need advice for a secondhand solar panel that draws 18-19v without a load

5 Posts
Jun 3, 2009 04:40 pm
need advice for a secondhand solar panel that draws 18-19v without a load

Hello all.  I have a secondhand solar panel that draws 18-19v without a load.  I don't know the amperage, but can't imagine it'd be more than 4 or 5amps. 

Would this blow out a 12v regulator? Would I have to buy a 24v regulator even though it draws much less than 24v without a load? 

And if I get a 12/24v regulator that auto-detects which to use, could such a regulator output 12v to a 12v deep cycle battery?  Or would I have to get a 24v regulator and 24v battery? 

Thank you all! 
 
Jun 3, 2009 08:31 pm
Re: need advice for a secondhand solar panel that draws 18-19v without a load

Wow! No information at all about it? Name or serial number? What are its dimesions and how many cells does it have? What color and shape are the cells? Does it have an aluminium frame (painted or unpainted) and J-box with screw terminals inside?

While trying not to get into semantics, when I hear that an electrical device "draws," I think "a load draws an amperage of..." Were you write that it "draws 18-19v without a load." thats called open circuit voltage. If you take a look at the rating of new PV modules listed in Alt-E Store, you might see that certain 12 volt nominal, PV modules have similar open circuit voltages to yours. (Most likely not because of the age difference.) As well there is rated amperage and short circuit amperage listed as well as wattage. These are all measured¬ using a STC or Standard Test Contition. There is also "peak" voltage or what I call the "working voltage" of a PV module. This is listed as well. So there is; Open circuit voltage, peak or "working" voltage, and nominal voltage. The last one, nominal voltage is not "listed" but it may be advertised.
What you have sounds like a 12 volt nominal PV module with a working voltage of maybe a little better than 14 volts. Not a good panel for hot regions like the equator. For the sake of simplicity I won't go into PTC ratings chances are your PV module was made before all of that came along (see below.)

Again with the semantics. When I hear regulator, I think of the voltage regulator on a 57 Ford pick-up truck or something. Sorry. Look up charge controllers in the Alt-E Store.

Chances are that it may only make about 2 or 3 amps, There are certain handheld electric meters that can measure dc amperages in series.¬ 

http://www.sunlightelectric.com/pvmodules.php
« Last Edit: Jun 5, 2009 11:38 am by Thomas Allen Schmidt »
 
578 Posts
Jun 3, 2009 08:45 pm
Re: need advice for a secondhand solar panel that draws 18-19v without a load

hello,

get a $30 multimeter that can measure at least 50v dc and 10adc and you can figure out what it is.  if your voc is around 20, it is likely a 12v nominal module.

watch this video, tell us the results. 

http://videos.altestore.com/

(2nd one down)

if you dont go that route, with other info, we can play guess that module, and then help with the rest of the components for battery charging if that is what you are after.

guess that module is one of my favorite games!!

mr. schmidt is correct, any info helps in guess that module, including:

color, size, # of cells, size of cells, color of frame, color of backing material, does it have a junction box on the back, where is the j box, how big is the j box, does it have glass on the front or something else . . .

james
altE staff

AltE
"Making Renewable Do-able"
http://www.altEstore.com/

Tel: 877.878.4060 x107  or +1.978.562.5858 x107
Fax: 877.242.6718  or +1.978.562.5854
 
5 Posts
Jun 4, 2009 03:55 pm
Re: need advice for a secondhand solar panel that draws 18-19v without a load

Hey all, sorry for the lack of details before. ¬ I'm in a small port village in Ecuador, and this panel was part of an old sonar marine buoy salvaged from the local waters. ¬ 

And thank you for your input! So, I bought a multimeter and the panel has around 19v open circuit voltage. ¬ It seems to be mounted onto plastic. ¬ Screw terminals are on the back. ¬ The brand is Zunibal (www.zunibal.com). I called the company but everyone in the Spanish company seems to only speak Catalan, so I couldn't get the product specifics. ¬ 

However, I took some photos, it's just over a foot long, maybe a foot and a half. ¬ The last photo is the panel next to a size 10.5 men's running shoe. ¬ 

http://supervegan.com/blog/images/campaigns/500-IMG_1380.jpg

http://supervegan.com/blog/images/campaigns/500-IMG_1379.jpg

http://supervegan.com/blog/images/campaigns/500-IMG_1378.jpg

http://supervegan.com/blog/images/campaigns/500-IMG_1374.jpg

From your input, I'm guessing now I'd need a 12v charger and a 12v battery and 12v inverter? ¬ 
 
5 Posts
Jun 4, 2009 05:10 pm
Re: need advice for a secondhand solar panel that draws 18-19v without a load

Ah, so James, if I just want to use my solar panel to power my laptop or maybe a couple lights, would you recommend going with a 12v Pwm charge controller?  Would it also come with all the required cables to connect to the solar panel if the existing cables on the solar panel aren't long enough? 
 
