Ok, the sky was perfectly clear today. Testing done around 1 pm, First test was for Short cct current...
I did see 4.6 amps briefly but it stayed at 4.4 mostly.
in order for this to be a 100 watt panel with a power point voltage at 17.1 would mean it needs to be tested with a 2.9 ohm load So...look at this I dialed a rheostat right down to 2.9
With the rheostat hooked to the panel guess What? The voltage collapses, falls flat on its face...6 volts 6.07 to be exact. A third of where it should be holding at.
Give a man a gun, and he can rob a bank. Give a man a bank, and he can rob the world.
So since I can adjust my load to hold the voltage at 17.1 I did just that to get what this panel should be rated at. I got 4 amps at 16.98 volts (close enough for me)
So 67.9 watts would be a fair ratting for this panel. In fairness even though it was a bright clear day, I know I can milk a little more power out of this panel on a spring or summer day..a little more, not a lot, I expect when I test this again on a summers day I will get over 70 watts.(maybe 74-75)
I will do actual battery charging at that time. I am thinking from the numbers seen so far, under actual battery charging conditions I could/should get roughly 55 watts from the panel.
Give a man a gun, and he can rob a bank. Give a man a bank, and he can rob the world.
Is this a usual number to count on for battery charging; ~ 1/2 the listed wattage?
Oh.. that's a loaded question...I am going to have to go all Bill Clinton on you and say: it depends on what your definition of "is" is and your definition of "battery charging" and Doctor who on you with a time based description of "usual" and "wattage", Im not up for that tonight or in one night, so the quick answer is No that's not usual, pretty crappy , would be ok if it was honestly rated as a ~73 watt or so panel and cost 50 bucks. Likely usual for all coleman type panels.
A more fluid answer begins with what is proper battery charging? and that starts with the data sheet from a manufacturer of batteries.. Go..Go..Googler......poof..( what a time to be alive, info at the touch of your fingers) http://www.trojanbattery.com/pdf/datasheets/T105_Trojan_Data_Sheets.pdf look it over...if the no answer was good enough say so...
Give a man a gun, and he can rob a bank. Give a man a bank, and he can rob the world.
I had set this panel up against the house, under the eves but tucked behind some stacked firewood last fall. In other words, out of the sun, no rain or snow fell on it, and nothing has touched it until I pulled it out a few days ago. I welded up a steel frame to make a portable solar panel array for the property, and put this panel on the rack beside some "real" panels.
we had some great sunshine a few days ago, so I thought I would finish testing this unit, remember this unit is brand new, I just unboxed it last fall, the only element its been exposed to is temperature.....something you would expect a panel to be able to take.
Im short on time so I am just going to cut to the chase. I couldn't get 50 watts out of this POS under real battery charging. Nearly 20 year old 75 watt panels, from a real manufacturer beside it perform way better. But worse than that this unused panel is already starting to fall apart, as the picture shows. On one side, and one end, the adhesive that is supposed to bond the glass to the aluminum frame, keeping water out, is breaking down!! Major failure!! I couldn't hit the same numbers I got testing this unit last fall! So its already going down hill....
I looked at reviews of this panel on line last fall, and again this summer.......I think they are all BS....now I know my sample size is small being just one unit, but what are the odds I got the only unit with poor electrical performance, and mechanical failure....
its people buying and using crap like this that gives solar panels a bad rap and has people saying they don't last or perform well.
I will keep this unit on the rack and make sure I point it out to everyone that's over and is thinking about buying these over priced poor performing panels, people may not understand evaluating electrical performance, but everyone can see when something is falling apart!
I am not really going to investigate this mechanical break down further, it could be the adhesive, but I suspect the quality, and gauge of aluminium used, I think this panel has now seen a full thermal cycle going from -30 something in the winter, to + 30 something in the summer and that caused the rail to pull out of the adhesive, just a WAG on my part, don't really know.
Give a man a gun, and he can rob a bank. Give a man a bank, and he can rob the world.
Thanks for sharing! So I guess they're not even worth having as "just in case."
