceengineering.com
Heart Interface. (800) 446-6180. In WA (206) 872-7225. www.heartinterface.com
EXELTECH. (800) 886-4683. www.exeltech.com
STATPOWER. (800) 670-0707. www.statpower.com
RV Solar Electric. 14415 No. 73d St., Scottsdale, AZ 85260. (800)
999-8520. www.rvsolarelectric.com
West Marine. Box 50050, Watsonville, CA 95077. (800) 538-0775.
www.westmarine.com
Wrangler Power Products. These folks don't sell inverters, but
carry a huge selection of the wiring products you'll need to install one...
4444 S.E. 27th Ave., Portland, OR 97202. (800)962-2616. www.wranglernw.com
For even more detailed information on inverters, go see Phred
Tinseth's Inverter Poop Sheet on the subject. Phred will give you
a lot of great (somewhat opinionated) information on the whole process
of choosing an inverter. Well worth your time if you're thinking of installing
one! Also, stop by and read some of his other Poop
Sheets... Phred is a fine source of information and he has many
articles on a variety of RV related topics. A very useful resource for
all you Rvers out there!
A big advantage for those of us who spend some time away from hookups is the addition of one or more solar panels to the roofs of our rigs. Solar panels will provide power to charge your batteries whenever you have sunlight. This can extend a dry camping period almost indefinitely and solar is quiet and non-polluting. Even a single panel will help a lot. I have a single 55 watt panel, and it provides almost 6 amps of charge current when in direct sunlight. That doesn't sound like much, but multiply that 6 amps by 10 hours and you're doing some serious battery charging! Several solar panels, a good sized battery bank and an inverter will provide you with many of the luxuries of hookups and will be silent and reliable. The only drawback to solar is it's cost. A single 50 or 60 watt panel can cost you as much as $400 and larger panels are really pricey... still, it's an attractive option for those who like to spend a lot of time drycamping. A solar system consists of one or more solar panels connected through a charge controller to your RV 12 volt system. Sunlight striking the panels generates power and the charge controller monitors the battery voltage to prevent overcharging. These systems are extremely reliable and maintenance free.
Sizing. The number and size of solar panels may be determined more by your pocket book than any other factor. For all it's advantages, solar remains very expensive. It is definitely worthwhile to have at least a single panel, at least 30 or 40 watts, just to keep your batteries up in storage. A single 50 or 60 watt panel will, in the summer, provide you with as much as 60 or 70 amp hours of charge per day. For those who want to be truly hookup independent, a number of larger panels coupled to a larger battery bank will provide you with plenty of power, even when you have an occasional cloudy day. Cloudy days are the bane of solar charging! Even a high thin cloud layer will cut your charge current by 50% or more, and you'll only get 10-20% of rated power on an overcast day. This is when more panels will help. Most authorities agree that if you calculate your daily average energy usage and then provide enough solar capacity to exceed your daily use by 25%, you'll be all set. Let's think about that a little... If you take that daily usage table that I did for the inverter section and add the calculated additional 12 volt appliance and lighting use, we can come up with a figure to work with... see below
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Total >
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Looks like we'll need to replace about 140 amp hours (AH) of usage every
day. If we figure that a 60-75 watt panel can produce 60 to 70 AH per day
under perfect conditions, then it's reasonable to assume that the same
panel will produce an average of about 35 AH per day, due to adverse weather
conditions, time of year and other factors. Some days are sunny, some are
cloudy..... For planning purposes, we can figure on that average output,
per panel, of about 35 AH a day. Looks like we'll need at least
4 panels up there, and probably would be better off with five panels. There
is always some loss of efficiency when recharging a lead acid battery and
a couple of cloudy days will really hurt your overall charge capability!
Looks like we will either have to conserve power a bit better, or do some
serious investing in solar panels. The truth is, the above example is a
bit on the energy extravagant side, but illustrates that it's easier to
use power than it is to replace it! My own small system, consisting of
a single 55 watt panel, provides adequate power to keep me in business
for a week, provided that I am conservative and don't have cloudy weather.
If it's cloudy, or I have poor exposure to the sun, I have to run the generator
for a couple of hours every few days to charge the batteries.
