Welding cables onto Wattson PCB to read Color Codes

It was not trivial because of the tiny dots I had to weld the wires to and because of the risk of damaging the PCB / components on the other side by overheating the area, but I managed to do it : Welding tiny cables onto Wattson PCB to be able to read the voltage of each color LED

Before, heating up the soldering iron

I easily put some solder on the 3 dots diagonaly placed on the board (left) and on tested soldering the ground wire (right)

Done, and I was releaved that Wattson still displays everything correctly after that step

It's easier with a good LED light to see the fine details

Now testing color mode: it works too

and I can read voltages :-) (blue & red LED here)

With green now (switched on sevral Grid Tie Inverters for that)

I had to drill a little hole in the back panel of Wattson to fit the cable

I am using a old USB mouse cable, that provides a standard plug with 5 contacts and I need 4 here (ground, blue, green, red), so I put a red label onto the USB cable next to the plug warning that this is not a normal USB plug and should NOT be plugged into a computer for example (that would be bad...)

Reading voltages of blue and red LEDs

The USB plug plugged into a USB outlet and voltmeters leads attached to screw terminals

Voltages are going up and down, because Wattson "glows", it is not a solid color, butI realized that colors are more or less intense dpending on the energy level of the usage and the generation, so I can read the corresponding voltages and deduct what is going on ...

Water heater is on, all red now (very intense = 4.53V here) and blue is 0V