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Can any electronics be run off a 12W flexible panel?
By rgagnon, Section Solar Posted on Sat Feb 23rd, 2008 at 06:20:50 PM MST
Flexible solar panel - uses?

I've bought a 12W 12V 800mA flexible solar panel mostly as a bit of an experiment.
I was a bit disappointed that it couldn't run a 600 mA 4.5V CD player directly off a cigarette lighter adapter (CLA). What would be a more realistic power output from this panel? 800mA is it's maximum output.
Should an overcast day reduce the power output from the panel so drastically that it doesn't even light up the indicator on the CLA?
Are there any thoughts about what kind of electronics devices could run directly off the panel? I also bought a Xantrex 200+ powerpack to store energy from the panel. It would still be fun to be able to run a player or fan off the panel because of the panel's nice portability. A 20lb battery isn't very portable.

Can any electronics be run off a 12W flexible panel? | 16 comments (16 topical, 0 editorial)

Re: Can any electronics be run off a 12W flexible (3.00 / 0) (#1)
by AbyssUnderground on Sat Feb 23rd, 2008 at 12:43:20 PM MST
(User Info) http://www.repowered.co.uk

Ideally you can't run anything directly from a panel but you can store it in a battery. For a 12W panel, a 7-17Ah SLA battery would be ideal as storage, which you can then hook things up to. This is roughly how I started off.

Take a look at www.repowered.co.uk and the 6W Home made panel page (last link on the navigation). Maybe this will help you out.

http://www.repowered.co.uk - My Renewable Energy site.
msn[at]m3ezw.co.uk - my msn if you want a chat.

Re: Can any electronics be run off a 12W flexible (3.00 / 0) (#8)
by rgagnon on Sat Feb 23rd, 2008 at 11:57:24 PM MST
(User Info) http://solardiary.com/

Interesting site!

I'll spend more time on it over the next few days. It does sound as if you took a similar route to the one I'm trying.

[ Parent ]

Re: Can any electronics be run off a 12W flexible (3.00 / 0) (#14)
by rgagnon on Tue Feb 26th, 2008 at 02:04:35 PM MST
(User Info) http://solardiary.com/

http://www.globalsolar.com/index.php?option=com_docman&task=doc_view&gid=104

The instruction sheet for the 12W (or whatever it really is) flexible panel says: "When in use, the Folding Solar Power Panel will adjust its voltage and charge the electronic device at its intended rate." The 25W version doesn't say that and provides a warning about its usage to direclty power a 12V device.

I'm not sure how much stock to take in that.

[ Parent ]

12W flexible panel? (3.00 / 0) (#2)
by jonas302 on Sat Feb 23rd, 2008 at 01:15:58 PM MST
(User Info)

maybe charge some AAs for the cd player it will take a while with a small panel like that

not much (3.00 / 0) (#3)
by mettleramiel on Sat Feb 23rd, 2008 at 04:34:22 PM MST
(User Info)

You will be lucky to get 400ma from that panel. I have 45watts of thin film, so theoreticaly, I should get about 3 amps. I have never seen more that 1.5 even on the brightest of days. Thin film panels are absolute garbage. I too was fooled by their initial low cost. Learn from this and save up for a crystaline panel.

Yes, an overcast day will drasticaly reduce your output. You might get 1/4 of your normal current even when the clouds are barely covering the sun and it stills apears fairly bright out.

As far as running things directly off of the panel, you could run a computer fan off of the smallest of panels. I've also ran my cell phone directly off of a 5 watt panel a few times. I'm willing to bet that an mp3 player would work pretty good, especialy if it has no screen. Remember, just because something says it only uses 600ma, doesn't mean that it won't use more at start-up or any other time for that matter.

Re: not much (3.00 / 0) (#4)
by ghurd on Sat Feb 23rd, 2008 at 07:01:23 PM MST
(User Info)

mettleramiel,
OT: If you have not seen more than 2A, I expect something else is not correct.
Don't get me wrong, I am THE guy who bad-mouths thin film, but something else has to be very wrong.
Maybe start a new post, with the specs, distances, wire gauges, controller, everything.
There is no reason you shouldn't see 2.5A easy, at noon, on a good day.

Rgagnon,
Think of panels as providing amps. A bit of haze will make the amps fall like a rock.

Please be careful with connecting a panel direct to a device.
Most of the time, the device takes much less than the sticker says.
A 3.6V 100ma device can easily be blown up if connected directly to a solar panel.
Trust me. I have blown up a lot of stuff.

The best idea is to charge a 12V battery and use the battery to operate the device.
G-

[ Parent ]

Re: not much (3.00 / 0) (#5)
by mettleramiel on Sat Feb 23rd, 2008 at 07:07:34 PM MST
(User Info)

No, everything is fine with them, the thing is, 2 of the panels are 2 years old and the third is more(bought it used). I used to get just under 2 amps with the first 2 panels when they were new, but as thin film tends to do, they deteriorated. The third panel never put out more than about 0.7amps.

