Thin flexible solar panels

I've come across some thin (0.008 inches), flexible solar panels that look like they'd be ideal for gliders. These are the PowerFilm 7.2V 100mA ($30) units, with and without adhesive on the back:
http://store.sundancesolar.com/pow72v100maf1.html

So, $120 would buy me 4 panels, which would give me 200 ma at 15+ volts, almost enough keep up with my panel (including the transponder) over a full day. By 'full day', I'm including the time it's tied out, as it would be at a soaring camp or on a safari, and a five hour flight.

Has anyone used these, or know anything about them? Are there any better units than these? I'm aware of the Strobl units from Germany, but they are about twice the cost per amp.

No, I don't know anything about those particular panels, I just want to point out that even with only 200 ma of charge, you will need a charge controller or you risk cooking your battery. Last time I checked, they were a $29.00 item. I ruined several batteries before I learned.

Hi,

I have heard that solar panels are rated a bit optimistically (like glider polars). So you may not get as much current as you think you will.

But it does sound nice and worth investigating. Let us know how it works for you.

Paul Remde

Hi, I have used flexible solar panel fot 14 seasons. Voltage never drop below 12 volts with one battery 12v 7 amps even after 6-7 hour with all electrics on. Specs are: Open circuit voltage 18V Short circuit current 200 m.a, charging 12v 160 m.a., 14v 140 m.a. Max power 3 watts and diode protected prevent flow-back. dept is <.5 inch ( today they are thinner) and 10X10 inches on top of my solar panel. Flex to 60 degrees max. I run a L-nav, garmin gps and Microair radio and logger.

Regards,

Howzabout some particulars?

Good general advice. I can get away without using one because I have a 36 AH battery in my motorglider, and the battery specs allow even higher currents for charging without a controller. 200 ma would be too much for the typical 7 AH battery, however.

Hi, I own this glider for 14 years. First battery lasted 11 years, present one 3 years old. To avoid overcharge turn radio on when you connect the battery or install a on/off switch. My battery is on charge full time when not in the glider. This advice was given to me by the technician who maintain the alarm system at work some 15 years ago. It works. At my club one other glider has the thin flexible panel on top of the motor door, never a problem. Regards.

Also available at Jameco.com are Powerfilm 15.4V /100mA units that are 10x5.9x.02' for $45.

Sometimes the current rating given is into a short circuit, so you get substantially less in practice. I'm sure these particular ratings are for the panel laid flat, pointing directly into the sun, with no cloud cover. Wrapped on a fuselage, frequently pointing away from the sun, the average will be a whole lot less.

A full panel these days (with an active transponder) easily draws over 2 amps. The current you'll actually get out of the solar panel would not make a significant difference. You'd be more likely to notice the additional drag due to the turbulence than you would notice a benefit in the electricals. If 36 AH of batteries (with a generator on your engine) isn't enough, you've got other problems.

Is that the generator attached to the spare bike pedals for something to do when the pilot gets bored? 8-)

But more seriously, would the material of the canopy absorb the frequencies used by the solar panel - if not, would there be a problem with mounting the panel inside the 'glass'. Even mounted outside, I suspect that the joint around the canopy would cause sufficient turbulent layer that the extra 'roughness' would not be noticeable, if the panel were to be mounted behind the canopy.