How can I use a car battery safely for outdoor power supply?

Okay so I need to know how I can safely use a car battery outside. I want to use it as a power source for a water heater for my horse water. The water heater will be using about 12-30 watts. I want to make sure that the battery is also protected from weather such as rain. Is there any way I can do this? Or is there an other way I can supply power to the heater with out cords?How can I use a car battery safely for outdoor power supply?
30 watts at 12 volts requires an ampere draw of about 2.5. It may not sound like much but it will pull down a good battery in a few hours so two 6 volt deep cycle batteries (like a golf cart or a RV) hooked up in series to create 12 volts would be a better choice than a single 12 volt battery. Assuming no cords that leaves solar as a better choice than, say, wind. This requires solar panels that can produce at least 60 watts (assume 50/50 day/night) to keep the battery charged. If the heater is 115 volts then an inverter will be needed to convert the 12 volt DC to 115 AC. The panels charge the battery, the battery runs the inverter, and the inverter runs the heater. Some solar panels have voltage regulators and others do not. You will need one to control the voltage output of the solar panels so if it isn't included then a separate one will have to be purchased.How can I use a car battery safely for outdoor power supply?
Why do not you get a small generator it? ? Small power generators safer outdoors.

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