[ Parent ]

Re: not much (3.00 / 0) (#6)
by ghurd on Sat Feb 23rd, 2008 at 07:30:48 PM MST
(User Info)

Open the PV J-Box, check the screw connections.
NTL had a lot of trouble with them too.
G-

[ Parent ]

Re: not much (3.00 / 0) (#12)
by AbyssUnderground on Sun Feb 24th, 2008 at 10:56:28 AM MST
(User Info) http://www.repowered.co.uk

I have 2x18w thin film panels and the most I've ever seen is 1.7A, and that was rare, very rare. I usually see no more than half that.

http://www.repowered.co.uk - My Renewable Energy site.
msn[at]m3ezw.co.uk - my msn if you want a chat.
[ Parent ]

Re: disappointing (3.00 / 0) (#7)
by rgagnon on Sat Feb 23rd, 2008 at 11:45:58 PM MST
(User Info) http://solardiary.com/

That's disappointing to hear. That's not too surprising in a fashion.

I mostly got the flexible panel for its portability and wasn't figuring that it would be as good as a rigid one. The one I got folds up to 9"x6"x0.7". If nothing else, I suppose that it should at least be good for charging small batteries. How sturdy are rigid panels for travel?

I'm not sure if I'll be buying any larger panels. The sad thing I've found as I look more and more into photovoltaic power is that it remains very cost prohibitive and most people will not likely ever see a return on investment. It's one of the reasons why I'm more focused on portable uses.

Does the Cigarette Lighter Adapter provide any protection to devices hooked up to it? Are there any batteries that can be charged and used at the same time? The instructions on the powerpack said that should not be done.

I'll be keeping a log at http://solardiary.com/

[ Parent ]

Re: disappointing (3.00 / 0) (#9)
by Flux on Sun Feb 24th, 2008 at 01:58:33 AM MST
(User Info)

Yes PV is expensive. Direct powering of devices is tricky, most devices are voltage operated and panels are current sources. If you don't use any battery as a buffer you need electronic converters to match the panel voltage ( varies with sun but typically 16v) to the load voltage ( I think you said 4.5v)

At best it is only going to work in full sun, the panel volts hold up fairly well in shade but the current falls rapidly.

Big panels, small loads and full sun, otherwise it is a no go area.

At present thin film panels and the amorphous ones are not reliable technology, they may get better.

Wind up radio may be better than direct solar.

Flux

[ Parent ]

Re: disappointing (3.00 / 0) (#10)
by finnsawyer on Sun Feb 24th, 2008 at 09:02:41 AM MST
(User Info)

Expensive, you say. It was recently reported that one of the school districts here in the U. P. of Michigan was trying to raise $100,000 to put in a 10 MW PV system. That doesn't sound expensive at all. Maybe you just haven't found the right source, or maybe the system will really be 10 KW. Chuckle.
GeoM
[ Parent ]

Re: Can any electronics be run off a 12W flexible (3.00 / 0) (#11)
by wooferhound (tim((NoSpamAt))wooferhound.com) on Sun Feb 24th, 2008 at 09:53:54 AM MST
(User Info) http://wooferhound.com

Quote
"I've bought a 12W 12V 800mA flexible solar panel mostly as a bit of an experiment"

They are not 12 watt panels. 12v at 800ma is 9.5 watts.
W o o f -={(

Re: Can any electronics be run off a 12W flexible (3.00 / 0) (#13)
by fungus (info@reenergy.co.uk) on Sun Feb 24th, 2008 at 11:40:38 AM MST
(User Info) http://www.reenergy.co.uk/

I easily see 2A from my two 18w panels on a clear summer day so ..

'Two things are infinite: the universe and human stupidity; and I'm not sure about the universe.'-Albert Einstein
Fungus - www.reenergy.co.uk

Re: Can any electronics be run off a 12W flexible (3.00 / 0) (#15)
by greenene (info@greenenergiesllc.com) on Wed Feb 27th, 2008 at 07:17:49 PM MST
(User Info) www.greenenergiesllc.com

A 4.5 volts dc appliance can very well run on a6volt panel by simply using three AA rechargeable batteries. Think about it., 3 batteries and a 6 volt panel will probably cost you less than a 15 W panel.

Since every dc device will have a battery compartment, all you need is to find a way to connect the panel in parallel with the batteries.

As to the power needed.... if your device uses an average of 600 ma per hour, a typical 250 ma 6 volt will happily charge the batteries without the risk of overcharging them. for every hours you run the device, you will need slightly more than two hours of sun.

The rule of thumb of charging batteries without a "controller" is 1/10 the battery capacity.
So if a battery is rated at 2300 ma, it should not be charge a rate greater than 230 ma per hour. These are general rules, but they keep you from accidentally overcharging and destroying batteries.

Hope this helps.

tony cervone
green energies, llc
greenene

Re: Can any electronics be run off a 12W flexible (3.00 / 0) (#16)
by rgagnon on Thu Feb 28th, 2008 at 06:50:30 PM MST
(User Info) http://solardiary.com/

I quickly tried the panel with my Maha battery charger, set for a slow charge (which uses 300ma), and it lights up showing a charge on the batteries. It appears that this will work. The charger is supposed to have smart circuitry that should charge batteries at an appropriate rate.

This is an experiment for me and it will hopefully show me results that will encourage me to buy bigger panels that will accomplish more.

[ Parent ]

Can any electronics be run off a 12W flexible panel? | 16 comments (16 topical, 0 editorial)

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