SOLAR panel effiency - debunking myths ?

Ed,
The 12 Amps is being produced by the solar system :-)

As can be seen in the two gauges situated below the Steca regulator, only 5 Amps is charging the 14.3 Volt battery system

Maîneÿ . . .

So where's the other 7 Amps going?

;-)

No Theory ok. Then a question:

Do you know how the manufacturer arrives at the power converted by their solar panel? Please quote the numbers, they publish, to arrive at this power.

Then we'll take it from there.

If the two analogue gauges read the battery current and voltage then that's 73W into the battery.

What's the problem ?

What is the digital gauge measuring ? Is it calibrated properly ?

Maths ?????? So where's the other 7 Amps going? - Yes I would like this one answered

Watts = Amps x Volts

Does this mean the system charging at 5 amps @ 14.3 volts equates to

5 x 14.3 = 71.5 Watts?

and anyway if it was charging at 12a it still stumps me :-)

12 x 14.3 = 171.6 Watts

Its all too confusing :-)

Cheers Tony

Tony,
your statement: "Does this mean the system charging at 5 amps @ 14.3 volts equates to 5 x 14.3 = 71.5 Watts? "

Yes, that is close enough to the performance of an 80 watt solar panel, their voltage is just a tad higher, their Amp output is a fraction less and giving ~80 Watts.
So it's not confusing at all, because you do understand it :)

Maîneÿ . . .

Hi Mainey, I am not fully au faye with solar systems but the photos in your post are the proof in the pudding so to speak. What I can't understand is the "loss" of efficiency as all the figures mentioned are at the solar panel not the battery. I am right in saying that if you were pulling 12 amps out of the battery at the same time as the solar panel is charging you would be depleting the battery by around 7 amps per hour or would the fact that there is a load on the battery allow it to take on the power more effectively.

Mark,
it's explained further down, just put it up now, so your question is good and makes good sense to me, obviously not to some others.

Basically;
Solar panels are producing 12 Amps
Battery is fully charged @ 14.3 Volts
Amps going to the battery system is only 5 Amps

Reasoning: what you don't see is the fridge is also running at the same time.

If the fridge was not running the battery system would only be 13.6 Volts and would be trickle charged only with about <1 Amp.

Maîneÿ . . .

I’ve put up a photo of a solar system producing the maximum Amps it was designed for by the manufacturer after reading "in a typical small 12/24-volt system most modules produce about 70% of that apparently claimed"

Maybe the word "most" in 'most modules produce' is in reference to the elcheapo, budget priced 'copycat' crap panels available now, some are just about worthless.

If that's considered a 'point' then it is, as I'm no longer selling them.

Maîneÿ . . .

Steve,
Yes, you have made a very valid point, most solar panels have a warranty that they will still be outputting in excess of 80% after 20 years, that's because they put out well in excess of 80% when new.

"MOST if not ALL panels have an 80% of output warranty over 20-30 years now .. "

Maîneÿ . . .

Precisely..... 171.6 Watts

However, it must be said that many panels actually can produce somewhat MORE than their rated output for brief periods, that is when they are cool and get suddenly hit with full sunlight.

Notso,
you can't use the 'maths' you have shown to prove anything at all, other than an answer that has absolutely no relevance at all to the Watts or Amps put out by a solar system.

hl, of course you will get the ‘number’ 171.6 by multiplying 12 and 14.3, but that number has NO (nil & zero) relevance in any way at all, to the solar output of a solar system .

The only known facts are: 12 Amps and 203 Watts
the Voltage is a completely unknown factor in this case !

The Voltage number your using (14.3v) is only the surface voltage of the battery
It’s not the charging Voltage of the Solar system, which is ~17v

Maîneÿ . . .

I beg to differ, Mainey.......

Once the panel is connected to the battery and it is in full charge mode i.e. the regulator is not in "float" charge mode, the panel and battery voltage will be the same and it is absolutely valid to calculate the wattage that way!

Trust me :-)

hl

hl,

When the battery is fully charged it's maintained @13.6v on 'trickle' mode
maintaining the 13.6v in the battery *only* when battery is NOT running any appliances.
Boost charge voltage = 14.4 Volt
Equalization charge = 14.7 Volt

Maîneÿ . . .

Once again Mainey proves he has no idea what he's talking about. Seriously dude, where exactly are you getting 203watss out of this set up? Nowhere.

"hl, of course you will get the ‘number’ 171.6 by multiplying 12 and 14.3, but that number has NO (nil & zero) relevance in any way at all, to the solar output of a solar system . "

What are you on? Since electricity was discovered the power output has been arrived at by multiplying current by voltage. It's only in your universe that your logic works (if there's any way to call it logic).

Glenndini,

very easy,
I get the 203 Watts because it is written on the back of the panels


You say; "Since electricity was discovered the power output has been arrived at by multiplying *current* by *voltage* "

so output is:
(current) 12 Amps X (voltage) 17 Volts = 204 Watts

yeahh your right
Sharp's wrong, it says 203 Watts, and they say numbers never lie :)
maybe it should be, 12 Amps x 16.9 Volts = 203 Watts

Maîneÿ . . .

"you can't use the 'maths' you have shown to prove anything at all, other than an answer that has absolutely no relevance at all to the Watts or Amps put out by a solar system. "

Sometimes it's so easy to see why many people here have tried to explain basic electricity to Mainey, but we've all given up.

