Welcome to a new InTheMail the series that will touch both your passion for electronics and your bank account at the same time. People seem to like this starting line so I’ll keep using it, it’s the truth anyway so why not.
Here is a list with links to all the items shown in this video:
Do I recommend getting this module? Yes, the accuracy is good, the resolution is nice 10mV 1mA and you also have the option for adjusting it manually for both voltage and current.
The design is pretty simple, I believe the microcontroller is an STM8S so hacking it and rewriting the firmware should be pretty easy but it already does what it’s supposed to do so I don’t see a point to hacking this module. I think you would be better off designing a panel meter from scratch.
Someone asked on youtube how should a panel like this be wired up, so here is a wiring diagram that you can use. In this wiring diagram our goal is to monitor the voltage and current for charging a battery.
Example 1 shows the panel meter connected before the battery charging module, which means it will measure everything, even the power losses in the battery charging module.
Example 2 shows the panel meter connected after the battery charging module, which means it will only measure current flowing into the battery or whatever load you have on the output.
In both cases voltage sensing is done right at the output but that wire can be moved according to your needs. Also in both cases the panel meter gets power directly from the power supply because at that point the voltage is constant.
The main thing to remember here is that these panel meters are designed for low side current sensing, that means the ground of the logic board of the meter is connected with the input of the shunt resistor.
You might remember this small module from the previous InTheMail, this is the Ruideng dc-dc converter with a claimed efficiency of 95%. Now a figure of 95% efficiency is not unheard of these days, many dc-dc converters can achieve this with proper circuit design.
This particular model uses the MP2307 converter chip manufactured by Monolithic Power and if we take a look at their datasheet we can immediately see where they got the 95% efficiency figure they advertise.
If you own fancy equipment like a source/measure unit than one instrument can do all the measurements and data log the results as well but a source/measure is out of our budget so we will be using multimeters for this test.
Here are links where you can find the equipment used in this video: