Power for Dry Camping
Technical Issues and Projects
Full Timer Tutorial
RV Electric Power for Dry Camping
Read This Disclaimer First
I've written what I personally did, and my opinions. Don't assume what I
did was safe, and don't assume it will work for you. Do more research, and
make your own choices. I'm not responsible for your outcomes! :-)
Contents of this page
2. Why Dry Camping
3. Dry Camping Electric Overview
If you visit the Technical section of any RV forum
on the internet you'll soon see these questions
How many solar panels do I need to charge my
What size inverter do I need to run my microwave?
How many batteries do we need to dry camp?
After replying to several dozen of these, and similar
questions, I decided to write a "how to" guide for this topic. So, here goes...
One problem is that most people would like a simple
answer, but it just isn't simple. I'll try to write this as concisely as
possible, but there are many variables, and you'll need some minor technical
knowledge. So fair
warning, this isn't a short topic. I'll use links to
additional information on some topics. That way you can keep reading for the
basics, but you can click on the link if you want more detail.
I assume you have budget constraints -- you're not
rich. You need to learn as much as possible about the subject so you can
save money by doing most of the modifications yourself. Some things you
may not be comfortable doing yourself, but at least you'll understand them and
be able to evaluate quotes given to you by professionals.
Intended Use -- Frequency and
Duration of Dry Camping
If you plan to dry camp only 2 or 3 days at a time
you probably don't need any modifications. Most RV's are designed to do
this. However, if you'd like to dry camp more you'll probably want to make
You may have already thought of some lifestyle
changes you'll have to make to dry camp. One example is water
consumption. I imagine you've already accepted quick showers or sponge baths as a necessary
evil. Can't take those long hot showers with only 100 gallons of fresh
In the same way, you may need to make some
concessions on the use of electrical conveniences, because they require a lot of
power. Appliances that generate heat or cold are the top users of
electricity in any RV. Among the worst is the air conditioner system.
If you plan to run an air conditioner, plan to run a generator! One
exception is the "swamp cooler", used in dry climates. We have
one of these that only draws 5 amps DC.
Other big energy users are microwave, toaster, hair
dryer, curling iron, soldering iron, space heater, coffee maker, etc. To
use these items on DC power requires a large battery bank and a large inverter.
Otherwise, you really need a generator running any time you're using these.
The more you conserve electricity,
the less you have to worry about generating it,
and the less it will cost you in equipment.
So, how often you dry camp, for how long, and how
much power you use, will determine how extensive your modifications need to be.
I'll outline three "levels" of dry camping and give some general comments on each.
Later we'll get more detailed.
Why Dry Camping?
Why would you want to dry camp? There are many
reasons. For one, it's the only way to "Boondock". That is, to camp
away from everyone in the remote parts of the country.
Another reason is for economy. I'll use our
own budget for 2005 as an example. We've been fulltiming since September
of 2004 and dry camping nearly 50% of the time. At our current rate we
believe our solar and other equipment will have paid for itself sometime in
How we saved $2272.05 by dry camping in 2005
In 2005 we paid $3493.66 for campsites.
Out of 365 nights, 184 nights were DRY camping, and of those
184 nights, 113 were FREE
On average, we paid $15.80 per night for sites that
were Full Hookup
So, if we had paid for a FHU site every night, we'd
have paid 365 X $15.80 = $5765.71 for camping
By dry camping, we saved $2272.05 in 2005 (and a
similar amount in 2006, etc.)
Dry Camping Electric Overview
If you own a newer, high-end motorhome, you may have advanced monitoring
systems, generator auto-start, etc. Be sure to consult owners manuals
and/or your manufacturer before making any changes that might void your warranty
or damage your equipment.
Basic Dry Camping
Duration: 2 to 7 days at a time.
