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Permalink Reply by Eddie Furey on July 14, 2012 at 11:45pm

I'm far from an electronics expert, but the general consensus from similar threads in the past has always been that carrying the weight of the solar cells uses more power than they generate.

Although this plane seems to have made it workable.

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Permalink Reply by Logan Nelson on July 15, 2012 at 12:39pm

Thanks Eddie. After doing a little more digging i discovered the same thing. The power output to weight ratio (if you wanna call it that) just isnt good enough for this application. Hopefully, something is developed in the future and becomes cheap enough that we could get a solar cell light enough to charge the battery while in flight to get some flight times in the hours with the same batteries we use now.

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Permalink Reply by Jake Stew on July 15, 2012 at 3:44pm

The power to weight doesn't really come into play.  The amount of power you can generate from even a relatively large solar panel is completely insignificant to the power required.

Solar would fail even if it was weightless.  You simply couldn't carry one large enough to produce any significant amount of power.

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Permalink Reply by Logan Nelson on July 15, 2012 at 4:50pm

@jake...I was talking about more of recharging the batteries with solar while they ran the aircraft....if only to increase flight times of battery powered flight by 15 or 20 minutes...I doubt there are any solar panels small enough to fit on an RC that would generate even enough power for the control system

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Permalink Reply by Jake Stew on July 15, 2012 at 5:24pm

What I'm telling you is that feeding maybe 500 milliamps of solar power into a 80+ amp system is of no practical use.

A 5'x5' solar panel puts out about 2.75 watts of power in full sun.  2.75 watts @ 12v = 0.229 amps.

Most quads use 20+ amps per motor.  20 x 4 = 80 amps.  So even if your solar panel weighed nothing and didn't totally screw up the aerodynamics and you had full sun... you would only be getting 0.2% back.  

Assuming you had a 30 min flight time that would give you an extra 3.6 seconds.  That's not counting the weight or the aerodynamic issues.

So my point is that even weightless aerodynamically perfect solar panels (which don't exist BTW) wouldn't be of any practical benefit.  So we can skip the hard calculations and just write them off right away.

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Permalink Reply by Logan Nelson on July 15, 2012 at 6:00pm

And yet again math disproves a theory :)...you are correct sir...thanks for your input

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Permalink Reply by Jake Stew on July 15, 2012 at 7:03pm

Solar might have a place with drones though.  You could build a solar power landing pad. The idea would be to have a solar power station charging batteries in the landing pad.  The drone would land and charge from the solar fueled batteries and then run it's missions.

It would be pretty slick to charge a drone in remote areas using a solar station.  You just can't practically carry the solar panels in the air.  But you could have a solar power drone with current tech.

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Permalink Reply by Logan Nelson on July 15, 2012 at 8:06pm

That would definitely be possibly if you used something like the charging pads they have for phones and the like now a days...it would really have to be stepped up in power(if you were going solar) to achieve anything like the current chargers we have now but I could see something like that....make a nice flat surface on the landing gear to touch down on the mat or something like that

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