Hello, I am working on a project and I want to power an Arduino Uno using a 9V solar panel. I have researched how to connect everything, but I am worried about short circuits or damaging the components. Can someone please guide me on how to safely do this? These are the materials I have: Arduino Uno, 9V solar panel, MPPT solar charging module, TP4056 lithium battery charging module, LM2596S DC-DC buck converter, MT3608 DC-DC boost converter, and lithium-ion batteries. Thank you!
UNO operates on 5 volts, what is the purpose of the boost converter?
How much current does your various components require?
I know the Arduino Uno works on 5V, but I only have a 9V solar panel, so I will use a regulator to safely lower the voltage. The boost converter is to increase the voltage if it becomes too low from the battery or solar system. My parts (sensors, LCD, RGB LED, buzzer, joystick, ultrasonic sensor, water and soil sensors, and DFPlayer with speaker) need about 300 mA on average, and can go up to 500–600 mA when everything is working at the same time. I am still a beginner in electronics and not very knowledgeable yet.
This is a technically advanced project, not for beginners.
A solar panel can be used to charge a battery, which then powers the Arduino. However, the Uno is a very poor choice because it an old design that runs on 5V, and there are very few solar charger/battery combinations that will run it without technical modifications.
You will be much better off using modern Arduino compatible MCUs that run on 3.3V, along with about 95% of all sensors on the market. I recommend the Adafruit Feather series with a built in lithium battery connector and charger. You will still have to implement a "low battery" detection and shutdown protocol.
Before making any connections, please purchase a digital volt meter. Then you can make proper measurements and avoid damaging components!
I understand, and I was actually thinking about that, but I don’t have enough time left to order new parts. I’ve already finished most of my code and circuit design, so I want to work with what I already have and focus on powering the system safely. Thank you for replying.
How much POWER (volts times amps) can your PV panel supply?
Would a multimeter work?
Then this project is out of the question. You cannot do what you want with the parts you listed. The charger(s) you chose will not properly charge a battery that is under load.
Pick a different project that you can do with the time you have left.
A late start on a class project?
If I change the solar panel to a 5V one, would it work better for my setup? My project is not mainly focused on solar charging, so it’s okay if it doesn’t end up working, but I wanted to include it to make the system more sustainable since the topic is sustainability.
Here is what is written on the back of my solar panel:
Type: Polycrystalline silicon solar panel
Rated power: 9V 3W
Output wire length: 10 feet
Application range: 5V to 6V battery charging
Vmp (optimal operating voltage): 9V
Imp (optimal operating current): 330 mA
Voc (open circuit voltage): 10.8V
Isc(short circuit current): 383 mA
STC conditions: 1000 W/m² irradiance, 25°C cell temperature, AM 1.5 solar spectrum
Same as a digital multimeter. Analog or digital both measure voltages, current and resistance.
Thank you, I will try that.
9V at 330mA = ~3 watts. If your buck converter is 85% efficient at 5V, it's output would be about 500mA. Is that enough current for all your components (loads)?
Yes, I think so, but I’m not completely sure .I am using a DHT11 temperature and humidity sensor, a water sensor, a soil moisture sensor, and an ultrasonic sensor, along with an LCD screen, joystick, buzzer, RGB LED module, and DFPlayer with speaker. I have already finished their circuit. Do you want me to send the specs of the boost converter?
Here is the link for the one I have. https://share.temu.com/vcZrR2XXTkB
No, the only load I see that might give trouble is the LCD backlight and speaker, good luck.
Okay, thank you. Sorry, one more thing, do you think if I charge a battery and then use that battery to power the Arduino that way it will work? Thank you for helping me.
What kind of battery?
If you do your battery charging somewhere else, then a lithium battery could feed into the MT3608 boost converter to produce 5V, and that could connect to the 5V pin of the Uno, as well as power the other 5V stuff. But as I remember, you would have to be careful not to connect USB power at the same time.
I don't think you can safely use the TP4056 to charge the battery because charging might never terminate, and you don't want that. Also, the panel voltage is too high for the TP4056. But you also said you had an MTTP charger. Can you provide more info on that?