Generator and Batteries: If you have a
motorhome or other RV with a built in generator you may not require any changes
at all. Many people dry camp with only the equipment that came with their
At most, you'll need only a few things. The most common
modification will be to increase the number of batteries. For example, if
your RV has 2, add 2 more. This will probably cost under $200. The
benefit is that you'll reduce the frequency of generator runs for charging.
Note that if your batteries are old they'll pull down the new batteries, so you
may want to replace them all at once.
With this setup, you won't have enough battery power
to use the microwave, hairdryer, toaster, or other high wattage appliance, so
you'll need to run the generator to use these. But that's OK because
whenever the generator is running the batteries will be charging too.
Your RV probably has a device called a "Converter" that uses
120 Volt AC electricity to make 12 Volt DC. This 12 Volt DC powers all
your 12v lights, and 12v appliances like TV, radio, etc. It also charges
your batteries. It does this whenever you're plugged in at an RV park, and
also when the generator is running; however, the standard RV converter is a poor
battery charger and takes a long time to fully charge them. For this
reason, you may consider a dedicated battery charger that will charge the
batteries faster. Another alternative is an inverter/charger. Some
of you will already have one of these, especially in newer and higher-end
If you don't have a generator, or if yours is
loud and you hate to hear it run, you could buy a quiet, efficient generator
like the Honda or Yamaha models. We'll figure out later what size you should buy.
Cost starts around $500 and goes up.
Solar: For this amount of dry camping
solar energy is not cost effective; however, if you really hate the sound of a
generator, even the super-quiet Hondas, you might consider a couple of solar
panels (200 to 250 watts total) and a good charge controller. Still,
without a generator you still can't run your high wattage appliances. Also, you'll need to remember that the
panels have to be in the sun, so your home will be in the sun too, unless you
have the panels on remote mounts. This basic solar setup would cost around
$1100 to $1500. That's a lot to spend if you're only dry camping a few
days or a week at a time.
Inverter: An inverter is similar to a
converter, but it does the reverse. It takes battery power and turns it
into 120 Volts AC for running standard household appliances like vacuum
cleaners, TVs, computers, etc. Most newer motor homes come standard with
an inverter, so you may already have one. If you don't, you may not even need
one. It depends on your lifestyle choices and how your rig is equipped to
use DC voltage. If your TV, radio, lights, etc. are all 12 Volt DC, and
you don't plan on using any other appliances, then you can get by without an
$$ Total cost for basic dry camping: $0 to $2000.
Moderate Dry Camping
Duration: Multiple 5 to 7 day trips each year,
up to 30 days or more at one time.
Generator: A generator is almost a must
at this level of dry camping. Normally, a balanced system including a
generator and solar is preferred.
Even with solar power, you'll still probably need a generator from time to
time but maybe not if you're very frugal or only camp in sunny places, or have
lots and lots of panels.
Batteries are very important for this much dry
camping. Most people will consider the minimum to be 420 Amp Hours of
battery power. You'll get this with four golf-cart sized 6 volt batteries
(wired to make 12 volts). More batteries are better if you can afford the
space and weight.
Solar Panels can start becoming cost effective at
this level. A typical system (like ours) will have three 120watt
(360 Watts total) and a charge controller that maximizes panel output (called an
MPPT controller. This setup will cost between $1700 and $2200 if you do
Inverter: It depends on your
lifestyle, but most people dry camping this much need an inverter. A
pure sine wave inverter with 1000 to 2000 watts output is typical. Some of
these will also have a built in battery charger, and this can be a plus.
Adaptations to save power: You can do
with less capacity, if you can save power to start with. Replacing
incandescent lights with
fluorescent is one way - almost a must do. Choosing more efficient
appliances, and using more 12 volt appliances to avoid the inefficiency of the
inverter (generally you lose 10%).
Here's the update:
The Importance of Batteries
and Adequate Charging
After three years of dry camping, and watching others do
it, I've come to the
conclusion that the lack of an adequate battery bank is the #1 deterrent
to successful (i.e. frugal, fun, and quiet) dry camping. Your
batteries are the heart of your system, and if they are too small, or if you're
not fully utilizing them, you'll be a slave to your generator and the bane of
neighbors who would like to enjoy a little quiet from time to time.