There are a number of very good sizing guides available
on the web... RV Solar Electric
has one you should look at... click
here to check it out... Or consider their Rule of Thumb: "The average
RVer, one without unusual needs, generally finds that one 4 amp panel
and one 105AH battery (or equivalent) per person provides an adequate system
for long term outings. An extra panel and battery provides insurance during
bad weather and enough power to handle the unexpected."
Hybrid Systems. Again, sometimes the best answer is a compromise... a small solar system to save $$ on panels and a small generator to take up the slack when needed can be the most cost effective way to go. I have an Onan Microlite 2800 Watt genset... it'll just barely run 1 roof A/C unit, or anything else in the rig and uses very little gas. In the summer, with good exposure, I can go a week easily without hookups, using the genset only rarely. It's an approach that you should consider....
Mounting. If you're going to put solar panels on your RV roof, you will be faced with several problems... the mountings must support the panels safely and must hold them on the roof in the face of 70 MPH + winds. It is also preferred that the mounts don't cause your roof to leak! There are several types of panel mounts that have been designed with RV use in mind. Use them! If you do design your own mounts, make sure that they are capable of keeping your panels attached securely to your RV. Some of the available mounting systems provide for tilting the panels in one direction to allow you to maximize output by facing them directly at the sun. Since they only tilt on one axis, you will have to orient your rig to take advantage of this... not always possible. One school of thought is to mount the panels flat on the roof and simply use more panels to make up for the lack of efficiency. I chose to design my own mount for my one panel, using a full length hinge along one side of the panel and a standard crank up TV antenna assembly to provide for tilting the panel. I can crank up the panel from inside the rig to the best available angle and lower it flat to the roof for travel. This arrangement has worked well for me, and the panel is still up there after more than 50,000 miles. The panel is mounted to take advantage of the 5ver's roof line and gives me a wide range of tilt angles.
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Wiring. Now that your panels are on the roof, it is necessary to get all those electrons from the panel to the battery. Best suggestion is to use as heavy a gauge of wire as possible to reduce losses on the line over distance. Even though my panel maxes our at under 6 amps, I used 10 ga. wire to connect it. Bigger (within reason..) is better! Another problem is how to route the wires into the RV. Drilling holes in the roof is always to be avoided when possible, and it just so happens that most RVs offer some convenient alternatives. If your panels are near the refrigerator roof vent, route the wires down through the roof vent opening and into the interior of the rig. It's also possible to use a plumbing vent. For my installation, I used the black water tank roof vent pipe as a conduit.
Controllers. Although it is possible to directly connect the solar panel(s) to the batteries, it is much better to use a charge controller. This device protects against overcharging of the batteries and also provides a diode to prevent reverse current flow to the panel at night. These controllers can be as fancy as your pocketbook can handle, or very simple. The simple ones will usually cost in the $50-$75 range and do the same job as the fancy ones with the meters and computer monitoring. The controller simply hooks into the charge wiring between the panel and the batteries.
Sources. Here are some links to a number of suppliers of
alternative energy systems. Browse some of these sites to get a feel for
what's available, costs and applications. Several of these sites have guides
to help you design and size your own solar electrical system.
Home Power Magazine: PO Box 520, Ashland, OR 97520. (800) 707-6585.
www.homepower.com
RV Solar Electric: 14415 N. 73d St., Scottsdale, AZ 85260
(800) 999-8520. www.rvsolarelectric.com
Real Goods: 555 Leslie St., Ukiah, CA 95482-5507. (800) 762-7325.
www.realgoods.com
Backwoods Solar Electric Systems: 1395 Rolling Thunder Ridge,
Sandpoint, ID 83864 (208) 263-4290. www.backwoodssolar.com
Alternative Energy Engineering: Box 339, Redway, CA 95560 (800)
777-6609. www.alt-energy.com
Sierra Solar Systems: 109 Argall Way, Nevada City, CA 95959
(800) 517-6527. www.sierrasolar.com
Most RVs come standard with a little analog battery meter or a small LED display. These meters aren't very accurate and aren't much use if you really want to know what's going on in your 12 Volt system. One possibility is to purchase a good quality hand held digital volt meter and use it to monitor the voltage from your batteries. The drawback to this method is that you have to hook it up to your batteries whenever you want to take a reading. A better solution is to install a small digital panel meter and permanently connect it to your batteries. This way, the information is right there at your fingertips. There are a number of these battery monitors available. One place you can look to see some examples of what's available is at the Backwoods Solar Electric Systems website. Click HERE for a look at one of their catalog pages featuring meters. Most of the solar equipment retailers offer a variety of meters to suit your needs, but they can be a little pricey. Still, for an out-of-the-box solution complete with installation instructions, they're hard to beat. You can expect to pay $40-$50 for a simple panel voltmeter and as much as several hundred bucks for a really sophisticated system monitor. At the bare minimum, you should have an accurate voltmeter... even better is to have a voltmeter to monitor your battery's state of charge and an ammeter to see what kind of current is going to or from your batteries.
