This topic really deserves a posting of it's own, it is so diverse, and new options come out everyday.
Also, a factor that MUST be factored into the equation is water availability, as well as numbers intending to use the shower.
You can start out with the simplest form, the humble solar shower, black plastic bag left in the sun.
These usually are sufficient for ONE person per bag and iregular trips. One warning though with them, be careful how long you leave them in the sun, they do get incredibly HOT !
The second serves groups and relies on a fire, this is a 20 litre metal drum,(some come galvanised) with a system of piping within that allows seperation of hot and incoming cold water.
The idea with these units is tofill with cold water and place alongside your fire to heat up, when hot water is required, you simply place a METAL (recommended) bucket underneath the outlet and pour in COLD water into the inlet.
The incoming cold water pushes the hot to the top of the container and out the outlet. This water then can be used for any purpose incuding showering. Dilute it to desired temp, drop in your 12 volt pump and shower away. This sytem is very good for large groups and ensure hot water available at all times as long as there's a fire going.
The third option, is to purchase a purpose built hot water on demand system. The majority of these are powered by a 12 volt source and use LPG for the heating element, though there is a diesel powered version available at great cost.
The easiest and most popular would be the COLEMAN, though IMHO the hot water from this would not be hot enough for drinks as theyadvertise.
There is a similar unit manufactured by PRIMUS that works similarly.
Then lastly, there is the option of manufacturing or modifying a unit used for homes to your purpose of camping. These units can be purchased quiet cheaply on Ebay and with a little ingenuity and modification, make excellent camping units for anything from a small group to unlimited numbers with hot water available simply by turning on the tap.
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