Thin flexible solar panels

[Eric Greenwell]

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.


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Eric Greenwell
Richland, WA (USA)

[Vaughn]

"Eric Greenwell" > wrote in message
.. .
>
> 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.

Vaughn

[Paul Remde]

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

"Eric Greenwell" > wrote in message
.. .
> 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.
>
>
> --
> !Replace DECIMAL.POINT in my e-mail address with just a . to reply
> directly
>
> Eric Greenwell
> Richland, WA (USA)

[G.A. Seguin]

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,
Gilles










"Vaughn" > wrote in message >...
> "Eric Greenwell" > wrote in message
> .. .
> >
> > 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.
>
> Vaughn

[Nyal Williams]

At 15:12 12 November 2003, G.A. Seguin wrote:
>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 wrote in message news:...
>> 'Eric Greenwell' wrote in message
>> .. .
>> >
>> > 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.
>>
>> Vaughn
>

Howzabout some particulars?

[Eric Greenwell]

In article <GGosb.241760$0v4.17089702@bgtnsc04-
news.ops.worldnet.att.net>, says...
>
> "Eric Greenwell" > wrote in message
> .. .

> 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.


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.

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Eric Greenwell
Richland, WA (USA)

[G.A. Seguin]

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.
Gilles










Nyal Williams > wrote in message >...
> At 15:12 12 November 2003, G.A. Seguin wrote:
> >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 wrote in message news:...
> >> 'Eric Greenwell' wrote in message
> >> .. .
> >> >
> >> > 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.
> >>
> >> Vaughn
> >
>
> Howzabout some particulars?

[Rudy Allemann]

Eric Greenwell > wrote in message >...
> 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
>
Also available at Jameco.com are Powerfilm 15.4V /100mA units that
are 10x5.9x.02" for $45.

[David Kinsell]

"Paul Remde" > wrote in message news:QEpsb.182087$e01.657569@attbi_s02...
> 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.

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.


> But it does sound nice and worth investigating. Let us know how it works
> for you.
>
> Paul Remde
>
> "Eric Greenwell" > wrote in message
> .. .
> > 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.

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.

Dave


> >
> > 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.
> >
> >
> > --
> > !Replace DECIMAL.POINT in my e-mail address with just a . to reply
> > directly
> >
> > Eric Greenwell
> > Richland, WA (USA)
>
>

[Keith W]

>
> 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.
>
> Dave
>
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.

Keith

[Eric Greenwell]

David Kinsell wrote:

> 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.

These panels are rated at the "maximum power" point; the short circuit
current is higher, of course. In any case, the average will be as you
point out.

>>>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.
>
>
> A full panel these days (with an active transponder) easily draws over 2 amps.

My panel is not so full, apparently, with a radio, 302 vario/recorder,
Aero 1530 PDA, Becker transponder, as it draws about 650 ma while flying
(radio on, but not receiving or transmitting; transponder on mode C).
This will go up next year if I switch to an Ipaq PDA.

> The current you'll actually get out of the solar panel would not make a
> significant difference.

The $/ma was good enough, that trying a 200 ma set would give me a good
idea of their value, and more could be easily added. The engine doors
would hold over an amp's worth.

> You'd be more likely to notice the additional drag
> due to the turbulence than you would notice a benefit in the electricals.

At 0.008" thick (slightly thicker than wing tape), and placed on the
engine doors, I wouldn't expect any extra drag.

> If 36 AH of batteries (with a generator on your engine) isn't enough, you've
> got other problems.

It's enough for probably 3 typical flights (5-6 hours) with new
batteries. The generator doesn't charge at a very high rate, and for the
typical 6-8 minute launch, does little more than replace the starting
draw. I would go longer if a charge was needed, but it's much more
pleasant with the engine off!

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Eric Greenwell
Washington State
USA

[Eric Greenwell]

Keith W wrote:
> 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'.

I don't think it is significant, but these particular panels don't have
any specifications that would let you know. The Strobl panels the German
factories supply on their gliders seem to have the similar ratings when
used under a canopy.

> 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.

These panels are attractive in part because they are very thin (0.008
inches), about the same as wing tape. I"d put them on the engine doors
where the boundary layer is quite thick, but even behind the canopy
might be in a thick enough layer. The further back from the canopy, the
less drag.

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Eric Greenwell
Washington State
USA