I would say no, not worth having just in case. If its kept as a closet queen, then maybe it will work for you if you pull it out to use briefly. Based on my experience I would say left out side to the elements expect it to begin deteriorating, these are not a cost effective,long term solution. While I did not buy the charge controller recommended for these, I have a friend that did, did against my advice. Now a few years later he is wondering why his batteries are performing so badly ( deficit charging) in his work van .
I love lots of coleman products, especially propane products, but I wouldn't advise anyone to spend coin on the solar products, In fact if you couldn't get good pricing on 12 volt panels, you would be further ahead to buy a 60 cell 250 watt panel, power point around 30 volts dc at 8.4 amps. You can find the price around 75 cents a watt so that will cost you 187 dollars as opposed to 220 for the coleman so you save 33 dollars but get a panel that would be rated for 8.4 x 17volts = 142.6 watts If used for 12 volt charging. So you pay less and get way more power!!
You also get the benefit of voltage to burn, no need to worry about voltage drop...you can have your panel hundreds of feet away from you batts if you wish, just size your wire for current capacity.
Give a man a gun, and he can rob a bank. Give a man a bank, and he can rob the world.
75 cents a watt, new or used? I'm seeing used on kijiji for 74-78 cents.
Not sure why he is charging tax, maybe a business?
New, check PM.
Give a man a gun, and he can rob a bank. Give a man a bank, and he can rob the world.
I use a panel. The best way to check how it's performing is to buy a cheap multimeter w/up to 10amp throughput measure capability.
The following table is worth noting as it will tell you the 12 volt battery charge condition and I use mine for both batt's I have. I.e.:
12 VOLT CHARGE CONDITION TABLE (Multimeter Reading):
VOLTS DC % Of Full Charge
12.6 FULL
12.5 90 Condition-GREEN
12.42 80 GREEN
12.32 70 GREEN
12.2 60 GREEN
12.06 50 GREEN
11.9 40 GREEN-Border
11.75 30 RED
11.58 20 RED
11.31 10 RED
10.50 0 DEAD
Surprising how quickly the capacity of the battery diminishes on smallest of lower readings! Anyway, use your multimeter on amp setting to ensure the rate of charge on a battery with less-than 12.42 volts dc is at minimum sending at least 2 amps (depending on Panel wattage), and on volts dc setting, sending a minimum of 13.8 volts through to the battery after 5-10 minutes. During 75% or more direct Sun on the panel.
Thanks for info.
Bob Scott, if that chart is working for you, good. If anyone gets on the googler and looks up "12 volt battery capacity charts" Pages of them will come up...some from manufacturers, some from battery distributors, and some I suspect are purely made up. I found the chart you posted and it is widely used, and I am not saying its wrong there are too many variables not stated on charts that if known could make every chart bang on, such as temperature, age, stratification of battery acid, internal construction, under load or resting....the list goes on.
I use a different list that I have found to match my experience if the goal is the longest life of the battery....The biggest difference you will note is how it shows the faster drop off that you have observed at the low end, and its overall more conservative in measuring battery capacity.
But regardless of what chart is used I believe it equally important how you charge, and that starts with the controller you use, and if it doesn't have independent settings for Bulk, absorption, float, and equalize (3 out of 4 is ok) then its junk, I didn't include temperature compensation as I just don't find that required in 90% of cases and don't use it myself even though I have the probe, and I would want to make sure the controller can hit 15.3 or greater for equalizing and up to 15 for bulk (I go to 14.9 myself) and use 13.5 for my float.
So many cheap chargers don't hit these voltages and you wind up deficit charging your batteries, it wont be noticed at first....but as time goes on ( measured in years) it will....
Remember I am suggesting my chart for long battery life if I was going for shorter battery life but maybe greater power out per dollar spent, in other words flogging the batteries hard, and there are reasons you might want to do that, then your chart I think would be the one to use.
Give a man a gun, and he can rob a bank. Give a man a bank, and he can rob the world.
can you suggest a quality manufacturer of solar panels and a controller that has proven itself to you?
The dark arts of electrons and protons is definitely not my forte!
Short on time right now, but give me a day or two, and I will PM you a model, and the specifics of why I like it, and the place in Edmonton that last quoted me the best price.
Give a man a gun, and he can rob a bank. Give a man a bank, and he can rob the world.
May I get your recommendation too?
