These cool little doovalackies check the voltage output of your car’s battery quickly and easily

Simply plug this handy voltmeter into the cigarette lighter socket and get an instant readout of the electrical systems voltage.
Great for a quick reading to know it’s time to recharge.

Whilst they are not as accurate as some of the more complex battery monitors however they do give you some indication what’s going on down there.

So what do the numbers mean?

 The temperature number at the top displays the temperature of the area where the reader is plugged in.  

The voltmeter number indicated how much battery charge is left in that particular battery.  You can check the percentage levels below on this little battery monitor chart I made.  I have stuck mine inside the fuse and switch cubpoard next to where the monitor is plugged in for a quick visual reference how the batteries are going.

Download the battery monitor chart for yourself here, print it out.  Cut it to size and stick it somewhere near your monitor so you can work out percentages quickly.