Hello everyone,
I am working on a project that involves measuring the voltage, current, and power of a 370W solar panel using Arduino. I want to find out how much power the panel produces in a day, depending on the solar irradiation. I've done some reading around this topic and have gotten myself a bit confused, so I'm looking for a bit of guidance to straighten me out.
According to the panel specification, the voltage and current at maximum power are 34.3 V and 10.79 A at standard test conditions. This means that I need a power resistor load with a resistance of about 3.17 ohm. My question is, how can I measure the voltage and current of the panel using a voltage and current sensor or a voltage divider using Arduino Mega? Do these sensors withstand that much power?
Measuring the power output of a solar panel is far from trivial, as it depends on illumination and panel orientation. So far, your goal is a bit too vaguely defined for people to advise in detail.
A couple of points:
The maximum power point of a solar panel depends on the illumination, so no one fixed load resistor is ideal.
The open circuit voltage produced by the panel is largely irrelevant for the measurement, as that does not depend strongly on illumination. The short circuit current, however, is directly proportional to the illumination.
To measure the current, you need current sensors capable of handling more than the panel could possibly produce. ACS712 (20A) is OK, or high side instrumentation amplifier sensors like the INA260.
As an aside, you won't learn anything less about the overall measurement process if you choose a much smaller panel, then you don't have to deal with relatively high voltages and currents.
Hi @jremington , thank you for your explanation. My goal is to find the relationship between solar irradiation and the output power of this particular solar panel at a particular location. So for the panel, I can't use a smaller one because my project is related to that panel. So, as you mentioned, the INA260 sensor, which I didn't know was this type of sensor available on the market. Do you think that sensor can do the work for me and stand that much power?
Solar panels, as already mentioned are not for beginners to play with.
Capacity is done with a tong meter with the panel on short circuit.
+1
The INA260 is just a sensor. Current only, because open panel voltage is too high for this sensor.
If you want to know the exact power generation of a panel, then you need a device that can absorb the full power of the panel, and continuously adjusts it's maximum power point. Because that power point fluctuates with illumination and panel temperature. I don't know if such a device exists.
As jremington said, it could be better to use a smaller panel, and from there guestimate what the large panel could produce.
What is the final application. Grid connection or battery charging.
Most MPPT chargers could have an LCD display, with harvest information.
Leo..
The purpose of this project is to investigate how the output power of a specific solar panel varies with solar irradiation. Therefore, I think it would be more appropriate to use another device that can record and store the data for further analysis instead of Arduino.
We understand that, but it's not that simple. A solar panel is not just a voltage or current source. To extract max power you must measure voltage and current to find optimal load voltage for that max power point, and absorb up to 400 watt at the same time.
The Arduino is the easy part. Building some sort of high-power variable zener diode is not.
Think 20 high-power transistors, and a heatsink the size of a shoe-box.
Leo..
What will you be using to measure the solar irradiation?
I'm going to use Renke pyranometer to measure the solar radiation
Hi, @kamronn13
Welcome to the forum.
Have you Googled;
finding mppt of a pv arduino
As this is what you are trying to do for different levels of solar radiation.
Tom... 
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