DC 0-199.9V 200V Blue LCD Digital Volt Panel Meter Voltmeter

This meter does work. However one thing that is very important about this meter. Unlike other panel meters, The meter supply voltage must be isolated from the measurement voltage. This means you can not connect the two together in any way. Another thing is that the meter supply voltage can be either AC or DC 12 volts. I suspect that this is the reason the two must be isolated. I write this since this is different then the most common digital panel meters. Which is neither good or bad, but just meant for a different purpose... In other words, if you need to have a common ground or want to measure the same voltage that supplies power to this meter. Then is is not the meter for you.

This item arrived on time but had no instructions other than what's printed on the item, you can see it in the picture. The I wanted to measure a 12V battery voltage to make sure it worked. Lon term I had planned to monitor a 48V supply so this was just a test. I connected "1" and "3" together and "2" and "4" together, and I assumed that 1/3 would be the power and 2/4 the ground. Well, I guess not, as it gave no display, but the blue backlight did turn on. I had also bought some Drok meters and they all worked great, so I am returning this one and buying a Drok meter with the voltage range I need.

Reads low, and some times not at all.