Good to see you have not changed Mike,
so what brand of solar system did you buy recently that you have posted dosn't work in overcast conditions ??

Why won't you advise guys what brand to avoid ??

Maîneÿ . . .

Oh dear........

Do yourself a favour.. either just stop displaying your ignorance about Ohm's Law, or, just measure the voltage pre-regulator and multiply it by the current displayed... and there will be your answer. Then you could inform everyone with facts, not fiction.

Now, you should be able to handle this?


Hl

hl,
I actuall said; "It clearly shows it’s capable of delivering * 12 Amps *
as per the photo, which is ~100% of the manufacturers claimed output
and therefore obviously well above the 70% or 80% claimed by some ‘information’ sources"

I never compared Watts with manufacturers specs at all.

I'm not measuring anything other than Amps, I'm comparing Amps with manufacturers specs.

Maîneÿ . . .

Dave,
This is another photo of the same system, this photo is showing it's actually producing 11.9 Amps @ the solar system, 3.5 Amps is charging a 13.8v AGM battery system.
Remember this system is laying horizontal on the roof of my vehicle.

Image Could Not Be FoundMaîneÿ . . .

Andrew,
Yes I have a reference/link to where this 70-80% is mentioned, look at the link in my original post, it states: "In a typical small 12/24-volt system most modules produce about 70% of that apparently claimed"

That is just one, it's mentioned in members "blogs" also

Maîneÿ . . .

Ed,
Your post shows you know absolutely nothing about solar power :)

Maîneÿ . . .

Does that mean that you're not willing to put up photos which would demonstrate the true efficiency of your system????

;-))

Ed,
as I've said you know absolutely nothing about solar power, the original photo shows 12 Amps produced @ the 203 Watt solar panels, that's the proof you seek.

Maîneÿ . . .

I think you need to go inside out of the sun or let go of the wires.

cycadcenter,
what don't you understand ????

Maîneÿ . . .

The only real way to test this is to put a variable load on the system then load it up to see how many amps the thing supplies whilst maintaining the voltage.

Other than that you're just pulling figures out of the air to support your case.

Notso,
Don't you believe the Amperage numbers shown on the Steca regulator in the photograph ?

It does clearly show the Amps produced by the solar system

Maîneÿ . . .

I know it's been said before but "So What", the amps says nothing about how many watts are being produced.

So let's look at Voltage and Amps being produced whilst delivering said amps to a variable load.

Notso,
This thread is only about the rated output produced by a solar panel.

If you look at my original first post it reads:
"After reading some 'information sources' that claim solar panels will only deliver about 70% to 80% of the manufacturers rated output, I thought I should put up a photo showing the solar output available from my system, which is rated at 203 Watts"

Now you post: "the amps says nothing about how many watts are being produced"

Obviously your unaware it's *Amps* that will charge a battery and *NOT* Watts.

Maîneÿ . . .

Yes, you're right.... I know absolutely nothing about solar power ;-)

So, since you know it all, can you please explain to me what is so efficient about a 203 Watt panel feeding a 5 Amp load ??

After all, you are the one who has started a thread about solar panel "effiency" (whatever that is, but I'm assuming you meant "efficiency";-))

Where is the efficiency in your photos???

So you have a 203 Watt panel which produces 12 Amps @ 17 Volts... Wow!!!

they all do that :)

:)

So the rated output of your panel is 203 watts, the actual output by your own figures is way off that. I keep trying to tell you, and I know it's hard to understand, but you can't possibly say you have debunked a myth by only quoting an amp figure.

If you want to debunk a myth, get scientific instead of emotional. Politicians use emotions, if you want to claim any scientific knowledge give us facts or go and get back on whatever it is that makes you feel good.

Ed and Notso,
Question is asked: "So, since you know it all, can you please explain to me what is so efficient about a 203 Watt panel feeding a 5 Amp load"

Yes, I can do that just for BOTH of you

First you have to look at the battery Voltage it is ... 14.3 Volts

The Solar *regulator* NOT the solar panel, is sending 5 Amps of the 12 Amps available, into the battery.


What you don't get to see in the photo is the fridge is RUNNING
That's why only 5 Amps is going to the battery, the "missing" Amps are running the fridge


Now I hope you understand how solar power works, my battery system remains fully charged even when the fridge is running, because the fridge runs off the solar system output when available, and no they all don't do that at all.

If you believe the photo is "emotional" and not showing 'factual' information then I'm sorry

Maîneÿ . . .

Here is the published spec to illustrate a point:
One can apply the same reasoning to most panels.

Model: BP380J
Max Peak Power (MPP): 80 Watts
Voltage @ MPP: 17.6 V
Current @ MPP: 4.55 A
Open Circuit Voltage: 22.1 V
Short Circuit Current: 4.8 A

What does this spec mean ?

1. The load and short circuit currents are almost the same because a solar cell acts like (is) a constant current source (compared to a battery which is a constant voltage source), These two sources are duals. The normal state of a constant voltage source is to be open circuit and a constant current source is to be short circuit. If you short circuit an ideal battery the current is infinite if you open the loop on an ideal constant current the voltage rises to infinity because it tries to drive the same current through an open circuit (This is why high power constant current sources are extremely dangerous) and finally the internal impedance of an ideal constant voltage is 0 ohm and the internal impedance of an ideal constant current source is infinite.

