Needing a little help, as I have been researching and reading up about electronics for this project, and ended up confused!
My project is to do away with my solar garden lights that break/need repaired every year, and make my own setup. I plan to bury 40 glass bricks i have acquired around the edge of my garden and put run a white led to the bottom of each. I have bought some leds, but struggling to work out the size of 12 vsolar panel and 12v deep cycle battery i need. The relevantled specs are as follows, not sure what reverse current is yet! This is the only data i could get on them :
Forward Voltage Typ Forward Voltage Min Reverse Current Vr=5V
If=20mA If=20mA Max
3.4 3.0 10
I took it that each leds draw is 20ma.
I put this into a calculator and it suggests 10 runs of 4 leds in series with a 1 ohm resistor in each run. The results were:
I am not sure if my draw per hour is 200ma as results above, or 40 x 20ma which is 800ma?
Now i am getting lost as to what specs battery i need and solar panel. I guess the 200ma or 800ma draw is per hour. So i am thinking then i need a battery with either 1.6 a capacity or 6.4 a minimum capacity for 8 hours of running.
For the panel I am trying to work out what i need by using P=VI so power is 12v x 0.2= 2.4W or 12v x0.8=9.6W. I think this means the Circuit will use either amount per hour. So for 8 hours of use i will need 19.2Wh or 76.8Wh. I think i can calculate the panel from that, but could someone please let me know which figure i should use or where I have gone wrong, thanks, allan
My project is to do away with my solar garden lights that break/need repaired every year, and make my own setup. I plan to bury 40 glass bricks i have acquired around the edge of my garden and put run a white led to the bottom of each. I have bought some leds, but struggling to work out the size of 12 vsolar panel and 12v deep cycle battery i need. The relevantled specs are as follows, not sure what reverse current is yet! This is the only data i could get on them :
Forward Voltage Typ Forward Voltage Min Reverse Current Vr=5V
If=20mA If=20mA Max
3.4 3.0 10
I took it that each leds draw is 20ma.
I put this into a calculator and it suggests 10 runs of 4 leds in series with a 1 ohm resistor in each run. The results were:
- total power dissipated by the array is 2404 mW
- the array draws current of 200 mA from the source
I am not sure if my draw per hour is 200ma as results above, or 40 x 20ma which is 800ma?
Now i am getting lost as to what specs battery i need and solar panel. I guess the 200ma or 800ma draw is per hour. So i am thinking then i need a battery with either 1.6 a capacity or 6.4 a minimum capacity for 8 hours of running.
For the panel I am trying to work out what i need by using P=VI so power is 12v x 0.2= 2.4W or 12v x0.8=9.6W. I think this means the Circuit will use either amount per hour. So for 8 hours of use i will need 19.2Wh or 76.8Wh. I think i can calculate the panel from that, but could someone please let me know which figure i should use or where I have gone wrong, thanks, allan