small PV solar

[David Haig]

hi Don.....   the panel I have with me is an ARCO 16-2000.    has 33 round solar cells.   I did a search on it and found an old HP (HomePower)  testing report:

 

The date of this test
was 12 January 1993.

See Home Power #23, page 20 for a complete rundown of our PV
module test jig and procedure.

We reported on their hot
weather performance in Home Power #24, page 26.

Carrizo ARCO 16-2000
This is a 9.5 year old ARCO 16-2000 module we purchased on
the open market. It has 33 series connected, single crystal,
round PV cells. We've had this module out in the sun for the last
1.5 years.

That makes this panel 24 years old.  checked my cd set and found the article, they reported that it tested (at 8 years old) to be  16.7 Volts   2.2 Amps  (using a shunt).

that's in cd #2  .... HomePower issue #24   page 26.

 

I set up today between 3:30 and 5:15 pm.....    measured 18.4 Volts at first then gradually dropped.  I saw down to 16.7,  but it seemed to average 16.9 - 17.1 Volts.

very scientific about this!   laid it lengthwise on the lawn, faced the sun, propped it up with a soda bottle to get an angle  (should be close to perpendicular),  clipped the test leads to a piece   of cardboard to help keep things organized. 

 

then I got a tail light bulb from the junk box in the car....   got it to light using a small screwdriver  to make the connection.   amazing that it's almost instantly hot!  (holding the bulb in my fingers)      then I tried for a current reading....   on the small filament i got 1.5 amps. 

 

I realize different panels will read differently....  small manufactoring differences, possibly damage, dirty, shaded etc.      so I 'think' my Voltage reading is good....  it was mostly sunny with some high thin haze and I watched it for about 1 1/2 hours  (when I wasn't playing with amperage)

 

I've read that output will drop with age....   possibly 80-90 % rated output.

if my reading is good, then this one has about 70% output (compared to the old HP test), but that's probably right.... it IS 24 years old.

 

anyhow,      Watts  =  Volts x Amps            W =  17 x 1.5      W = 25.5

now figure a 4 hour solar window,  I could average 100 watts per day.

that's not much, but would power small lights, maybe a radio too.

 

I'll check the other panels when I get home next week,  also I'll look for my notes on power usage... I was playing with a Kill-a-Watt meter.       

thinking if I go a/c, and using small stuff, put it all on a power strip and use one outlet on an inverter.  (have 400 watt inverters for the car & van)...   get set up with one panel to start... then add the others in.      have a 12 v cigarette lighter plug for DC....    and play with the LED bulbs for lighting.   you're right!     this could be fun!      

well, ttyl!   Dave

 

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[12vman]

Hi Dave..

The open voltage test looks really good! Each "New" silicone cell
produces real close to .55 volts. (33 x .55 = 18.15 volts) I'd say
that's up to par. If you get another chance, Put your amp meter on
say.. The 10 or 20 amp setting, And "Short" the panel out with the
meter in full sunlight. I'd be curious to know what that reading is..
(Short Circuit Current) The reading that you have is the current load
of the bulb. The short circuit test will tell you how much current the
panel can provide. Your meter will be the shunt. I believe that you
are under estimating the panel..

Let's say it shows 3 amps on the short circuit test. Your voltage is
17 volts. (17 x 3 = 51 watts) I'll bet that bulb was bright! You only
loaded it down a small bit or maybe half! The short circuit test will
give you a close estimate of the true wattage..

Do this test with all of them. Get the open circuit voltage and the
short circuit current reading and then you can figure the wattages.
This test isn't perfect but it will get you within the ball park by
around 5% if done on a real sunny day at around noon. The calculated
wattage will be a bit higher because the true current reading will be
a little less at the normal operating voltage. (Around 13.8 volts)

Have fun, My friend.. You've just begun.. ;)
~Don

[David Haig]

hey Don....   I tried the testing again ....   clear, sunny day  around 1 pm with sun high in the sky...  panel almost flat (just propped with soda bottle on it's side)

voltage started at 18.4.... gradually dropped to 16.54...  fluctuated and seemed to settle around 16.60 - 16.61 Volts

current (using 10 amp setting) fluctuated between 2.01 -1.76..... seemed to settle for

1.94 - 1.96 Amps

that would be around 32 Watts.       I checked the HP cd again... the Rated Pmax was 35 W so I'd say this is good for it's age!   

 

also, I played with shading the panel...  held up my notepaper and with maybe 6 of 33 cells shaded ....   the current dropped to 0.46 Amps....    just demonstrating the importance of having a clear area with no shading!   

I hope to be home Wednesday (taking my meter with me) and if the sun cooperates I'll test the other 2 panels.

 

Question on Batteries:     I've read about how in rural Mexico people use a car battery with a solar panel (no controller) and just power a light or two and a radio.   This is low usage, regularly recharged with regular usage so no overcharge.   Kind of like I do with the van lights, and I see you used a car battery at first.

a step better would be a deep cycle battery...  and I found a Marine deep cycle 12 Volt for $47...   (75 Amp-hour).   these are readily available, would be 1 battery (easier than using 2 6-volts),  AND I've read that people tend to destroy their first battery as they're learning how to manage it...    think this would be a good battery for a starter system?

well, hope you all enjoy your weekend..... take care!     Dave

12vman <wind...@aol.com> schrieb:

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[David Haig]

Hi Don......   back from NY.....  made it home and spent a couple of days doing yardwork....  mowing, chopping, weeding.....   camped out in the backyard 2 nights.     also made time to check out my other 2 solar panels.

the first (the ancient looking one) is Product of Energy Sciences Inc. of Gathersburg, MD  serial #1035.      no other labels.