The solar panel will take the voltage of the battery that you put on it it acts like a constant current source in a limited range of voltages.

2. The above spec tells us that 80W (17.6 x 4.55) is obtained with a voltage of 17.6V - normal charge termination ends at 13.6V at that stage the cells will be delivering 62W and this is usable.


3. Will I get 80W from this panel? Possibly, if I terminate with a 3.9 ohm load!!!
And then what?

4. Does the open circuit voltage of 22.1V mean anything here ? No. But the controller better be able to handle that voltage at its input when it terminates the load current (equivalent of short circuiting a battery).

So how do you explain the "12 Amps" shown in my photo above using your 'theory' and 203 Watts ??

Maîneÿ . . .

"ed and Notso,
Question is asked: "So, since you know it all, can you please explain to me what is so efficient about a 203 Watt panel feeding a 5 Amp load"

So now we have a 203 watt solar panel delivering 12 amps, which I always accepted??

So again I ask the question, "How many watts" as neither you, nor I can state that with any degree of certainty with what you have shown us. Since you made the assertion, then it's up to you to prove it. Making "motherhood" statements doesn't prove a thing.

Ahhh, OK,

So, you have 5 Amps maintaining the battery system at 14.3 Volts, and 7 Amps running the 'fridge.... very good ;-)

Now, where's my (el cheapo Chinese) calculator......

Let's see... !4.3 Volts X 12 Amps = 171.6 Watts

By my (el cheapo Chinese) calculator, 171.6 Watts delivered to the batteries / load from a 203 Watt panel, equates to about 85% efficiency...

So what "myths" exactly are you trying to debunk??

:)

Notso,
You now post; "I ask the question, "How many watts" as neither you, nor I can state that with any degree of certainty with what you have shown us. Since you made the assertion, then it's up to you to prove it"

Yes, I've always stated 203 Watts, it's printed on the rear of the panels.


Ed,
You obviously don't understand English too well
I've previously stated the Voltage is * NOT * 14.3v - but ~17 Volts

So now multiply 17 Volts x 12 Amps and you get 204 Watts, yes simple math

Obviously your chinese calculator comes from the same factory that makes the crappy solar panels that don't work either

Maîneÿ . . .

Now Mainey, you can't have it both ways, the 17 volts you're talking about is pre regulator, the amps you quote are post regulator. The voltage post regulator appears to be 14.3, so I think you should be consistent and maybe tell us how many amps there are pre regulator??

Then we may, just may, believe that on this particular occasion the panel, just may have, delivered 203 watts.

Then we can start another "discussion" on how it goes averaged over time when the sun isn't overhead etc etc etc??

Notso,
I assure you the Voltage AND ALSO the Amps are *both* pre-regulator.

The Voltage is the AGM battery system

The Steca website and anyone using a Steca reg will confirm this too

Maîneÿ . . .

Se we're back where we started....

Maîney, by your own published figures, your 203 Watt solar SYSTEM (ie, panel & regulator) is delivering 171.6 Watts to the batteries / load.... Best case scenario, I would think..

You can try it on your expensive Swiss made calculator if you like, and I'll bet that it still comes out at around 85% (efficiency)...

Yes, I know full that the panel rating is at 17V, but the SYSTEM is supplying a 14.3V load....

And no, you cannot separate Volts, Amps, and Watts, as they are all inter-related
(as you should know only too well)..

So I'll ask again...

Which "myths" exactly are you trying to debunk?

;-)

Ed,
sorry but 203 Watts, 12 Amps is not 14.3 Volts

You forget the fridge is also running too and drawing power

Where does the fridge draw it's power from ????

You have not made any allowance for that in your calculations

Maîneÿ . . .

Have you ever seen a dog chasing it's tail, no sense to it really and that's about how this thread has turned out.

AH well gave us all something to fill in the afternoon I guess.

Hi Mainey


Jeramy has made the valid point
Panels are rated usuallly @ about 17v [max ouput]
!7v into 203 watts gives about 12amps
The panels also give a noload voltage of about 21v .
Many believe they should get the rates amps @ 21v [ not @ 17v as above]
12amps by 21v =252 watts
203 w /252w = 80%
But what most think is if the load voltage around 14v
Then 203w /14v =14amps again 12/ 14 = 85 %eff
Or taking it a step further if the load voltage is 12v , then 203w / 12v =17amps now in their mind 70% eff

Solar panels are basically a constant current source, the available current is dependent mainly on sun brightness
Load voltage is not really relevant except @ open circuit [no current]

The current @ 0v due to a short circuit is only marginally higher then current @ rated output
The panel should have an ouput curve this will show max output[rated] is @ around 17v

yes,
"Jeramy has made the valid point ...... 17 Volts into 203 watts gives about 12 Amps "

I make the exact same point using a photo

Maîneÿ . . .

You cant just show a picture of the amp output and claim to know the wattage.

In the picture you should connect a multimeter to the output side of your meter to show the working voltage, Then using the voltage and amperage readings anyone can accurately calculate the wattage.
Without displaying the working voltage you have proved nothing regarding the wattage of the system.

I have a 80w panel that puts out just over 5 amps through the regulator, reading the comments below it seem you are working things out at 17 volts, this would mean my panel outputs 85 watts.

However my meter unlike yours, simultaneously displays the voltage, amps and the wattage. so I could clearly see that the real output of the system on the given day was around 70 watts.