578 Posts
Jun 4, 2009 07:20 pm
Re: need advice for a secondhand solar panel that draws 18-19v without a load

perfect!

i never would have guessed that one.¬  i would argue that foreign modules from buoys dont count for guess that module, but perhaps i am just a sore loser.

the first photo is all that i needed.¬  if you count all the little rectangles you will get 36.¬  36 cells in series = 12v nominal.

based on size that is likely between a 10 and 20 watt module when it was new.

that would mean that a relatively simple small controller should work fine for you.

here are some expamples.

http://store.altestore.com/Charge-Controllers/Solar-Charge-Controllers/Pwm-Type-Solar-Charge-Contollers/Morningstar-Charge-Controllers-Pwm/Morningstar-Sunguard-45A-12V-Pwm-Charge-Cntrlr/p793/

http://store.altestore.com/Charge-Controllers/Solar-Charge-Controllers/Pwm-Type-Solar-Charge-Contollers/Steca-Solar-Charge-ControllersPwm-Type/Steca-Solsum-6A-1224V-Charge-Controller/p1537/

http://store.altestore.com/Charge-Controllers/Solar-Charge-Controllers/Pwm-Type-Solar-Charge-Contollers/Morningstar-Charge-Controllers-Pwm/Morningstar-Sunsaver-Ss-6-6A-12V-Pwm-Charge-Cntrlr/p803/

http://store.altestore.com/Charge-Controllers/Solar-Charge-Controllers/Pwm-Shunt-Solar-Charge-Controllers/Specialty-Concepts-ASC-Charge-Controller/Specialty-Concepts-ASC-12V-4A-Solar-Charge-Controller/p1480/

good luck,

ask anything else if you need to.  - one other thing, when wiring a charge controller, always wire controller to battery first, then solar to controller.

james
altE staff

AltE
"Making Renewable Do-able"
http://www.altEstore.com/

Tel: 877.878.4060 x107  or +1.978.562.5858 x107
Fax: 877.242.6718  or +1.978.562.5854
« Last Edit: Jun 4, 2009 07:24 pm by James Cormican »
 
5 Posts
Jun 4, 2009 10:56 pm
Re: need advice for a secondhand solar panel that draws 18-19v without a load

Ah, thank you! 

One more question, since there's no Radio Shack here in this small Ecuadorian village (and one internet page takes a few minutes to load when it's strong enough to detect Google >.<).  Do you also have fitting 12v power inverters and the cables (to go from the solar panel to the regulator, and from the regulator to the inverter and battery)? 
 
578 Posts
Jun 5, 2009 11:43 am
Re: need advice for a secondhand solar panel that draws 18-19v without a load

from the module to the controller, 10awg (4mm^2) or 12awg wire should do fine.

the wires from the battery and inverter will depend on the size of the inverter. 

james
altE staff

AltE
"Making Renewable Do-able"
http://www.altEstore.com/

Tel: 877.878.4060 x107  or +1.978.562.5858 x107
Fax: 877.242.6718  or +1.978.562.5854
 
Jun 5, 2009 12:30 pm
Re: need advice for a secondhand solar panel that draws 18-19v without a load

Interesting. Nice find. I took a look at the Zunibal web site... Very secretive, they sure don't want to share too much information about their products. I only saw two items that have what appears to resemble, but not exactly, your PV module; the "FOR-TUNA" and, the "TUNABAL 15."
 It would appear though that these two devices are equipped with battery and therefore a charge controller of some sort. I guess all of that didn't come with? The battery can't be but so big. Sealed drycell maybe, light weight (has to float.) I would guess the charge controller is a simple one, all electronic obviously. Maybe a simple shunt or load diversion type.
Best of luck to you building your system Tod.

http://www.satamatics.com/pub/news/action=article/cpr=cpr0005/vcpr=1/Zunibal_Signs_up_for_Satamatics_Global_Coverage.htm

http://weblog.greenpeace.org/pacific/archives/001698.html
 
5 Posts
Jun 5, 2009 11:12 pm
Re: need advice for a secondhand solar panel that draws 18-19v without a load

Thank you all for your help! ¬ I decided to go with the Steca Solsum 6A 12/24V Charge Controller. ¬ Thomas, yeah there wasn't anything else usable we could get with the solar panel (eg the battery was completely dead and couldn't hold any more charge). ¬ I feel pretty fortunate that the solar panel still works. ¬ And a friend from the states is sending me this:

http://www.radioshack.com/product/index.jsp?productId=2194431

to use with the AltE charge controller so now all I gotta do is look for a soldering iron in this fishing town. Wink ¬ 
 

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