Some of you may be thinking: "Why should I have to pay such close attention to my batteries? Can't I just sort of ignore them and hope for the best?" Well, sure you can! The problem is that when you're dry camping and dependent on your batteries for all of life's little conveniences, it's real easy to use more juice than you put back in... sort of like overdrawing your checking account. The addition of a volt and amp meter will allow you to see how much current you're taking out of the batteries and how much you are putting back in via solar or generator charging. When I installed an ammeter, I was amazed at how much current just a few lights draw, not to mention other 12 Volt items like the furnace and water pump. It's definitely better to know for sure what's going on.
If you plan to install, or have already installed an inverter, you may be able to purchase a very nice monitoring panel as an accessory to your inverter. Most of the major brands designed for RVs have this option available. It can tell you all you need to know and some even have provisions for outside source charge monitoring, from solar panels, for instance. It's worth checking into and will save you having to install your own monitoring system. See the links above in the inverter section and check out some of the manufacturers webpages.
One alternative for you tinkerers out there is to build your own! Simple, battery operated DC panel meters are available for under $10 and with a little work, you can have a very nice 12 Volt panel meter for cheap! A little more work and you can cobble up a very functional volt/amp meter. Let's see how:
Project. Build a simple DC Voltmeter for your rig.
This is a simple volt meter that is easy and cheap. The meter runs off
a single 9 Volt battery and is very easy to build and install. You can
connect it to just about ant wiring in the rig that carries unswitched
12 volts and it's small enough to fit just about anywhere. The parts as
listed are available from All Electronics Corp. They have a website at
www.allelectronics.com
and you can download their catalog in PDF format and view it.
- Parts list
- 3 1/2 digit digital voltmeter, panel mount, battery operated, 200mv full scale. Can be purchased for about $10 from All Electronics Corp. 1-800-825-5432 Part # PM-128
- Small toggle switch, SPST, pick up anywhere, Radio Shack, your junk drawer, etc. All Electronics Corp. Part # MTS-4 will do just fine.
- 9 Volt Transistor radio battery.
- 9 Volt battery connector. All Electronics Corp. Part # BST-8
- 1 100 Kohm resistor 1/2 watt 0.5%
- 1 9.99 Mohm resistor 1/2 watt 0.5 %
Follow the directions included with the panel meter. The resistor
values listed above are the correct ones for the meter available from All
Electronics Corp., but your meter may specify different values to use.
The resistors are installed in holes provided on the meter circuit board
to form a voltage divider to set the range of the meter to 0-20 Volts.
The meter instructions will explain how to do this. Attach the battery
connector as specified in the meter instructions. Install the small toggle
switch on the battery connector + lead... this is used to turn the meter
on and off. You can omit this switch and have the meter on all the time,
but it will run down the 9 Volt battery in about 6 months. I chose to use
the on/off switch on mine. Mount the meter in your rig in a convenient
location, preferably near a 12 volt source. Closer to the battery is better,
but not super critical. Connect the meter input leads to the 12 volt source.
A fuse would be a good idea if the circuit that you connect the meter to
isn't already fused. A 1 amp fuse will be way more than enough, as the
meter draws practically no current. See below for a diagram.
This is a little more difficult, but worth the effort. The same meter as was used above can also be used to measure DC current if a device called a Shunt is used. Put simply, a shunt is a very accurate, very low Ohm resistor that is placed in the DC positive line directly off the battery. By measuring the voltage drop across the shunt, we can determine the amperage flowing thru it.
