Hey, I’m new to arduino and I want to connect a solar panel to my breadboard, so I can power my project.My questions is, can I connect the solar panel and the lithium battery with a solar panel charge module direct to the breadboard?
For example this is the circuit I’ve made:
No. The Lipo doesn’t have enough voltage output nor regulation to run an Arduino. You need a boost regulator such as the rio rand lm2596 in core parts (putting “rio rand lm2596” in the part search box and pressing enter will bring it up.) then connect the battery (currently connected to the breadboard) to the lm2596 input, adjust the output to about 7V and feed that in to Vin on the Arduino. From Vin an internal regulator on the arduino will produce the needed 5V and 3.3V outputs. It is possible with care to power the arduino from the 5V pin but Vin is probably safer. Note as well your charger board doesn’t have battery protection, so unless your 18650 has an internal protection circuit it is possible to over discharge and damage the 18650. I expect the Reo rand will operate at a low enough voltage to damage an 18650 cell by over discharging it.
edit: another consideration is battery life. An arduino takes a couple of hundred milliamps to opertate (which will be more with the addition of the boost regulator) so a 2amp hour battery will only power the circuit for an hour or so (to check that, time it running on battery til the battery voltage gets to low, I think 3.7V or so is the usual lower limit ). If you need more battery life than that you would need to pick a lower power cpu board or you can also fix that by using a larger amp hour 18650, or several in parallel (although they need load balancing/charging boards which are available.)
Thanks a lot, I don’t need it to run so many hours, is a project for college and I’m trying to learn more about electronics.(If it runs 2 hours I’m really happy with it.Maybe in the future I would consider connect more batteries.)
One more question I’ve got, so I can connect the solar charge module to the rio rand lm2596 and then to the vin of the arduino?
Yes this looks correct. As noted you need to adjust the Reo rand to output about 7V (Vin will take between 6 and 12V as I recall.) You need to connect the charger to the Reo rand without the arduino being connected then adjust the pot on the Reo rand until the output voltage is 7V and you should be good to go.
Thanks, one more question I have if you don’t mind.
If I want to add up more batteries so the battery lasts longer, I need to connect another charger module so that I can add another 18650 battery?
Would it work like that?
No. The batteries need to be in parallel to add capacity, but 2 chargers will conflict with each other. You need a board that is designed to safely parallel 18650 cells (they can explode if overloaded so care is required.) I haven’t done it, but there are boards around that can do so while charging and protecting the cells.
I get what you are saying.
Would it work if I add up a 12v module charger(allows me to stack up batteries) with a 12v solar panel and then use Reo rand to reduce the output to 7v for the arduino ?
I hope my question make sense.