Wecome To RVs and OHVs

This blog is all about RVs (recreational vehicles) and OHVs (Off Highway Vehicles), camping, and survival
and how they work together to provide wholesome family fun and great learning opportunities.
Many posts are intended to familiarize novice campers and RVers with RV systems and basic camping and survival
skills. But even experienced RVers and campers will enjoy the anecdotes and may even benefit from a new
perspective. Comments, questions, and suggestions are encouraged.

Friday, October 17, 2014

Trade Offs

There are many trade offs to take into account when considering a camping lifestyle.   One of the first decisions is whether you like any kind of camping.  Next is whether you want to tent camp or camp in some kind of RV.  While cost is often a major factor in deciding between tent camping and buying an RV, it certainly isn't the only factor.  Tent camping can be done in a wide variety of locations.  It also gives a more primitive, adventurous spirit to outings which can be very satisfying, even if not as comfortable as an RV.  RV camping provides better protection from the elements along with significant creature comforts that can rival residential environments.

If you choose tent camping, one of your biggest choices will be what kind of tent to buy.  If you have a large family you will need a large tent.  If, on the other hand you plan to do a lot of backpacking, you'll need a very light weight, compact tent.  I've used 10'x14' cabin tents for family camping and a tiny little back packing tent that is really little more than a sleeping bag cover for solo back packing.  Each one is equally enjoyable in its proper environment.

If you decide you'd like the additional creature comforts and security of camping in RV, you'll need to do some research to figure out what kind of RV will work best for you.  There are many options, ranging from relatively inexpensive tent trailers with minimal facilities to huge luxury RVs with amenities that rival high-end residential homes.  Budget may be a significant factor for most people, but intended use and desired lifestyle will also play an important role.  You will need to decide if you want a self-propelled RV (motorhome) or a towable (trailer).  Another option is  truck camper.  There are advantages and disadvantages to each type.  Trailers are usually less expensive, but you also have to consider the cost of a tow vehicle unless you already have a vehicle capable of towing your chosen trailer.  There are many trade offs in choosing between the various options within each category.  Motorhomes range from Class B van conversions that are essentially the same size as a regular full size van, to Class C's, built on a cutaway van or truck chassis, to large Class A units that resemble large buses and, in fact, are sometimes built on bus chassis.  Trailer options begin with small tent trailers and can range up large fifth wheels measuring 35' in length or more.  In between are a variety of "bumper pull", goose-neck, and fifth wheel trailers. Bumper pull trailers use a standard trailer hitch that is usually mounted below the bumper.  Goose-neck trailers have a trailer ball mounted in the middle of a pickup bed.  Fifth wheel trailers connect via a special hitch similar to those used by large semi-trailers, which is also mounted a pickup bed.  The towing characteristics of each type of hitch will be somewhat different so you'll want to research the handling and load capacities and, if possible, try out any options you want to consider BEFORE you buy.  Truck campers allow you to remove the camper from the truck when it is not in use and use the truck for other tasks.  Truck campers tend to be less spacious than motorhomes or trailers and are usually more top heavy.  If you live in a state where there is a lower speed limit for vehicles towing trailers (such as California), you may want to consider whether you can live with longer travel times.  The argument for differential speed limits is based on the assumption that large vehicle are safer at lower speeds and ignores the more pragmatic and scientifically proven "85 Percentile" approach, which recommends universal speed limits should be set to the speed 85% normally driven on a given stretch of road.  Consistent traffic speed has repeatedly been shown to be safer than situations involving "traffic sheer" (different speeds in different lanes, known to be one of the most dangerous practicies), yet many states continue to post differential speeds, thereby creating traffic sheer.

Once you have decided on what type of RV you want, you're likely to face many more tradeoffs before you finally select a specific vehicle.  Some of the normal issues you will face will include new versus used (usually determined up front by budget), age or mileage versus luxury features (you may be able to get luxury features you want and stay within your budget by buying an older model), power versus fuel economy (if you need to tow a boat or OHV trailer  you'll want more power and will probably have to sacrifice fuel economy to get it).  Whether you opt for an older model to get more features or a newer one to minimize mechanical risk and potential maintenance cost, will depend on how badly you want the features and what resources you have (skill, tools, money) to handle additional maintenance.  Some other considerations may include intended use:  do you plan to stay mostly in campgrounds with full hookups or will you be doing a lot of "boondocking"?  Class A motorhomes generally have larger fresh water and waste water holding tanks than Class B or C units and allow you longer boondocking stays.  Class C motorhomes, oddly enough, often offer bunkhouse configurations that provide more beds and may be better suited for large or growing families.

