DL69-2048 Multi-functional Digital-Display Meter

[Hellnoh2o]

I just put in a D85-2042A digital volt/amp meter in my controller. So far it works well. I hooked the voltage side between the source and ssr controller as others here have recommended, and hooked the amp portion to the load side. Love the controll this thing has. Was a little disappointed that I couldn't monitor the load voltage but oh well I am still very pleased

[skow69]

That's the thing. According to Edwin's tests, it gives an accurate measure of power, in watts, going to the element, even though it reads volts on the line side. If you want the load side volts you can get it by dividing power by current (watts/amps) but since it gives power accurately who cares? I fought the idea until he proved it. And explained it.

[raketemensch]

So, 7 months later, how's it holding up?

[Edwin Croissant]

Out of curiosity I ordered a PZEM-004T module from China.

This module can measure RMS voltage, RMS current, active power and total energy usage over time and has a opto-coupled TTL serial connection to get the values remotely. Great if you want to interface it with an Arduino or something like that.
For less then 10 euro it's a bargain

Unfortunately the PCB design sucks In my opinion it is unsafe

The creepage distance between the opto-coupler and serial output pins and the mains is a miserable 0.25mm. As the module is rated for 260V this should be 2.2 mm minimum.
The resistor that is used as voltage divider for the chip is a 1 mega ohm MCR10 SMD resistor that is rated for 150V voltage drop maximum. As the peak voltage at 260V is ~370V this resistor should be replaced with preferable four 250 kilo ohm resistors in series.