Quote Originally Posted by Clive S View Post
Not sure what you mean by "what switch" but these little meters are quite good for the price. Just connect the red and yellow wire to a + 12volt and the black to the -ve and it will read the voltage of the battery. If you want to read above about 30V then you have to connect the red wire to a source below 30V and the yellow wire to what you want to measure up to 100V. The -ve has to be to be the same for both the supply and the higher voltage you want to measure.
It would of course be prudent to put a fuse in line to protect the cables ..Clive
I wish to read either the battery voltage or the solar panel voltage separately, so i thought i would a switch of some sort