I'm not that interested in the Wattage or Voltage at all because it's *Amps* that charge a battery.

The more Amps produced the more efficient the system, the maths behind how the Amps are produced is not relevant.

Sure the panel manufacturer claims 203 Watts @ ~17 Volts

However, I claim 12 Amps is produced @ solar system

Maîneÿ . . .

Actually you are interested in the wattage,
This whole thread is about "manufacturers rated output"
Go back to your first post, that's what you wrote.

In case you don't know....
Solar panels are rated in WATTS not AMPS

12 amps is 100% you say, my cheap 80watt ebay panel is good for 5 amps which by your thinking would make it over 100% efficient - that's better than your panel


As many others have mentioned you clearly have no idea what you are talking about, Obviously everyone but you understands how solar works.
The fact that you are standing your ground after being repeatedly shown you are wrong is quite hilarious.

outsider,
In my original post I stated:

"It clearly shows it’s capable of delivering 12 Amps, as per the photo, which is ~100% of the manufacturers claimed output, and therefore obviously well above the 70% or 80% claimed by some ‘information’ sources"

I clearly used the terminology:
*AMPS as being ~100 of manufacturers output*

I did not suggest Watts, or compare Watts with manufacturer’s specifications.
Everyone here is using the terminology Watts, I clearly used the terminology Amps.

Yes, I'm aware panels are rated in Watts, I've even said that previously, but as I've also said those Watts don't charge a battery, Amps do!


If you believe your "cheap 80watt ebay panel is good for 5 amps" then please advise the brand and model you have bought, as Sharp and even BP 80 Watt panels are not rated @ 5 Amps, (only ~4.5 Amps) even in perfect testing conditions, let alone in the real life conditions you would have tested your panel.

Maîneÿ . . .

I don't believe, I know, I have tested it.
That's something you haven't done because you obviously don't understand basic electrical principals.
My measurement are correct,
Yes it is 5 amps but it is actually only 70 watts because it is measured in relation to the "true output voltage" and not the imaginary 17 volts you are using.
I can use your imaginary 17 volts too, 5 x 17 = 85 watts, see - But I know is not correct, Just as your claim of 203 watts is most likely incorrect.

On your panel it actually says 12 amp output ? or dose it say 200 watts output?
Your "clear use" of the terminology amps is not the manufacturer’s terminology
The manufacturer’s specifications is in WATTS, you can't say you have matched their maximum rated output when you are not using their ratings.

Everyone here is using the terminology Watts because that's the correct terminology, you're the only one talking in amps.
Do you really believe everyone else is wrong and you are right?
Why do you think there are so many fruitless posts here trying to explain this to you.

Power charges the battery
Amps is the measure of current it is being charged at, amps doesn't charge anything it is a measurement.

Power is measured in Watts,
Eg. a 60 watt light bulb, 300 watt inverter, 800 watt generator or amazingly a 80 watt solar panel.

Many have tried to show you the error in you thinking but like a true fool you blunder on.
how you can just keep babbling on about it is beyond me.
I pity anyone taking you technical advice.

outsider,

Question:
Again I ask you what brand is this 80 watt panel you have tested that's rated @ 5 Amps ?

I ask because all 80 Watt rated panels I'm aware of are only rated @ ~4.5 Amps

You ask:
"On your panel does it actually says 12 amp output ? <-( YES )
or dose it say 200 watts output ? <-( YES - 203 Watts )

You then say: "Amps is the measure of current it is being charged at, amps doesn't charge anything it is a measurement"
Yes, as I say Watts does not charge the battery Amps does
(have you ever asked anyone how many "current" is their Alternator or generator, of course not - you ask how many Amps)

Maîneÿ . . .

Re: Amps is the measure of current it is being charged at, amps doesn't charge anything it is a measurement


I gotta say this:

Bravo!

This is the first time IV'e heard someone distinguish between current (in amps) and the charge,

Amps is a measure of the rate of charge movement (dQ/dt) and it does not flow. Charge flows.

Jeremy

Thanks Jeremy.
I only know the basics but it is fairly easy to understand.

Mainey
I didn't say my panel was rated at 5 amps. When tested, its output was just over 5 amps
So yes I have a panel that if you look at only the amps and nothing else, It will exceed it's rated capacity. maybe I should take a photo.....
I not going to pull it out of the van to see what brand it is, I bought it from this guy
BTW, I have given you that link before and you bagged it because I said I was only getting 70 watts out of it but now with your voodoo Amp logic it must seem very good.



A few posts above you wrote this quote "Sure the panel manufacturer claims 203 Watts @ ~17 Volts

However, I claim 12 Amps is produced @ solar system "

What they claim and you claim are different.

Batteries store electricity, The amount of electricity in a battery is measured in volts and amp hours. When you charge a battery you are putting electricity back into it, that is what it stores.

When you discharge a battery the volts go down, when you charge it the volts go up, are you sure it is the amps and not the volts that charge the battery, Surly the volts must have something to do with it don't you think.

I'm gonna take this advise

outsider,
I did a quick search for the link in previous threads, because I don't remember the company at all, I refuse to believe "I said you were only getting 70 watts out of it" reason being, there is absolutely no way of telling from the website information how you would be getting only 70 Watts from an 80 Watt panel, so I won't argue with you or stoop down to your level.