Where you are in your life may be a significant factor in making tradeoffs.   Having a young family will obviously swing things in favor of "bunkhouse" motorhomes with lots of sleeping capacity and room for growth.  And older couple may favor more conveniences and more luxury.  RV manufacturers know this and you'll find that those huge, high end, luxury coaches are often designed mostly for two people.  A young family may want to favor a late model low mileage unit.  An older couple may choose to spend the same amount of money to get an older coach with more amenities.  The longevity and resale value may be more important and of more use to a younger user while comfort and convenience may be more appealing to an older couple.

You may want to consider whether certain accessories or features are essential in your initial purchase,  or whether you can add them on later.  Some features, such as slide-outs, are not practical or cost-effective to add on to existing vehicles.  Things like hydraulic levelers are pretty costly and usually require expensive professional installation.  If you're a moderately good handyman and have the right tools and equipment, you may be able to install awnings yourself and anyone with basic mechanical skills can add wheel simulators to improve the appearance of a rig with uncovered steel wheels.  Likewise, you can probably add or replace a microwave oven or TV without too much expense or difficulty, but replacing a refrigerator is a much bigger job.

New versus used is often a legitimate question when buying camping equipment or RVs.   So-called "pre-owned" (used) items are less expensive to purchase than new ones, but sometimes repair or maintenance costs may favor buying new, especially if you're not a Do-It-Yourselfer.  If you decide to go with used items, be sure you are aware of any necessary repairs they may need before you buy.  Also consider whether you have the resources (parts, materials, skills, tools, time) to affect the repairs or the financial resources to hire someone else to do it.  Used tents, camping stoves, lanterns, and even sleeping bags are often a good bargain.  Some people have concerns about using personal items like sleeping bags but a trip to the dry cleaners should take care of that.  Check tents to be sure all the parts are there and that there are no major rips or tears.  Look out for leaking fuel tanks on stoves and gas lanterns.  They are not easy to repair and can be costly to replace.  You can usually save a LOT of money on used RVs, but shop around to get the best value.  Keep in mind the best value does not always mean the lowest price.  Consider age, mileage, condition, features, and how you plan to use the RV.  Buying a huge luxury motorhome won't be of much use if you plan to mostly visit Forest Service campgrounds that often have size limitations.  And  cute little Class B won't hold more than a couple of people (surprisingly, a lot of large luxury RVs are designed for only two people too).  Are you going to use your RV for a base camp for other outdoor activities?  If so, consider whether the CVWR (Combined Vehicle Weight Rating) is sufficient to accommodate your toys (boats, OHVs, etc).

You will encounter trade offs in choosing gear and equipment to support your camping and related activities.  Cost versus features will often be a factor.  Size and weight versus durability and convenience is also a frequent issue.  Availability of replacement parts may feature in consideration of vintage RVs and equipment.

There are many trade offs to be considered for other activities to be paired with camping.  First, do you even want or need any additional activities?  Then do you prefer group activities with high social interactions or more private and primitive experiences?  Do you enjoy using motorized toys?  Do you already have friends with which you would like to share an activity they enjoy?  Your budget (both available time and money) may help you determine what activities are within your reach and whether you can pursue new or used equipment.

Let the trading begin!

Wednesday, October 8, 2014

RV Batteries

RV batteries are an essential part of making RVs convenient and comfortable.   On motorhomes there are two separate battery systems:  a starting battery, and deep cycle coach batteries.  The starting battery functions just like the battery in any other motor vehicle, providing power to start the engine and operate lights and other 12-volt vehicle features, like radios and power windows.  The battery is charged by an alternator driven by the engine.  Deep cycle coach batteries are used to supply power for lights, fans, furnaces, and some electronic devices in the RV.  There may be one or more 12-volt batteries or two or more 6-volt golf cart batteries .  12-volt batteries are connected in parallel to supply higher amperage.  6-volt batteries are connected in series to create 12 volts.  Golf cart batteries are usually stronger, more durable, and can be recharged more times than 12-volt deep cycle batteries.  The house batteries should also be charged by the vehicle alternator whenever the engine is running and the should be separated from the starting battery by a battery isolator.  A battery isolator allows the alternator to charge multiple banks of batteries by prevents them from drawing down each other so you don't drain your starting battery while running your RV lights.