I hooked up the DMM for voltage and got '-19.46'   .....  realizing this meant I had polarity backwards I switched leads.  that identified the positive & negative leads for me.      also at first there was no reading... I checked and there was something like rubber cement over the contact... the wire had broken off and just the cement was holding it.... I scraped the cement back and exposed a small lug to attach the test lead to.  

test results:  V  19.80 - 18.56     A  1.28- 1.30    possibly 33 W

 

the other panel, polycrystalline i think (not individual cells)  had no markings anywhere on it...   had a length of house wiring hooked to it.  

test results:   V 19.16- 18.8     A  2.29       possibly 43 W

 

so with all 3 panels combined I might have 108 Watts output. 

 

I was thinking....   maybe use the one panel in the city to play with .... get familiar with it... and use the other 2 at home on another battery.    on the 12 Volt Yahoo group I read of one guy who didn't want to bother with running wires... so mounted his battery on a luggage cart... wheel it out and plug in the panels.... wheel it in and plug in the loads.

 

well, ttyl!  Dave

 

 I hope to be home Wednesday (taking my meter with me) and if the sun cooperates I'll test the other 2 panels.

 

Question on Batteries:     I've read about how in rural Mexico people use a car battery with a solar panel (no controller) and just power a light or two and a radio.   This is low usage, regularly recharged with regular usage so no overcharge.   Kind of like I do with the van lights, and I see you used a car battery at first.

a step better would be a deep cycle battery...  and I found a Marine deep cycle 12 Volt for $47...   (75 Amp-hour).   these are readily available, would be 1 battery (easier than using 2 6-volts),  AND I've read that people tend to destroy their first battery as they're learning how to manage it...    think this would be a good battery for a starter system?

well, hope you all enjoy your weekend..... take care!     Dave

 

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[David Haig]

hello again!   been doing my homework....   read the Battery Book for Your PV Home and took notes,  now I'm working my way thru The Solar Electric Independent Home book.   It's starting to come together.... makes more sense when you can look at the hardware, and read what directly applies to your situation.   One part I got 'stuck' on was the charge controller...  articles in HomePower are good, I kind of study them... and they include diagrams..  but one I saw had 3 sets of connections...  2 for panels, 2 for batteries, 2 for load.....  mine has 2 sets....     2 for batteries, 2 for panel/load    

so I'm guessing the newer ones have the 3 sets and have the low battery disconnect...   where my old one just ran the load off the panels, or the batteries....  and you had to monitor it to prevent deep discharge.....  am I correct?

 

u asked for details:   this is a Trace Engineering Solar Charge Controller

Model C-30A   automatic 12/24 VDC Selection       automatic no light disconnect

30 amp capacity at 12 & 24 VDC

Has Equalize Switch  (a small slider switch)  left - Normal   right - Equalize

(Caution: EQ position defeats voltage regulation)

 

LED indicator:  on- active array   slow flash - charging       fast flash - equalization                off -array inactive

 

inside cover: 2  battery trim pots with test points   low & high battery

 

connectors:  (left to right)      battery positive     30 amp fuse  (glass)     panel/load positive

                  

                                           panel/load negative                                battery negative  

 

outside case: has equalizer slide switch          red led indicator light     and a small white indicator?   (it is hooked up inside)  

ttyl!  Dave

David Haig <hai...@yahoo.de> schrieb:

[David Haig]

hey Don.....   been playing around and collecting stuff.     I posted a picture of my pv test setup.   I went and got the marine deep cycle battery...   I read in New England Solar that if you only have one battery that's good...    and if I really mess up I only burn a $50 battery instead of $220 worth of T105's.     I've been testing the battery, then using one load at a time and logging it, then testing again to get an idea of what I can use.   an example is a 20 inch box fan running off an inverter.....   it works.... but has a strange sound to it and doesn't seem to push as much air....   and it's an energy hog.     I have a small 12 volt fan from the van to try next.  

found a good source of 12 volt stuff at the Flying J truck stop....   power leads for the lighter plug, leads with alligator clips to attach directly to the battery, lights, fan, and a cooler.    also picked up a switchable lighter power supply at a flea market....   can select a number of voltages.

while home I checked the old van battery and found it was down to about 80%... cleaned it up, added distilled water, and hooked up one panel for about 4 hours.    the next day I tested it and it was fully charged!    hey,  this stuff works!!

I made it to the MREA fair in Wisconsin....   and found one vendor with a setup like what I had in mind....   several small panels charging a marine deep cycle battery, and using 12 volt power leads and an inverter he had a small fan, a couple of lights, and a laptop.  i posted that picture too... pv demo.         I was walking by as he was setting up and went wowwww!!  

had a good time.... made it to several workshops....  volunteered with setup and did a 3 hour shift on garbage patrol.    also made it over to the strawberry festival.  I'll post other pictures on the main chapter website.

I also have a small 5 inch tv, and picked up a heat lamp with a giant clip for mounting...  plan to try a 13 Watt compact flourescent bulb with that.   hmmmm.....  light, tv, fan....  I'm getting there!   ttyl!  DaveH

 

 

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