Hi there, I got like 47 solar cells with each one output 1v and 0.08A but I need a solar panel that can output 12V 2Amp to charge 3 x 18650 battery and power up my arduino. I don't want to waste my money on buying a new solar panel so I came up with this schematic. Is it okay to use this kind of method or it will burn off the electronics? thanks in advance
You have a 12V 18650 battery pack?
Outside of it being solar powered, which charger are you using?
I do believe your math is wrong, and hence you wiring. The capacity of solar cells is very similar to the capacity of batteries (similar, not same).
The schematic shows 24 pairs of 1V cells. Each pair would make 2V, the 24 pairs would produce 1.92A. So you have 2V at 1.92A. To get what you want the math is (best case)
2A /0.08A = 25 sets of cells
12V out / 1V cell =12 cells per set.
25*12=300 solar cells.
You are going to need a few more solar cells.
Damn, just realized that I need 12V 2A to output from battery not from solar cells :-X
So can you recommend me how much juice that I need from solar panel to charge the battery pack(3x18650 3.7V 3800mah) and arduino uno?
A TP4056 module charges one or two 18650 cells in parallel from 5V.
n1ckelov:
Damn, just realized that I need 12V 2A to output from battery not from solar cells :-X
The 3x 18650 will do that for a short time. But charging them in series as a battery pack is far more complicated than charging them in parallel. Then charging an series-parallel 18650 (or any Li-Ion pack) is even more complicated.
How long do you need 2A? 10 seconds, 10 minutes, 10 hours, 10 days?
maybe i should reduce to 2x18650 and use voltage booster? Im afraid that the solenoid valve 12v powered by the arduino wont work properly
maybe 30 minutes is sufficient?
I you want it to last for 4 hours, then you need to find a 12V 8Amp-Hr Hour battery. For homebrew, I think Li-Ion batteries are out. You in the realm of sealed lead acid or gel cell batteries.