MCIGICM Digital Voltage Tester, Mini DC Voltmeter 2.5V-30V with 0.28 inch LED Display (Pack of 5) Review

I asked "What current do they draw for each color?" In my final project I will be running from (2) 9v batteries in series, so 18v. I wanted to know which voltmeter draws the least current so my batteries will last the longest. The winner was (surprisingly!) White. Here are the numbers: Yellow 17.33mA @ 18V Red 14.09mA @ 18V Green 12.51mA @ 18V Blue 9.43mA @ 18V White 6.90mA @ 18V I thought that the white color with multiple (RGB) LEDs is obtained, because I thought that this draws more actual…

They are designed for a minimum voltage of 2.5 V (red) to 3.0 V (blue/white). Unfortunately, they don't work that low. The reds and yellows stop showing the correct voltage at around 3.6V each, and the blues don't even show anywhere between 4V and 5V. If you need to monitor voltages over 5V, they're great. Very bright and looks pretty accurate to within 0.1V. Anything else doesn't work though.

These things are great for casting where you need to control the tension. Two-wire ones aren't as accurate, but easy to hook up without a separate power supply. Mine were all a few tenths of a volt but easily matched to my voltmeter. The adjusting screw is VERY sensitive, so you will need to turn it a little to set it properly. For me 13.5 vs 13.6 doesn't matter. If you need higher accuracy, this is not for you.

I bought these for a project that used a dedicated battery board and they were perfect for voltage monitoring, to damage the multimeter unnecessarily. They are accurate enough for what I needed them for and given the price I would consider them a good deal. Several times my multimeter showed 3.7V and this one 3.8V or vice versa, but I can't tell for sure which one was off. It didn't matter either as I didn't need high accuracy and the readings were reliable despite the slight variance. If you…

[UPDATE] The manufacturer seems to have fixed the issues in this review. Solder joints are much more consistent and cleaner, all modules look the same (apart from the color) and packages now have a small colored marker to indicate which module is which. Useful. You'll still need to adjust them to the desired voltage range, although this should be easy with a small Phillips screwdriver. [Old Review] > Pros: Affordable, easy to use, bright, adjustable, great addition to a DIY project. A: I got