Other batteries.  The main focus of this article are the large (and expensive) 12-volt batteries that power your RV systems.  In addition to the 12-volt systems for your engine and your coach there are often other battery powered devices in your RV.  Smoke detectors usually use a 9-volt battery.  Remote controls for TVs, power awnings, etc usually use AA or AAA batteries.  You may have battery powered lights in cabinets or closets.  You may have battery powered lanterns and flashlights.  You will need to test the batteries in these devices regularly, especially before each trip, to be sure they will be functional when you need them.  For convenience, keep a battery tester in your RV or camp kit.  Carry spare batteries with you for all your devices.

Batteries are a critical component of the 12-volt electrical system that powers most RV lights and fixtures.  Not only do they provide power for the lights, but they also power control boards for furnaces, refrigerators, and hot water heaters.  Most modern furnaces also have a 12-volt fan.  Some older furnaces worked by convection only.  A convection furnace doesn't have a fan but it doesn't distribute the heat as well as a forced air model.  An anomaly of 12-volt furnaces is that when the batteries get low, the fan keeps running after the burner has shut off.  If you wake up in the middle of the night and your furnace is busily blowing cold air, your batteries may be low or you might be out of propane.  If that happens occasionally, (and you're not out of propane) you probably aren't charging your batteries enough during the day.  If it happens frequently, you probably need new batteries or a larger battery bank -- or don't run the furnace so much.

Pretty much all of these batteries are some form of lead-acid batteries.  Lead acid automotive batteries have been around since Cadillac introduced the first electric starters way back in 1912.  The basic design has not changed much in over a hundred years, but there have been some improvements.  Basic batteries use lead plates submerged in a solution containing sulfuric acid and are known as "flooded cell" batteries.   They have removable caps so you can check and replenish the water level as needed.  So-called "maintenance free" batteries are sealed and don't require the frequent addition of water in normal use.  Absorbed Gas Mat (AGM) batteries use saturated mats between the cells instead of liquid, reducing the chance of spillage.   Another option are gel cell batteries, in which the electrolyte, instead of being liquid sulfuric acid is a gel.  Gel cells are usually lighter than other batteries and very unlikely to spill.  By the way, it is best to only add distilled water when batteries need more liquid, but, in an emergency, ordinary tap water can be used.  The damage caused by contaminates in the tap water will be less than allowing the plates to be exposed.  Distilled water isn't very expensive.  It would be a good idea to carry a gallon jug of distilled water in your RV to top off your batteries as needed.  You can buy it at just about any grocery store for a dollar or so a gallon.

As the push for hybrid vehicles drives battery technology, new types of batteries are coming on the market.  Some are much lighter than lead-acid batteries and deliver longer life and much better performance, but as of now they are significantly more expensive.  Direct replacement deep cycle lithium ion 12 bolt batteries are currently nearly $700 each, making them about 4 times the cost of a pair of 6-bolt golf cart batteries.  Their longer life might make them pay off in the long run but they are certainly a lot more expensive up front.  I high performance, 80 amp lithium ion battery is over $1000 and will give 3,000-5,000 charging cycles.  I've even seen 300 amp batteries but they're big and heavy and expensive :  about $3500 each!  Lithium ion batteries allow you to use close to 100% of the capacitiy before needing to be recharged.  Lead-acid batteries only deliver about 50% of capacity before the voltage drops below workable levels.