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Click HERE for a bigger picture
When I designed my monitor panel, I wanted to have everything in one
location. The panel has controls for the generator, the volt/amp meter,
controls and indicators for the solar panel and a handy 20A cigarette lighter
socket with a circuit breaker for heavy duty 12 volt loads. Whether you
buy one or build one, it's really worth your while to have at least an
accurate voltmeter in your rig to allow you to keep tabs on your battery
condition while dry camping. It will extend the life of your batteries
by preventing too deep a discharge and will give you the ability to see
just how much power you are using and putting back in. Prevent those "bounced"
energy checks!! ;-)
Most of the 12 Volt wiring in RVs is done using 12 or 14 ga. twinlead. The most common seems to be white with a black trace to denote the positive wire. When in doubt, check with a meter to determine which is positive and which is ground. A lot of RVs also use a crimp style connector to tap into these 12 volt wires to hook up lights and other low current devices. I don't personally care for these crimp connectors as they can fail over time, so any time I make a new connection, I use either wire nuts or solder and heat shrink to make secure connections.
If you intend to install 12 Volt equipment in your RV, it's important to be sure that you use adequately sized wire to meet the amperage requirements of whatever it is that you're installing. Here's a table of wire sizes and amperage ratings that will provide some basic guidelines. This table leans a bit towards heavier wire than is absolutely necessary, but that's actually safer in the long run. Always provide fuse protection of any new wiring that you install. The fuse should be sized so as to protect the wiring from meltdown. Don't put a 20 amp fuse on a circuit wired with 16 ga. wire.
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Last but not least, find your RVs 12 Volt Fuse Panel. It could be anywhere.
Once you've found it, make a note of the type and sizes of fuses used and
go get some spares. Many common fuses found in RVs can be purchased at
any automotive parts store. Spares, of the right sizes will come in mighty
handy if you should blow a fuse down the road, and having the right size
replacement fuse available will hopefully keep you from improvising a temporary
replacement (bailing wire) or substituting a larger rated fuse than the
one that's blown (very similar to bailing wire!).
Most RVs use simple incandescent light fixtures. These work fairly well, but draw quite a bit of current per bulb. The most common bulbs used are 1073 or 1141 automotive bulbs and they draw about 1.5 amps a piece. Many RVs can benefit from the installation of additional lighting, to help brighten up dark areas or illuminate work areas. In some cases, the existing light fixtures can be moved around or exchanged to provide lighting that better suits your needs. Incandescent fixtures are inexpensive and can be found in any RV supply store or catalog. Although they are inexpensive, when adding new lighting, it is worthwhile to consider alternatives to those standard incandescent fixtures.
Fluorescent lights are excellent for producing large amounts of light for less current. Sunray and Thinlite both make high quality 12 Volt fluorescent lights in a variety of sizes and configurations. These make great kitchen and workspace lighting. They are a little pricey, at $30 - $40 a piece, but work well and last a long time. Avoid those really inexpensive fluorescent fixtures found in some automotive catalogs... they produce rather bluish light and tend to use up tubes at an alarming rate.
For more efficient use of power, consider adding halogen lamps where possible. These fixtures deliver excellent white light for reading or detail work and use about 1/2 the power of standard incandescent lamps. I'm particularly fond of the lamps that Sunnex offers. I have one near the bed for reading and one by my recliner. Sunnex has a web site and an online catalog Stop by www.sunnex.com for a look. These fixtures are a bit expensive, but well constructed and are flexible to allow them to be adjusted easily for best effect. Click HERE for a picture of a Sunnex lamp.
There are many 12 Volt appliances and accessories you can buy for your RV. Some work very well and others are basically a waste of time. In my experience, anything that uses resistance heating to accomplish it's goal is a pretty sure bet to be a loser. A good example are the 12 Volt coffee pots you will see advertised in some RV catalogs. Trust me on this one.. they don't work. You will use up lots of battery power for very little result. The main reason is that these items were designed to be used in a vehicle with the motor running, so they are real energy wasters. Ditto on things like 12 volt frying pans and 12 volt toaster ovens. Just don't waste your money. On the other hand, there are a number of 12 Volt devices that will actually improve your quality of life, whether you're plugged into shore power or not. Here are a few of my personal favorites:
 |
Definitely a great addition to any rig... a "Fantastic Fan". This is
a high volume 12 Volt fan that replaces one of your existing roof vents.
It draws very little current and can really help keep the rig cool without
using the A/C. On low, it only draws a couple of amps and on high, it will
exchange the air in your rig for cooler outside air in a minute or two.