Without the ability to store sufficient power to
meet your daily needs you're going to have to run your generator most of the
time, and that's costly, noisy, and totally unnecessary. We've seen people
who run a generator 8 to 12 and even 16 hours a day. There's just no
reason for that. With an adequate battery bank, a good inverter/charger,
and a little conservation, you should be able to meet all your energy needs by
running the generator just a few hours a day, even without solar power.
Your situation will vary, but here are the basics
for a non-solar RV:
Do the energy survey (in the next chapter "Determining your Needs") and determine how much power you'll
Buy more batteries so you have enough to meet your needs.
Ensure your charger will charge your battery bank at the highest level allowed
by the manufacturer (see the chapter on Battery Chargers for details)
Install an efficient pure-sine wave inverter to meet your basic AC power needs
for TV, Computer, etc. No need to power the microwave, toaster, hair
dryer, etc. You can start the generator for these.
Plan your battery charging.
First thing in the morning, note your batteries state of charge. If they
are below 50% write down how far below (let's say they're down 20 amp hours
Start the generator first-thing in the morning (as soon as quiet hours are over)
and start charging your batteries. Also, use this time to run other
appliances as needed - coffee maker, microwave, toaster, etc.. Don't turn off the generator until the batteries are
at 100%. This might take 2 or 3 hours, maybe more. It's also OK to take
them up to 95% 3 out of 4 days, then 100% on the 4th day.
Be frugal with power use all day. Turn off anything not needed.
Remove phantom loads. See Conserving Power and other
chapters for more tips.
During the day/evening, any time you run the generator to power the microwave,
etc. be sure to charge batteries too (assuming your generator will do
both at the same time)
Re-start your generator when your batteries reach 50%, or when they reach 50%
plus the previous morning deficit (see item 1 above). Be sure to charge
your batteries enough in the evening so they will NOT be below 50% the next
morning when you wake up.
Start over at #1 and repeat every day.
$$ Total cost $400 to $5000 if you do it yourself.
Add $400 to $2500 to have it done. A lot depends on what you start out
with in the RV.
Extensive Dry Camping
Duration: Up to full-time dry
camping 24/7/365; totally off-the-grid.
If you're planning on this you should have some
experience dry camping so you know what you're getting into. Depending on
your energy needs the same equipment used for "moderate" dry camping could
work for you, but often you'll want more reserve capacity and greater
flexibility. Our personal system is "Moderate Level" and we get by OK, but
as Tim Allen says, there's no such thing as too much power
Most long-term dry campers have larger battery
banks because it gives them more reserve capacity. It's also more
economical in the long run, because you're not draining the batteries as deeply
in between charges and they last longer. Some with high cargo capacity
(like bus conversions) have over 1000 pounds of batteries.
Some dedicated dry campers have gone to 24 volt
systems and industrial batteries. Higher voltage systems lose less
voltage in cable. Solar power is utilized as much as possible -- 700 to 1000 Watts or more isn't uncommon.
Much of this equipment is intended for home and industrial applications, and
inverters, chargers, solar panels, etc. are all 24 volt (or even 48 volt).
Depending on the geography, you'll sometimes see
wind power generators. These have
advantages and disadvantages. They work day and night, and it doesn't
matter if it's cloudy. Of course, they do need a stiff breeze to work
well. They're also a little noisy, some more than others, and they
sometimes kill flying birds.
$$ The total cost of a setup like this
can easily reach $10,000 DIY and more if done by a professional.
OK, that's the overview of dry camping power levels. Think
about where your plans fit in and let's figure out how much power you'll need to
reach your dry camping goals
Continue on to
Determining Your Needs -- or choose another topic from the menu in the left
sidebar at the top of this page.