If your lead-acid batteries need water frequently, they are probably being overcharged or charged at too high a voltage.  I once had the charging circuit in a converter go bad and found it was blasting the batteries with 18+ volts, which boiled out the electrolyte every few days!  Normal charging is usually about 13.5 volts and shouldn't exceed about 14.4 volts.  When the electrolyte gets low it allows the plates to become coated and clogged with sulfate, seriously reducing performance, capacity, and battery life.  I have read that you can treat lightly sulfated plates by adding distilled water saturated with magnesium sulfate (epsom salts) which supposedly disolves the deposits.  Add about 2 tablespoons of epsom salts to 8 oz of warm water and let it disolve completely before adding it to your battery.  Don't over fill the battery.  If the cells are really low (plates are showing), add about 1/4 cup of the solution per cell, then top it off with distilled water.  I have tried this with really badly damaged batteries without much success.  It may work better if applied sooner.

Many RVs, (motorhome, trailers, and campers) have a single 12-volt deep cycle battery to provide power for all coach needs.  If you do a lot of boondocking you may find a single battery doesn't have enough reserve capacity to meet your needs.  When that happens you may be able to find a location where you can install a second battery.  Replacing a single 12-volt deep cycle battery with a pair of matching 12-volt batteries in parallel will just about double your reserve capacity.  Replacing a single 12-vole deep cycle battery with a pair of 6-volt golf cart batteries in series will usually result in greater reserve capacity and longer battery life.  When installing 6-volt batteries they must be connected in series in order to produce 12 volts to run RV fixtures.  6-volt golf cart batteries are usually larger so you may have to enlarge the battery tray or find extra room someplace else if you want to convert to golf cart batteries. Make sure all connections between batteries are heavy gauge battery cables and that the 6-volt batteries are wired in series to create 12 volts. 6 volt golf cart batteries are usually larger than most 12 volt deep cycle batteries so you may have to modify the battery box and/or hold downs to accommodate them.  Motorhomes will have a separate automotive starting battery.  This should not be a deep cycle battery but in an emergency you may be able to borrow one of your coach batteries to replace a dead starting battery or use it to jump start your engine.  Some motorhomes have a switch on the dashboard that activates relays to connect the coach batteries with the starting batteries when you need extra starting power, precluding the need for jumper cables.  If you install extra batteries it is best to install it as close to the existing battery as possible and run heavy gauge battery cables between the batteries.  Batteries give off volatile gases (hydrogen) when they are being charged so they must be installed in a well ventilated space and should NOT be installed within the living area of an RV.  Suitable locations include outside cabinets and in the engine compartment.

There is a growing trend to large battery banks and inverters in large luxury rigs in order to handle a demand for quiet, portable 120-volt power anywhere.  An inverter is a device that changes 12-volt DC power into 120-volt AC power.    This is convenient for running entertainment systems and microwave ovens.  Some large luxury motorhomes even have large enough battery banks to run residential style 120-volt refrigerators full time, but that takes a lot of batteries and frequent recharging.  Keeping the batteries charged becomes a primary concern.  They can be charged from shore power, an on board generator, or from solar panels.  Solar systems can be expensive but once they are installed you get free power from the sun.  Some RVs have inverters built it.  If yours does not, they can usually be added (if you have sufficient battery reserves).  For small 120-volt devices you can often use a fairly inexpensive inverter that plugs into a cigarette lighter style 12-volt outlet.  Large inverters, say 1500-2000 watts, need to be hardwired with large gauge wire and the output can be routed directly to dedicated outlets.  Some RVs have an option to switch selected outlets from shore/generator power to inverter for added convenience.  But unless you know for sure you have plenty of reserve battery power, running 120-volt appliances on the inverter can draw you batteries down rather quickly.  120-volt appliances will consume power at 10 times the rate of 12-volt appliances of the same watts rating.  It is unlikely that units not designed for large battery banks will have anyplace they can be installed because they batteries take up a lot of room and add a lot of weight.  If you plan to install a large battery bank be sure the compartment floor is adequately supported to support the weight and that it is properly ventilated.  Never install lead acid batteries near any kind of device that may provide a source of ignition for the off-gassing that occurs during charging.