Maîneÿ . . .

Hi Mainy

"Maîneÿ . . . posted:
Notso,
I assure you the Voltage AND ALSO the Amps are *both* pre-regulator. """

Now you are either confused or your confusing every one.
By pre regulator are you saying the volt & amp readings are from the panel side of the reg.???


If so Then again you prove you have not got a clue AGAIN

THE REG WILL Be showing the battery voltage [load voltage.]
It must do to control the charge.
The amp readingis isthe amps flowing thru the reg .

oldtrack,

Your the real tiger, you just won't let go will you :)

Now you ask: " by pre regulator are you saying the volt & amp readings are from the panel side of the reg "
I've answered “yes” to you previously – move on and get a life

How often do I have to tell you what is so obviously seen in the photo and my previous answers to you.

The answer is easy see, it's showing in the photo - if you look, and if you actually understand anything about solar systems - obviously you don't, that's why you keep making stupid irrational statements.

Maîneÿ . . .

Glen,
if you read my original post it refers to misinformation posted about solar power

I thought the more correct information should be also made available

Maîneÿ . . .

Maine,
I read it. Stiff.
Just go fishing or something.

Cheers
Glenn

Tony,
yes, if you attempt to do the maths with numbers that are wrong you will obviously get wrong results.
That's why I stated in the original post->
"Are there any other solar power *USERS* that can substantiate *either* side?
Using *ONLY* photos as reference, *NOT* solar hypothetical or numerical equations"

I was aware the fridge was running but believed anyone with any solar knowledge at all would also know there was an appliance running on the system too, simply because of the relevant numbers shown in the photo.

You say;
"Your 203 Watt panel is thus rated to give a 12amp Output - is that correct"

Yes, that is correct, the total output is rated @ 12 Amps
well done, go to the top of the class !!

Unfortunately some can't accept that, even though it is stated on the rear of the panels and clearly shown on the Steca regulator lcd as 12 Amps, the regulator is showing the total output of the panels, that's the entire story, where the 12 Amps then goes is not relevant to the original post anyway.

80 Watt panel is about 4.6 Amps from memory?

Maîneÿ . . .

HI Tony
Around 4.7amps
80w / 17v =4.7amps
This figure may be exceeded in extremly bright condition or with a high sun reflection from clouds, possiibly a little over 5amps.

using the exact same maths
(80w / 17v = 4.7 amps)

203w / 17v = 11.9 Amps
"This figure may be exceeded in extremly bright condition or with a high sun reflection from clouds"

Maîneÿ . . .

hehehehehe
Mainey YOU'RE so good for a laugh.
Sunday funnies.

Thanks for that - I guess what is most confusing is where the 17Volts come from to so the sum.

You go online and they are 40, 60, 80, 100, 120 etc Solar Panels all saying 12 volts?

When you look at the specs you see the Optimum Operating Voltage - 17.2 Volts.

So does this mean even though we hook them on to 12 volt batteries, they operate better at 17 volts and it is this we use to do the sums?

Tony,
Yes,
you go online and they are 40, 60, 80, 100, 120 etc Solar Panels <- rated in Watts

all saying 12 volts <- yes, for charging a 12v battery (which is 12.6v anyway)

Optimum Operating Voltage - 17.2 Volts <-Yes (not 12v)

hence you use;
'Optimum Operating Voltage' x Amps = Watts
or
Watts / Optimum Operating Voltage = Amps

Maîneÿ . . .

Mainey said "not solar hypothetical or numerical equations"

and yet he uses a hypothetical figure of "optimum operating voltage" and a "numerical equation" to arrive at this figure.

Mainey said "Using only photos as reference,"
Where's the photo of the 17V voltage being measured at the panels at the same time as the 12amps?

Glenndini,
Look at the photo, it clearly shows 12 Amps as the total produced @ solar system, if you think there is more Amps available well maybe your correct.

However, if you think less is available, then how do you explain the 12 Amps shown in the photo using your maths ??

The known facts are: 203 Watts and 12 Amps
so you tell me how many Volts if it's not ~17 (16.9)

Maîneÿ . . .

Mainey, that's the whole point of what I said. I have no idea how many volts this measurement of 12amps was taken at and neither do you.

203 watts is not a known fact. It's a figure given to you by the manufacturer which you are trying to prove is correct by using another figure given to you by the manufacturer.

We can only see one fact. A photo shows 12amps being read at some point in a circuit at some unknown voltage.

your =/ you're

Maîneÿ,

these photos of yours are certainly evidence of your panels outputting 12 amps.

Just a quick question, what's the time and location these photos were taken?

Best regards, Peter

Peter,
the first photo was taken 21/11/07 @ 11.21am
the second photo was taken 21/11/07 @ 10.55am

were taken in Busselton WA
The panels are bolted horizontal on the roof of the vehicle

Maîneÿ . . .

Hi all
The question by some is where does the 17v go say when the meter only reads 14v?

