The water analogy is a classic, and works great as the form of the underlying physics is the same.
However, I think it is best to think of the water as charge, the voltage as height, and the electrical current as the flow of the water.
If you have water at 12 ft high, in some container, and you release a valve opening a tube full of air, it will flow through the tube to a lower height. This means the water loses some energy (via gravity), and if you want you can insert a paddle wheel that the flowing water will turn as it goes down. The wheel can be connected to a fan that keeps you cool.
So if you want, imagine your camp with a big tank of water raised up 12ft high. When you open the valve, the water has a pathway through the air to a lower reservoir at 0 ft, and you can use this energy to run your fan and stay cool.
The battery can be thought of as a bucket of charge at 12 volts. Charge does not flow easily through air, but it does through metal. You can connect a wire with a fan, and charge can now flow "down" from the positive terminal at 12 volts to the negative terminal at 0 volts.
If you want to refill your water tank at 12 ft high, you need to pour in water from a greater height, say 15 ft. So you need to expend energy to pump the water back up (or have a bucket brigade up a ladder) which is ultimately going to cost you a little more energy at least then you got out from the fan.
If you want to refill your battery, you must connect it to a greater voltage source, typically 14V, and charge will flow back into the battery.
Now there are a few important differences between flowing charge and flowing water. If I am pouring water out of a 12' high reservoir at a rate of 1 oz/sec, as I might a glass of wine, then I am releasing energy at a rate of about 1 Watt.
If I connect an aluminum wire the thickness of a paper clip across the terminals of a typical car battery, then this wire is thick enough to allow several hundred amps of current to flow through it - as much as the battery can supply. The rate of energy release can be more than 1000 Watts.
What happens to this energy? It turns into heat, hopefully just melting the wire, but also potentially causing serious burns.
So a very thin piece of wire can be enough to let an incredible amount of charge flow to lower voltage. Actual electronics have components that restrict charge flow to a reasonable rate and harness some amount of the energy, trying to minimize the amount wasted as heat.
Battery charging can cause outgassing. Basically, as you recharge hydrogen gas can be created, especially when the battery is near full. So it is important to regulate how quickly and at what voltage you charge the battery. In the analogy, one could compare this to splashing when you refill your water reservoir. If you pour in the water from too high or too fast, you will cause water to splash out, especially when the water is full. Luckily, there are inexpensive circuits that can regulate battery charging for you.
The battery is also like a slightly leaky reservoir of water. Over time it will lose charge, even if not used. So typically with a lead-acid battery one will keep it connected to a "float" charger which will keep a very small trickle of charge going into the battery.
The other difference between the water reservoir and the battery is that you can totally empty the reservoir and it is fine. With a typical deep-cycle battery, you should not empty it to much below 50% capacity or you risk shortening the lifespan of the battery. If you drop it to 0% and leave it there it may go completely dead.