Proper maintenance is essential for good performance and long life for all batteries.  Some components of proper maintenance include avoiding excessive discharge, correct charging, maintaining tight, clean connections, and maintaining proper electrolyte levels as necessary.  Try not to let your batteries be drawn down until they are "dead" before recharging them, then use the right charging system to restore them to full charge as soon as possible.  Frequently check all battery connections to make sure they are tight and are not becoming corroded.  The terminals that connect the large battery cables to the battery posts are especially susceptible to corrosion and when they get corroded should be removed and cleaned.   The electrolyte levels in all but maintenance free batteries should be checked frequently and kept at about 1/2" above the plates.  A battery filler comes in handy for topping off your batteries.  You can buy them at auto  parts stores.  Always try to use distilled water to fill batteries so you don't introduce mineral or chemical contaminants that often occur in normal tap water.  However, if you're boondocking when you discover your batteries are low using ordinary tap water would be better than leaving them low.  Filtered water would be preferable to unfiltered water.  You want it to be as contaminant-free as possible.

One sure sign that your battery capacity is insufficient, is when the furnace fan continues to run after the burner has shut off.   That can also happen if you run out or propane, so be sure to check both battery and propane gauges before deciding what to do.  You may wake up cold in the middle of the night and find the furnace blowing cold air.  It is ironic that when the batteries get too low, the circuitry that shuts off the fan fails and the fan continues to run, further depleting the batteries.  If this happens with an old battery it may just mean it is time to replace it.  But if it happens with fairly new batteries or happens often, you probably need to increase your reserve capacity by installing a larger battery, multiple batteries, or converting to 6-volt golf cart batteries.  Of course, make sure you have been keeping your batteries properly charged before running off and blowing a lot of money on new batteries.  If you try to run your furnace for several days and nights without charging your batteries, you can pretty much count on it blowing cold air sooner or later.  If you don't run your generator enough each day or your solar system doesn't get enough exposure (shade or clouds for instance), your batteries are going to suffer.  You can check the state of charge using a voltmeter if your RV doesn't have a battery meter.   A fully charged 12-volt battery should normally read about 12.7 volts.  Be sure to test it without any charging voltage.  Charging voltage is often around 14.2 volts; "float" or maintenance charge should be about 13.8 volts.  Higher voltages will overheat the battery.  I once had a charger board in a converter that went bad and was putting out 18 volts.  It "fried" batteries like crazy!  I had to add water to my coach batteries a couple of times a week until I found out what was causing the electrolyte to boil away.

Here is a table of voltages and what they mean:

     12.7 = fully charged
     12.5 = 85% charged
     12.4 = 65%
     12.3 = 50%
     12.2 = 35%
     12.1 = drained

Battery indicators on the monitor panel don't usually give actual volts, but are calibrated to reflect approximate percentages, usually indicating 1/4, 1/2, 3/4, and full.  Checking the actual voltage at the batteries will give you a more accurate reading.  For best performance and longer battery life, avoid letting batteries get below 50% charge before recharging.  Note that even "dead" batteries should still show about 12 volts.  While that isn't enough to run lights, motors, or appliances, it may be enough to make a big enough spark or heating 0000 steel wool for lighting a fire.

Charging your batteries.   The alternator on motorhomes is usually wired to both the starting and coach batteries so it charges them all whenever the engine is running.  It should be connected through a battery isolator that prevents drawing down the starting battery while using lights and appliances in the coach.  A charging circuit can be wired from the alternator through the trailer connector to charge trailer batteries.  If your vehicle and/or trailer doesn't have this circuit it can usually be added at a nominal cost.  Be sure to include a battery isolator so using power in your trailer in camp doesn't run down your starting battery and leave you stranded.  There are two types of battery isolators:  solenoids and diode-based models.  Soleniods are usually less expensive and may have a shorter lifespan than diode models.  In either case they allow current to flow to charge both battery banks but keep a draw on the coach battery from running down the starting battery.  There is often much discussion among RVers about whether charging batteries with the vehicle alternator or the on board generator is better.  If you need a quick charge, using the vehicle alternator is probably your best bet and the engine at idle will most likely not consume much more fuel than the generator.  In camp, coach batteries are usually charged by the the converter whenever you run the generator.   If you use the generator enough, like to run the A/C for several hours on hot days, it will usually be enough, but in cooler weather you may have to schedule some generator time just to keep your batteries charged.   But be aware that the battery charging capabilities of most converters is limited.  Newer "smart" multi-stage converters like Progressive Dynamics "Intelli-power",  have more efficient battery charging systems.  Multi-stage chargers usually sense the battery condition and select one of four modes as necessary to maintain batteries in optimal condition.  The four modes are and their functions are:

     Boost Mode - (14.4 volts) to rapidly bring the battery up to 90% of full Charge.
     Normal Mode - (13.6 volts) to safely complete or maintain the charge.
     Storage Mode
- (13.2 volts) to maintain charge with minimal gassing or water loss during                                    periods of  non-use.
     Desulfation Mode - (13.2 volts with 15 minute 14.4 volt burst every 21 hours)

Compare that with the charging circuits on older converters that typically supply a constant voltage of 13.6 volts.  Some may sense when the battery is fully charged and reduce the amperage to maintain a "trickle charge".  The different voltages are required to provide proper charging and maintenance.  Boost mode helps recharge batteries quickly; Normal Mode tops off  and maintains the charge; Storage mode provides a "trickle charge" to compensate for normal voltage drop of batteries that are not in use; Desulfation mode provides a high boost during storage to "burn off" sulfation of the lead plates to maintain electro-chemical efficiency.

An easy and fairly inexpensive alternative to smart converters is to install an automatic automotive battery charger connected to the coach batteries and plugged in so that it charges them whenever there is 120-volt power -- from shore power or from the generator.  When using an external battery charger it is best to disconnect or disable the charger in the converter.  Another way to "quick charge" your RV batteries is to run the vehicle engine.  Estimates show it will use only slightly more gas than running the generator since the alternator is far more efficient at charging the batteries than converters and auxiliary battery chargers.  Of course, solar panels are also a good way to keep your batteries charged -- if you have a large enough array and sufficient sunlight.  You can buy little inexpensive panels that are plug into your cigarette lighter socket and are intended to be placed on the dashboard to provide a small "trickle charge" for helping keep batteries charged in storage.  These will not recharge batteries enough when they are being used when off grid.  Large solar panels are mounted on the RV roof and require a controller to provide proper voltage.  Of course solar panels work best in direct sunlight, so don't expect them to quick charge your batteries if you're parked in the shade.

Maintenance chargers can be used to maintain batteries while in storage.   Often referred to as "trickle chargers" because of the low (1-2 amp) charging current, they are pretty good for keeping batteries charged but not for recharging depleted batteries. If you have a good multi-stage charger connected to your house batteries, you shouldn't need a maintenance charger there, but you may still need one to maintain your starting battery.  The default charging voltage from the converter will usually override charging from automatic or maintenance converters so you may have to disable the converter in order to get the most from your chargers.  Those little solar battery charges that plug into the cigarette lighter are "trickle chargers".  By the way, make sure the lighter is live when the key is off or they won't do anything!

Batteries in storage will lose about 1% of their charge per month, even if they are disconnected.  Because of the parasitic draw of some RV appliances and accessories,  they be be drawn down a lot faster if not disconnected.  Some RVs come with battery disconnects.  They can be fairly easily and inexpensively added if necessary.  If you don't have a battery tender connected to maintain your batteries while your RV is in storage it is a good idea to disconnect them to avoid any parasitic draw down.


Saturday, October 4, 2014

Finding Water in the Wilderness

Water is one of the basic human needs.  You won't last long without it.  In a survival situation your first priority will probably be shelter .  You can survive only about 3 hours in adverse weather conditions before you succumb to exposure.  In hot times, you need to seek shade.  In colder or wetter times, you'll need shelter to conserve body heat.  Generally you can live about 3 days without water, although some people have survived longer than that and in high temperatures and low humidty or lots of physical activity or if you are one of those people who perspire a lot you won't survive as long.  Thus, finding water will be near the top of the list if you are in a moderate climate that doesn't require immediate shelter or after you've taken care of your shelter needs.