First, a conventinal solar regulator is simply a switching devise ,it is not a voltage controller.It switchs the panel output to the battery until a certain voltage is reached then it stops sending current to the battery & cycles around that pointb disc. It can incorporate 3 points of voltagecontrol ,boost charge where the contol point is about 15v for wet lead acid batterys
13.6< about 14v for float charging & a reset to boost if battery voltage falls below about 12.4v
These values are typical but depend on actual manufaturer settings
The reg will loose about 0.25<0.5 v across it. ie differance between panel side & load [battery] side. this shows up as heat in the reg
Now the mystery bit .
To charge a battery you need a voltage in excess of the battery voltage
Your simple transformer type chargers have an open circuit voltage of
17v<
When you connect a battery the measured voltage drops to the battery voltage.
This is the output or load characteristic curve.
Where does the missing voltage go?
It is lost in the battery charger.!
A solar panel has a similar output curve, needs a higher voltage than battery voltage to charge the battery, again about 17v.
Similarly the excess voltage is lost in the panel . this again could lead to the statement that solar panels are only 70<80% efficient.
12ax14v =168watts . 168w/205w = 81%
The question is not one of efficiency at all . The extra voltage is needed to drive the current into the battery.

I have endevoured to explain in a simple way, the full explanation is quite complex.

Maîneÿ,

I think the reason for the confusion surrounding the output figures of solar panels is simply caused by the effects of temperature.
Panel output is measured under standard test conditions in the factory at 25 degrees cell temperature.
Output voltage of a crystalline solar panel drops at the rate of about 0.5% per degree.
A panel in full sun on a hot day may have a cell surface temperature of 70 degrees, which would see the MPP voltage reduced from around 17.3V to 13.4V.
If the output current was measured 12A, then the output power would be around 160 Watts.

Because on 21/11/2007 at 11:21 am @ -33.66/115.3 (West Busselton) the sun struck your horizontal panels at an angle of 73.1 degrees you can multiply the 160 Watts with the reziprocal of the sine of this angle which works out to be 167 Watts.

This figure is your panels maximum output power at 70 degrees cell temperature, facing the sun fully.

The same panel would have been tested and specced 207 Watts (17.3V times 12A) at the factory, representing a power reduction of 19% in a real life scenario.
Hope this explains it pretty much.

Best regards, Peter

Peter,
Please forget the Watts and Volts for just a short time, lets just concentrate on what I actually said in my original post;

"After reading some 'information sources' that claim solar panels will only deliver about 70% to 80% of the manufacturers RATED OUTPUT..............
.............My photo clearly shows it’s capable of delivering * 12 Amps *
which is ~100% of the manufacturers claimed output, and herefore obviously well above the 70% or 80% claimed by some ‘information’ sources"

I am only using the ratings in *AMPS* (not Watts)
which in the photo of my system is shown to be 12 Amps

I'm asking you a direct question:
what's the efficiency % of this 12 Amps ???

Maîneÿ . . .

Those of us who are not dunces care. Some of us make a living caring about it.

Right on.

Its all about energy (Watt-Hours or KiloWatt-Hours).

Solar panel delivers say 375 WH per day (12.5V x 5 A x 6 H) thats it.

A small fridge uses 750 WH per day (2.5A x 12.5V x 24 H).

Conclusion: Need more panels just to keep the drinks cool.

Jeremy

Jeremy,

How do you explain the 12.5 Volts ??

"Solar panel delivers say 375 WH per day ( 12.5 V x 5 A x 6 H ) thats it"

Maîneÿ . . .

Hi Mainey,

IV'e put the explanation at the end.

Jeremy

Jeremy,

Do you refere to;
"I only know enough about 4WD's to be dangerous" :-)

Maîneÿ . . .

Right - Youv'e found the place. My answer was out of place.

ît mïght tàkê å whïlê. Thê phòtòs wêrê tåkên ôvêr 2 ykers ågö.

Hi
It a bit difficult to take a photo of something you cannot measure.!!!

But Im assure you this very thing.[output curves] applies to All power sources .]
To batterys, welding m/c , chargers, gennys ,etc
Some may have additional controls to compensate

nowimnumberone,
Yes, but plenty who want to use hypothetical math’s and watts, when I’ve specifically asked for only solar users with photo's as a reference.

I only want to know the relevance of *Amps* not Watts or Volts to the claimed manufacturers specifications, to see if any systems are as low as the claimed “70% of manufacturers specifications” which I doubt anyway.

( Using an 80W panel for an example, if you get >4.5 Amps then it has to be ~100% efficient - It would have to be ~3.6 Amps to be 70% efficient )

Maîneÿ . . .

Hi Mainy
They are not hypothetical maths

They are well established practical formulae used through out the electrical industry
If you cannot understand that by now i[it has been pointed out to you many times over the years] then you never will

I also suggest you withdraw your blog on" solar that works"
It is full of errors & assumptions that could lead many astray

oldtrack,

They must be hyperthetical, because no-one has answered the one simple question I've asked :)


If you believe there are any "errors" then please nominate the errors
The photo's tell it exactly as it is

Maîneÿ . . .

oldtrack,
You said, "I also suggest you withdraw your blog on" solar that works" It is full of errors & assumptions that could lead many astray"

I've asked you twice now for an example of any "error" and you still can't post one, so I can only assume you can't find any and you just had to post to make yourself feel better, after all it is called "Solar that works" because it does work.

Maîneÿ . . .

Allan,

...If you want to realise a panel output closer to your rated 200 watts you will need to spring for a MPPT controller....


But that will hardly improve the situation on a warm/hot November day in Busselton.
No MPPT in the world can make up for temperature induced PV losses.