Find them at any camping retailer... Try:
www.camperschoice.com www.campingworld.com Adohen Supply Co. |
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These are great little fans as well... they run on 12 volts and move a lot of air for only about a 1.5 amp current draw. A couple of these, strategically placed around your rig will keep you a lot cooler! Find them at camping stores or lots of automotive parts stores. |
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If you have some 12 Volt Cigarette lighter outlets around your rig, one of these small automotive map lights is a handy addition! I use one to light my computer desk and it's great for providing light to type by without a big battery drain. They are also handy to use as night lights and can be removed and stowed when not needed. |
All right... we've got our battery bank squared away, figured out our charging sources, maybe installed an inverter and are all ready to spend a week out in the wilds, far away from the RV park campers with their convenient hookups. Great! Here are a few tips on how to make life easier for you and your own power company that's contained within your RV. The whole trick to successful dry camping is conservation. I don't mean huddling around a single flashlight to save battery power... I mean fully utilizing all the functionality of your boondocking home without running out of energy before you're ready to leave. Practice makes perfect, and as you get used to how your system works, you'll feel more confident being electrically independent.
- First off, start out with fully charged batteries.
- Turn off lights when you don't need them.
- Turn the radio off when you go outside.
- Pay attention to those things that draw power and shut them down when you're not actually using them.
- Watch the battery meter and get a feel for how healthy your batteries are. Refer to the tables from the 12 Volt Side of Life part 1. If possible, recharge your batteries before they get down to 50% of capacity, as this will extend their life.
- If you are using solar panels, pay attention to what's overhead. Park your rig so as to take the best advantage of the sun given where and how your panels are installed. In my case, with my installation, I try to set up so that the rig is headed due south, especially in the winter.... that takes advantage of the angle that my panel can be elevated on.
- Take advantage of the current that your solar system generates during the day and run high current devices then... charge your laptop batteries with the inverter for later use, take showers and such , etc.
- When operating on the inverter, beware of phantom loads! Here's a possible scenario: You turn on the inverter to run your computer. That's fine, but if your TV set and satellite receiver are still plugged in from last night, chances are they are still drawing power. This increases the amperage draw of the inverter and can run down your batteries much faster. My Satellite receiver draws exactly the same amount of power whether it's on or "off". My 13" TV draws about 50 watts when it's on and about 12 watts when it's "off". Pretty sneaky, huh? One answer is to put inline switches in the power cords of offending devices. Or, you can simply unplug them.
- When you run your generator to charge your batteries, why not run an electric heater too, if it's cold or the A/C if it's hot... you're running the genset anyway, right? Or, conversely, if you run your genset for making coffee every morning, your batteries will get a boost of charging right when they need it most... after a long hard night of supplying power for lighting, etc.
- If you like to dry camp in colder months, you are almost going to HAVE to get a catalytic or radiant propane heater. That forced air furnace that comes standard in most rigs draws 5-7 amps whenever the blower's running. That adds up in a hurry and will leave your batteries severely run down after a couple of cold days. Plus, those furnaces barely approach 60% efficiency, meaning that a lot of your expensive propane is being used to heat the great outdoors, instead of your rig. Check into a catalytic space heater... 95% or better efficiency and no battery drain.
- Pay attention to your batteries. Maintenance and proper selection pay off in long life.
- Provide for adequate charging and monitoring. Don't just "plug it in and forget it".
- Consider an inverter... they add a lot of convenience to your RV, even if you don't dry camp all that much. Make an intelligent choice based on your needs and battery capacity.
- Consider adding some solar charging capability to your rig. Do your homework and remember: the best thing about solar is that it's modular. Buy some now, expand the system later, you don't have to buy everything all at once.
- A good monitor panel will make your life away from hookups much easier. Plus, they're fun to play with! Whether you make your own or buy a fancy one, it will give you total control over your own power company.
- If you choose to upgrade your RVs original equipment, or add new accessories, follow good wiring practices. Just because it's only 12 volts doesn't mean that you can do a half-assed job. Use proper wire, of the proper size and fuse new circuits to protect against overloads.
- After all this work, take time enjoy the freedom that electrical independence can bring. Explore some of those more remote spots. Spend some time at Quartzsite or at the rallies and Escapades and never miss that electrical outlet! And most of all, don't ever let that 12 Volt electrical system intimidate you again.... Knowledge is Power, and with your knowledge, you should have plenty of power, no matter where you park!
