Most efficient cells available?

[ckhorne]

I've seen a number of places where you can buy "typical" cells that reach 16% or maybe 18% efficiency. And I've read about research where they've reached much higher numbers - 25, 30, or even 45%. I realize that these extremes are in the lab, under ideal conditions, and with concentrators.

With that being said - what's the highest efficiency cells that a regular Joe can buy? I'm looking for 80-120w worth, so I'm willing to pay a good bit more for the efficiency. I just don't know what to google for to find them...

[Sunking]

With that being said - what's the highest efficiency cells that a regular Joe can buy?

19% but they will cost a lot. The 20 to 43% will cost up around $100/w and higher. Those are for military and NASA

Why is efficiency important to you? Does not mean anything unless space is an issue. The higher the efficiency, the higher the cost because they are MONO panels which have more silicon in them.

[Naptown]

19% but they will cost a lot. The 20 to 43% will cost up around $100/w and higher. Those are for military and NASA

Why is efficiency important to you? Does not mean anything unless space is an issue. The higher the efficiency, the higher the cost because they are MONO panels which have more silicon in them.

Well actually the silicon content is the same or extremely close, it is the way they are made either a block that is cut into wafers (poly) or pultruded into a single crystal and then cut into wafers (mono)
There are some that are pultruded into wafers directly.

[ckhorne]

Why is efficiency important to you? Does not mean anything unless space is an issue. The higher the efficiency, the higher the cost because they are MONO panels which have more silicon in them.

Space and weight are high priorities - I'm dabbling with a solar-powered UAV. While I can design and build the wings to be large and stable and the fuselage to reduce weight and wind resistance, I'd like for it to be mostly self-sufficient on power once airborne. I know others have done similar stuff - I just want a new project.

I'm willing to spend a little extra (even double and maybe triple) for 19-20%. I'm not willing to spend $100/w.

Like any good problem, the solution will be a careful balance between weight, size, power draw, efficiency, etc, etc, and because of this, I don't know what my power draw even is yet. Some experimentation with total available surface area for PV within the wings will lead to determining how big of a motor I can use, how much reserve battery I need, etc. Based on my back-of-envelope sketches, I can stuff around 70 watts on a 2meter wing using standard mono cells. I'd like to know if I can do do better. Different sized cells will lead to different design parameters for everything else (I can make a wing/fuselage of any size, but PV cells are fixed sizes...).

Any pointers as to where to find these higher efficiency cells?

[Naptown]

If you are credible and the operative word there is If you may want to contact Sunpower regarding purchasing some cells. They are currently in the 22-23% range.

[russ]

Contact Boeing and ask for their assistance - probably won't work but it is worth a try.

Have a good reason why you are special.

[SunEagle]

There was a guy from Switzerland that built a 3 meter glider similar to a radian where he used PV cells to keep his battery charged for long duration flights. What helped was that the plane was really a glider and only needed to power out of a low elevation since the receiver was a very low amp draw.

It looked like he had something but due to the crazy weather he had minimal time slots to test his RC plane.

If you are going to just fly then your power consumption can be kept to a minimum. If you are going for FPV then all those additional electronics and camera will be a major increase in load.

I wish you luck. If you are ever on the RCGroups.com website you will find me there as Eagle202.

[ckhorne]

If you are credible and the operative word there is If

Contact Boeing ... Have a good reason why you are special.

I'm starting to gather that it won't be worth my time to try. A few percent would be nice, but not uber-critical, so I'll just see what I can find with the mono silicon cells that are readily available...

[russ]

I'm starting to gather that it won't be worth my time to try. A few percent would be nice, but not uber-critical, so I'll just see what I can find with the mono silicon cells that are readily available...

Boeing cells are 40% as I remember

[ckhorne]

If you are going to just fly then your power consumption can be kept to a minimum. If you are going for FPV then all those additional electronics and camera will be a major increase in load.

I saw his posts the other day - it's a great reference point with real world data.

My initial plan was to use a traditional sailplane, but since I enjoy building, I thought I might be able to do a little better custom-designing. I'm currently thinking about a 2-3m wing with dual (or triple) carbon spars, so that I can mount the cells 1 or 2 rows wide down the length of the wing, and then covering the wing with clear monocote. The fuse will need to be tear-dropped shape and a T. Essentially a powered sailplane, as you said.

My plan is to actually make it semi-autonomous. I do iPhone programming, and I'm thinking about using a stripped down iphone for everything - it's got communications, gps, compass, I/O, and even a camera. If I can get the plane's weight down enough and use just the iPhone guts for the electronics, then I might be able to make it self-sustaining.

I wish you luck. If you are ever on the RCGroups.com website you will find me there as Eagle202.

I'm a long time reader, but never created an account. I may if this project gets off the ground...

[SunEagle]

I saw his posts the other day - it's a great reference point with real world data.

My initial plan was to use a traditional sailplane, but since I enjoy building, I thought I might be able to do a little better custom-designing. I'm currently thinking about a 2-3m wing with dual (or triple) carbon spars, so that I can mount the cells 1 or 2 rows wide down the length of the wing, and then covering the wing with clear monocote. The fuse will need to be tear-dropped shape and a T. Essentially a powered sailplane, as you said.

My plan is to actually make it semi-autonomous. I do iPhone programming, and I'm thinking about using a stripped down iphone for everything - it's got communications, gps, compass, I/O, and even a camera. If I can get the plane's weight down enough and use just the iPhone guts for the electronics, then I might be able to make it self-sustaining.



I'm a long time reader, but never created an account. I may if this project gets off the ground...

Sounds like a nice strong design. Love to see the finished product.

A friend of mine has been using an Autopilot board called ArduPilot. It can be found at a website called DIY Drones. It has the ability to be programed to fly the plane to multiple way points and then return to home without any manual intervention. He launches and lands it using a standard RC 7 channel radio but the rest is automatic. Pretty cool stuff.

[FloridaSun]

Boeing cells are 40% as I remember

Spectrolab is the division of Boeing that sells the cells tho there may be difficulty in a low volume purchase.

http://www.spectrolab.com/

[Sunking]

Afraid Mr Physics is going to kick your butt. The really high efficient panels are mono silicon. That may not mean much to you now, but it will because silicon is HEAVY.

The proof of concept solar planes use Thin Film technology which is basically thing plastic sheets that has PV sensitive material printed on the plastic sheets. Those super thin plastic sheets make up the skin of the aircraft. Very similar to shrink fit film used on RC planes. The advantage is obvious, it is super light weight.

Of the two proof of concept planes I know of one uses a hybrid gasoline/generator engine/motor to get it airborne, then once altitude is reached th eengine is shut down and the solar film then supplies power to cruise and descend. The other one uses a battery to take off and reach altitude, then switched to solar when the battery capacity is depleted.