I am currently doing a project on the solar panel, and I am at the last step, which is to measure the voltage and current of the solar panel so as to know the power to display it on my dashboard. However, I am with a problem.
So my voltage value was correct when I haven't connected it to the charge controller but however, when I connect it to the charge controller, it is measuring the wrong voltage value (which I suspect is from the 12V battery)
The solar charge controller has an output of 10A
The voltage before connecting to the charge controller that hooked up with the battery is correct depending on how much the sunlight is.
Voltage after connecting to the solar charge controller was "12.45V" consistently even without sunlight
I have attached the circuit diagram of my connection below:
Yes, there is something quite wrong with your circuit.
At night, when the sun is down and the solar cell is not receiving light, the solar cell WILL draw current from the battery. That will do 2 things, drain your battery quicker and damage the solar cell. Put a reverse current blocking diode between the positive lead of the solar cell and the PWM controller.
Next DO NOT measure the current from the solar cell, you want to measure the current between the battery and the load. Do not measure voltage across the solar cell, you want to measure voltage across the battery.
Think of your circuit containing 3 parts. Part A is all the components between the connection to the PWM controller and the solar cell. Part B is all the components between the PWM controller and the battery. Part C is the battery load section.
For part A you want current to flow from the solar cell to the PWM Charge Controller.
For part B current will flow to and from the battery to the charge controller.
For part C current is with the battery and the load.
Whiles part A and C are important, part B is the one that should be the most free to do its thing.
Your project does not run off the solar cells, you project runs off the battery.
My biggest suggestion is ditch the PWM Charge controller and get a MPPT charge controller. That LCD display burns through electricity at night when you are sleeping and not looking at the display. I got 4 of them sitting in a junk box.
Thanks for the speedy reply, however for my project, even tho it is powered up by the battery and the battery is charged by the solar panel, however, I need to know much voltage/current the solar panel is receiving from the sun.
A proper schematic would be more readable. Many people here won't even try to untangle pretty pictures, AKA Fritzing. All I see is a picture of some unidentified components connected to unidentified pins. I don't use a Mega so I am not going to look up the pinouts to see what your connections are since the labels in the picture are fuzzy white blobs. A proper schematic with labeled connections would be more readable.
You haven't said anything about the controller or what is the thing with the green connectors? You also didn't say what the "wrong voltage" is. What are you expecting and what are you getting? And to save us from having to look it up, what are the specs of the "voltage sensor"?
Why.
Charging current (or power) and load current (or power) is all you need to know.
Because that also includes controller efficiency.
Two INA260 modules could be used for that. They also measure battery voltage.
A 10A controller (we didn't see a weblink) and I assume a matching (large) solar panel,
so it should already have a blocking diode fitted in the connection box.
You can measure panel current with an ACS712, but it's irrelevant if you use an MPPT controler.
Battery/load current will be different from solar current.
You likely can't use the voltage module. Many controllers regulate the negative side of the panel, so the voltage divider always measures battery voltage.
Leo..
HI,
You need to check the solar controller, most switch the PV out of circuit using the NEGATIVE lead, NOT the POSITIVE that is usually assumed of the PV array.
This will cause your voltage readings to be inconsistent.
Check this first. without the voltage sensor connected.
Can I also suggest you get used to posting schematics rather than fritzy type cut and pasted images.
If... the controller regulates the negative wire of the panel (likely),
then you could measure panel voltage with five resistors.
Three to measure negative of the panel, which could swing between + and - 15volt.
And two to subtract positive panel voltage from negative panel voltage.
Cumbersome, and irrelevant information.
Leo..