On cars use electric fans for radiator cooling of the cooling system. The fan is an impeller on the DC motor installed in a round or square frame. The inclusion of the fully automatic electric fan depends on the coolant temperature in the radiator. Data on temperature of the liquid is removed from a sensor installed in the side compartment of the radiator. The sensor is a simple microswitch whose contacts are normally open. They closed upon reaching a certain temperature.
To connect an electric fan, you can use two schemes: relay and basileios. The difference between these schemes is evident from the title. Basileia circuit consists of temperature sensor, fan, fuse, connecting wires. Positive terminal of the blower motor is connected through a fuse to the positive terminal of the battery. Negative terminal of the fan can be connected to any output of the temperature sensor, the polarity of inclusion does not matter. The second terminal of the sensor must be connected to the car body. This is the easiest circuit that does not require much time to implement.
Relay circuit contains a Electromechanical relay. Good because high current is removed from the sensor to the relay. Positive terminal of the fan is connected through a fuse to battery, negative to the body. The negative wire need to be cut and the resulting two wires to connect normally open contacts of the relay. By default we have disabled the fan. One output of the relay must be powered from plus battery through a fuse or the ignition switch. The second terminal of the coil must be received by the first contact of the temperature sensor and from the second contact to mount the wire connected with the body. Advance look at the relay is a diode across the coil. If so, it is important to observe the polarity of the coil supply.
Another useful refinement to the scheme and the inclusion of fan is button, installed in the car. The temperature sensor may deny the most inopportune moment, so the emergency button will be useful. As the first circuit and using the second, you need to connect normally open contacts of button temperature sensor. It's easier, but in the case of using the first scheme will be that the button is large current and this can cause scorching of the contacts button and meltdown of the housing. Therefore, the best button to use in a duet with the solenoid.
Advice 2: How to connect two batteries
There are two ways to connect power sources: parallel and serial. The first increases the total voltage while the second container. An increase occurs in the number of times equal to the number of sources.
Make sure both batteries are the same, equally worn and not worn to the same degree. If not, their serial or parallel connection refuse.
To connect two batteries in series, connect the negative pole of the first of them with the positive of the second. Terminals, the remaining free (positive terminal first and negative second), among themselves do not connect in any case, otherwise there is a short circuit. They remove the stress, increased in two times.
To connect two batteries in parallel, take two diodes, able for an unlimited period to sustain the load current. The negative pole of the battery connect together. The positive pole of one battery connect to the anode of the first diode and the other anode of the second diode. The cathodes of diodes connect together. Connect the load negative terminal to a connection point of cons battery positive to the connection point of the cathodes of the diodes. This design will give the same current two times longer than a single battery. But loading it twice large current is impossible, because always open only one of the diodes.
To connect batteries in parallel without diodes are not recommended as they will be discharged through each other. Do so only with the full confidence that they are equally loaded and worn. But with this design you can remove two times more current.
Before to charge the battery, disassemble design. Charge them individually. This will dramatically reduce battery life. If the batteries are connected in parallel using diodes, charge them without dismantling the structure, moreover, is not impossible.
After charging is complete, assemble the design of the back and connect it to the load. Continue operation of the battery.