I would like to show you my simple voltage level that I use in my system.

I used a resistor 1 kOhm,  green LED and Zener diode 10 V. Wiring diagram below:
As you see, the main principle based on Zener diode, which stays off until Zener voltage does not across its Zener voltage. In fact, in this case you need to add also an activating voltage of LED diode ( about 2 V for green colour). So ultimately you get minimum voltage level about 12 V to start LED lightening. Resistor 1 kOhm was taken experimentally. You can try with higher value, but I would not suggest to go down much lower than 1 k, as if above 12 V in installation the current value can make your diodes warm.

So, finally you install your indicator on one of your 12 V battery ( capacity does not matter) and from now on you are always aware if the level on your battery is above or below secure level.

BTW, I am going to test also red LED. As it requires lower voltage to light ( 1.6 V) it is possible to build up about 11.5 V indicator, having the same Zener diode.


    About me

    Hi, I am Michal. My idea was to start my own small scale PV system in my flat. I live in Poland, Warsaw district.


    February 2015
    December 2014


    Renewable Energy