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AC and DC power to light a Bulb

Former Member

Hello all!  I am trying a small project and I want to use a small solar cell (say 10vdc 500ma for roundish numbers) to supplement lighting up a 60 watt incandescent bulb.  Knowing that wall electricity is AC and solar cells put off DC I don't know how or if the bulb would use the power from the DC cell.  Also I don't want to have the AC power fry the solar cell, so I need to stop AC flow in that direction and I don't want the DC power to go back to the "grid" I want it to go to the light source.  Any thoughts on doing this?  Would I be able to get a lower net energy use if I checked it with a electricy usage devise like a kill-a-watt energy usage measuring devise or would the bulb just still draw the 60 watts and perhaps glow a bit brighter because of the slightly extra DC power? 

 

Would this be any different with a CFL or a LED bulb?

 

I'm not a electronics engineer...just a guy who tinkers so please excuse any major flubs!  Also I KNOW it's not feasable...I really want to make it work though...its fun to me!  Thanks guys! -Ron

Parents

  • 500 mA at 10V is 5 Watts.  So, don't expect to run a 60 Watt lightbulb.  I'll go with a presumption that you want to make enough light to read a schoolbook after sunset.  Please let me know if your end use requirement is anything different.

     

    You could charge up eight 1600mAh NiCad batteries with direct connection to this solar cell, though it might be a little safer to have various electronics in to regulate it.  Ignore that for now and get a pile of small batteries on your windowsill fully charged up.  Don't forget to disconnect them when the voltage goes over ten volts or they might blow up from being overcharged.

     

    9 to 10 V worth of batteries is about enough to power three "white LED's" in series (actually blue LED's capped with flourescent yellow) at 3.1 to 3.4 V each.  The 'large' ones are capable of 700 mA so on metal backplates of more than a square inch would tolerate direct connection to your solar photovoltaic. I'd expect battery power to be more useful for nighttime.  Three whites might tolerate direct connection to eight batteries, but DON'T do that without heatsinking them first.  It would be safer to have a 4 Ohm power resistance in series, which can be made from fine steel fence wire nailed to a brick or purchased.  The heatsink bases of LED's tend to be connected to one side of the semiconductor, so you'd need three metal plates for heatsinks and screw them to a brick or something which won't melt.

     

    This sounds rough because it is intended to be copied to Africa and places which cannot go buying heavy duty high quality parts for everyone; a car battery and inverter for example (which this solar cell is too small for).  The solar cell, batteries, and LED lighting are worth having, and everything else is more questionable.

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  • 500 mA at 10V is 5 Watts.  So, don't expect to run a 60 Watt lightbulb.  I'll go with a presumption that you want to make enough light to read a schoolbook after sunset.  Please let me know if your end use requirement is anything different.

     

    You could charge up eight 1600mAh NiCad batteries with direct connection to this solar cell, though it might be a little safer to have various electronics in to regulate it.  Ignore that for now and get a pile of small batteries on your windowsill fully charged up.  Don't forget to disconnect them when the voltage goes over ten volts or they might blow up from being overcharged.

     

    9 to 10 V worth of batteries is about enough to power three "white LED's" in series (actually blue LED's capped with flourescent yellow) at 3.1 to 3.4 V each.  The 'large' ones are capable of 700 mA so on metal backplates of more than a square inch would tolerate direct connection to your solar photovoltaic. I'd expect battery power to be more useful for nighttime.  Three whites might tolerate direct connection to eight batteries, but DON'T do that without heatsinking them first.  It would be safer to have a 4 Ohm power resistance in series, which can be made from fine steel fence wire nailed to a brick or purchased.  The heatsink bases of LED's tend to be connected to one side of the semiconductor, so you'd need three metal plates for heatsinks and screw them to a brick or something which won't melt.

     

    This sounds rough because it is intended to be copied to Africa and places which cannot go buying heavy duty high quality parts for everyone; a car battery and inverter for example (which this solar cell is too small for).  The solar cell, batteries, and LED lighting are worth having, and everything else is more questionable.

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