Best regards, Peter

Allan,
your numbers; ...........12 amps multiplied by 14.3 volts equals 171.6 watts
are not relevant, reason being the battery voltage (14.3v) is taken at the battery, not the solar panel, if I had taken it at the fridge it would be lower again, and if I took it at the solar panel it would be much higher.

The 'Voltage gauge' is connected direct to AGM battery system
The 'Ampere gauge' is connected between battery and solar regulator

To ascertain the Wattage of a solar system, you have to measure Amps and Voltage at Solar panel.

Maîneÿ . . .

"your numbers; ...........12 amps multiplied by 14.3 volts equals 171.6 watts
are not relevant, reason being the battery voltage (14.3v) is taken at the battery, not the solar panel, if I had taken it at the fridge it would be lower again, and if I took it at the solar panel it would be much higher"


Hi mainy
why don't you do just that, measure @ the input to reg or @ panel terminals


Surprise ,you will get something like 14,5<14.8v.with a battery voltage of 14.3v
14.8v x 12 amps =177 watts.

I still think you should stay away from posting on electrical matters.
From your above statement ,you do have problems even understanding basics such as voltage drop ie voltage lower @ fridge ,why? because of voltage drop
Ohm's law is a basic formula ,if you cannot understand how it works or it's implications you have no hope of sensible discussion on such matters

oldtrack,
If you read the thread again you will see I have stated any electrical specs for Solar systems should only be taken at the solar panel

Remember; I asked ONLY for photo's - not any discussion at all

Maîneÿ . . .

Mainey, you are quite correct.

It is not your Solar panels that are inefficient.

It is your Steca regulator that is only about 70 - 80% efficient.

200Watts in. 177 watts out.

Boo Boo k,
a newcomer to the thread with now over 2,1OO views in just a few days, so you believe the Steca LCD screen will display *12 Amps* from a 203 Watt solar system, when it's only 70% efficient ??

No wonder I've asked for a photo and NOT hypothetical maths, you also have no idea at all

Maîneÿ . . .

Honestly Painey.

You are going from clueless to childish now.

It really is pointless discussing these matters with you. I wouldn't bother but it your posts could be dangerous to *other* people who know little about electrical matters on these forums, and they need to be debunked.

Is that why you would not answer the question I've asked you ?

Because your answer will show how totally clueless you are

Just for your benefit I will repeat the question for you:

"so you believe the Steca LCD screen will display *12 Amps* from a 203 Watt solar system, when it's only 70% efficient ?? "

Maîneÿ . . .

Hi Mainey
""so you believe the Steca LCD screen will display *12 Amps* from a 203 Watt solar system, when it's only 70% efficient ?? "

YES , YES & 1000 times YES

oldtrack,

Ok, so please name any combination or single 203 Watt solar panel/s that is rated by the manufacturer above 12 Amps by aproximately an extra 30% (~15.5 Amps) as your saying above

Maîneÿ . . .

Mainey, you can not focus only on amps and ignore voltages and power.

A resistor can have 12amps in and 12 amps out. In fact it has to. Amps don't disappear into thin air and measuring the amps in and amps out shows only one thing. How little you know. This is one of the cornerstones of electrical theory and you obviously have not done that.

To repeat. You are right. Your panels are outputting as per their spec. However your Steca is only 70% efficient. Not theoretical maths, you get that straight from your photo ( if you have a clue what you are talking about).

I can not account for the fact that you are clueless on this subject. Photo or not.

Boobook,
You now say: "You are right. Your panels are outputting as per their spec. However your Steca is only 70% efficient. Not theoretical maths, you get that straight from your photo "

Please explain why you believe the "Steca is only 70% efficient" ?

Maîneÿ . . .

Because it looses 30 plus Watts to heat. It is the loss point in your system. Not the panels, not the battery, not air and not the fairy princess.

BTW don't come back with that "but it doesn't lose amps" nonsense. YOU CAN"T LOSE AMPS - PERIOD, no matter what you incorrectly think.

Maîneÿ,

solar panels are rated first and foremost in Watts and not amps.

Your 204W rated panels only produce around 170 Watts in real life which isn't better or worse than many other panels.

And other panels aren't going to perform better or worse than your panels.

You've come across some (true) statements that PV panels in real life will deliver less than their rated output.
If you wanted to see this statement reflected in the reading of your battery ammeter, all you'd have to do is connect your panels to a MPPT and watch how low your amps get on a hot day.
Not using a MPPT effectively obscures this effect because a simple PWM or on/off regulator hardly ever gets maximum extractable current into the battery (particularly on cooler days) - you can't see the decline if you never reach peak.

Then somehow you thought you could use some photos to convince us that your panels are outputting 100% even in real life.

After you noticed that the drop in output power is not caused by a drop in output current but by a drop in the MPP voltage, you try to save the day by stating you never talked about power.... I'd say you blew it Maîneÿ.

Best regards, Peter

Hi Mainy
here are some basic formulae to work on
amps =volts /ohms
watts = amps x volts

volts is an electrical pressure/force
amps are the rate of current flow
watts are instantaneous power

Multiply instantaneous watts by time [say hrs ]& you get watt hrs

You cannot just use amps to claim a power rating, voltage has to be part of the calculation


Yes you are getting rated AMPS, BUT NOT RATED POWER

Peter,
My system registered *12 Amps* at the Steca regulator

Question: -> what % is my system registering in comparison to expected maximum as stated by the panels manufacturer ?
(is it 100% or is it 70%)

Their specs nominate; current at Pmax - Imp 12 Amp
The panels are rated at; 203 Watts

The answer to my question is all I'm interested in :)

Maîneÿ . . .