In forest and mountain areas you may be able to find natural sources of water:  springs, streams, ponds, lakes, snow and ice.  However, even water that looks clean is often contaminated with biological or toxic substances that could kill you faster than dehydration.  It is best to boil water from natural sources before drinking it or using it to cleanse wounds.  There is some argument about how long you need to boil it to kill germs, but the general thinking now is that you only need to bring it to a boil.  Note:  boiling does NOT remove toxins!  If the water is contaminated with toxic chemicals, like arsenic near old mining and smelting sites, it would still be dangerous after drinking.  In fact, boiling may concentrate chemicals as water is converted to steam.  Removal of toxins might require special filters or chemicals that would neutralize the bad stuff, neither of which you're likely to be carrying  around with you in a survival situation.  Some filtered water bottles are capable of removing at least some toxins.  Mountain tops often retain patches of snow or ice long into the summer months and these can be a possible source of water.  Clean snow is usually pretty safe but it may still be contaminated.  To be absolutely sure it is biologically pure, melt the snow and boil the water and let it cool before drinking it.  One way of getting really pure water is to capture steam from boiling water and condense it back to liquid.  You can get small amounts by soaking up the steam in a bandanna, letting it cool enough to condense the steam, then squeezing out the water for drinking.  For larger quantities you will need some kind of still where you can boil water and capture and condense the steam.  An easy way to turn small amounts of contaminate water or even urine into fresh water is via a solar still.  Dig a small hole in the ground and place a cup or other container in the center of the hole.  Pour the water you need to purify around the cup.  Cover the hole with plastic, securing the edges tightly with stones, dirt or other heavy objects.  Place small rock or other object in the center of the plastic directly over the cup so it pulls the plastic down in the middle.  As solar heat evaporates the water in the hole it will condense on the inside of the plastic, run down towards the rock in the  center, and rip into the cup.

Rain and snow are usually thought be "pure" and, usually, they are safe for a drinking water source.   However, if you consider that rain drops first begin to form around dust particles in the air you can see that even fresh rain contains some contaminants.  Rain from areas with high air pollution can be even worse, even to the point of becoming "acid rain".  In a wilderness survival situation it is likely using rain or snow to stay hydrated will be pretty safe, unless the rain tastes really bad -- or the snow is yellow.  Yellow snow in nature probably won't be lemon or beer flavored!

In dryer environments, like deserts, finding water is much more difficult.   On rare occasions you might find a spring or a stream.   Even if the stream appears dry there might still be some water in the ground, especially under rocks or overhanging banks.  The most likely place to find residual water is along the outside bank of curves in the stream.  To find possible stream beds in the desert look for patches or strips of green vegetation or watch animals and insects that might lead you to their sources of water.. You might get water from desert plants like cactus and prickly pear.  The juice from these plants may not be very palatable, but it might give you enough moisture to extend your survival time.  Don't use it if the liquid is milky or smells bad or tastes bitter as that usually indicates it is poisonous.  Even if it isn't poisonous, you may loose more of your precious body fluids by throwing up than you gain from trying drink nasty tasting stuff.  Prickly pear is a safe source of both water and nutrition.   Even vegetation that appears dry will  have some moisture in it if it is still alive.  Sometimes you can extract water from plants using a kind of solar still.  Wrap a section of the growing plant in plastic, sealing it as well as you can.  The heat from the sun should evaporate water from the plant.  When the plastic cools (usually at night), the moisture inside the plastic will condense on the inside surface and you can collect a small amount of water for drinking or medical uses.  Water collected in this manner does not have to be boiled.  You can also use a solar still (as described above)  to reclaim your own urine and extract drinkable water from vehicle coolant (most radiator fluid is 50% water).  Dig a small hole and place a cup in the bottom.  Soak the area around the cup with urine or radiator fluid.  Cover the pit with plastic and place a small stone in the middle so it forms a dent in the plastic directly over the cup.  As solar heat evaporates the liquid in the pit, it will condense on the plastic and drip into the cup.  Blood from animals you get for food might also be put into the pit.  Since most animal blood, including human, is quite salty, it is unlikely you'll get any hydration benefits from drinking the blood directly, but the water that evaporates from it in the pit would be usable.  A downside of putting blood into the pit is that it may attract varmints or may introduce a nasty smell as it decomposes.  Despite how dry things may seem, there may be some moisture in the air that will condense into dew at night.  Look to soak up dew from the leaves of plants or turn over a rock so the moisture can condense on the cooler underside.  Soak up the dew with a handkerchief  or other article of clothing and wring it out into a container or directly into your mouth.

Drink up!