Hello, what friends today I bring you other tools that not only the mechanics need to have and is a small tester that tells us with the ignition of an LED if the alternator is charging the battery of our vehicle.
Many mechanics to check if the battery is charging or not what they do is disconnect a terminal of the same and if the car does not turn off is because the alternator is supplying the necessary energy to keep it turned on. The problem with this technique is that we operate the regulator inappropriately and it occurs on instantaneous voltage due to the load rejection that the alternator undergoes. Then it has to be absorbed by the entire electrical system of the vehicle.
In old cars there was not much problem with this, but with the new ones that own computers and many electronic systems this procedure is not very friendly. hehehe
So with the above, if you do not want to invest or do not have a multimeter on hand, it suits you to make this small tester, simple but effective that will let you know if the battery is charging.
- 2 Resistance of 680 Ohms per 1 / 4W (R1 and R3)
- 1 Resistance of 360 Ohms for 1 / 4W (R2)
- 1 12V 1 / 2W Zener Diode (Dz1)
- 1 Transistor 2N2222, NPN. (Q1)
- 1 Green Led Diode to show that it is charging. (LED 1)
- 1 Red Led Diode to show that it is on. (LED 2)
- Other materials to make welds and join the materials.
Diagram of the tester.
How does it work?
In theory, the principle that it uses is that when the alternator sends charge to the battery, the current circulation increases the voltage of the same much more than 12.5V. Of course this would not be fulfilled with a battery with deep discharge, but for that case it is not even possible to start the engine, then we would fall in the process of auxiliary with another battery and doing this because our device will work properly.
As I said before, if there is more than 12.5V then we have an alternator sending charge to the battery. To detect this, we use a 12V zener coupled to the base of the NPN transistor.
If you are fond of electronics, you will know that our Zener will start driving when the 12V is exceeded, but as you can see in the diagram, the base of our transistor is directly energized, so in addition to the 12V driving of the diode, it is also necessary overcome the voltage drop in the Base / Emitter semiconductor which adds about 0.5V of more approximately so by exceeding this threshold it will turn on our LED connected to the collector of the transistor. The resistance in series what makes the limit the base current of the transistor so that it is not destroyed.
As you can see it is quite simple to do and put into practice and as I mentioned at the beginning, this tool should have it all the world.
If you know electronics you can improve it and make it try many more things. ; )
Here is a video of how I did it
Well, I hope you like it and thank you very much for the support.
En este video realizo la prueba del sensor/suiche del retroceso del Chery Orinoco o A3. Por lo general esta es la falla más común cuando hay problemas con el encendido de las luces de retroceso y el sonar del carro.