HI Mainy
I'll try another way to see if you can understand
Amps are not power. Watts IS the only way to rate power. Panels ARE rated in Watts
The POWER going into your battery [power output of panels ]& remember power is watts]
Volts @ battery [14.3] by amps [12] into battery.
P[power = volts x amps]
14.3v x12a=171 watts , the panels are not giving out 205watts.
Again do a simple thing, check the voltage @ the panels while under same conditions
It will not be 17v!!!!

Maîneÿ,

....Question: -> what % is my system registering in comparison to expected maximum as stated by the panels manufacturer ?
(is it 100% or is it 70%) .....


Answer: when you took this measurement on 21/11/2007 at 11:21 am @ -33.66/115.3 (near West Busselton) your panel wasn't facing the sun fully, and the cell temperature exceeded 25 degrees significantly.

Thus, the output was lower under these (real life conditions) than the specced value because the manufacturer follows standard test conditions at which the panels are tested/rated.

You cannot by any means negotiate the loss of output caused by the panel not fully facing the sun, and the output voltage dropping by 0.5% per degree cell temperature.
Note well, in order to observe this drop in voltage your panel's terminal voltage must not be clamped down to the battery voltage.
The only way to observe this is by using a MPPT.

To answer the second part of your question: your panel output was certainly lower than the specced value.
If you define specced value as 100%, then the output at the time of your measurement was less than 100%.

Note well, when comparing panels, we're comparing Watts, and not amps.
You can tweak the amps and volts made available to your panel's load, to whatever you feel like by electronic means, but not the specced (maximum) Watts.

I just noticed the possible key for you not understanding this properly:

.....Their specs nominate; current at Pmax - Imp 12 Amp
The panels are rated at; 203 Watts ......

At first sight this might read like 'if the current has reached 12 amps, my panel output is at maximum rated Watts'.

This assumption only holds true for a linear relationship between voltage and current.
Ohm's Law would be appliccable.

But solar cells are different.

The key to understanding PV output characteristics is to understand the non-linear relationship between voltage and current.
The output current can be almost constant while the output voltage varies with the load impedance.
That's why solar cells can be thought of a 'current source' rather than a 'voltage source'.

So if your panel voltage would be allowed to increase beyond the battery voltage while keeping the current constant, the output power of your solar panel increases while the amps (and power) through the battery stay constant.

The surplus of power in the above scenario would be dissipated as heat in the device wired in series with the panel and the battery.
A MPPT on the other hand won't dissipate this extra energy as heat, it'll convert much of it into useable amps.

Now, before I send you a cheque for tutorial fees, I call this the end of my contributions to this thread of yours.


Best regards, Peter

...invoice for tutorial fees that is....

Best regards, Peter

Peter,
so are your suggesting the 12 Amps showing on the LCD screen of the Steca solar regulator is not available from the solar panel ??

"Now, before I send you a cheque for tutorial fees, I call this the end of my contributions to this thread of yours" Peter I don't want YOUR cheque :)

Maîneÿ . . .

nah duhhh Maîneÿ....

your stubbornness costs me and others a lot of energy - basic courtesy would suggest another reply from you - but never mind.


Best, Peter

Peter,
I think it would have been much quicker to just answer the question I asked you with either an 'yes' or 'no' ?

Maybe the "nah duhhh Maîneÿ.... " is your way of saying, no, the 12 Amps showing on the LCD screen of the Steca solar regulator is not available from the solar panel ?

I don't believe it is "stubbornness" when someone asks a question and can't recieve a simple 'yes/no' reply

Maîneÿ . . .

Maîneÿ . . . posted:
Peter,
[1[I think it would have been much quicker to just answer the question I asked you with either an 'yes' or 'no' ?

[2]Maybe the "nah duhhh Maîneÿ.... " is your way of saying, no, the 12 Amps showing on the LCD screen of the Steca solar regulator is not available from the solar panel ?

[3[I don't believe it is "stubbornness" when someone asks a question and can't recieve a simple 'yes/no' reply


Hi Mainey
[1] You have had the simple answer many times IT IS NO YOUR PANELS ARE NOT PUTTING OUT THEIR RATED OUTPU T .
THEY ARE ONLY PUTTING OUT THEIR RATED AMPS
NOT THE SAME THING

[2] Yes they are putting out rated amps BUT not rated power ,
which is how they are sold, by power, watts.


[3] WHAT !!! THAT coming from you who simply refuses to accept a NO answer& then refuses to accept any explanation of how or why it is NO

YOU HAVE NOT & CANNOT DISPEL THE MYTH IT is NOT a MYTH .IT IS CORRECT

SIMPLE answers ARE for Simpletons , you certainly fit THAT category with your stubborness to accept facts put forward by those who know what they are talking about

But then again you do not understand BASIC electricity.
So it would be just as easy to try & explain to a 6year old
The sad thing about this thread is that many may believe you are correct because they cannot "sort the wheat from the chaff" in your posts & some of the replies.

oldtrack,
What *evidence* do you have access to, to be able to state:
" YOUR PANELS ARE NOT PUTTING OUT THEIR RATED OUTPU T ."

when you do state: "THEY ARE ONLY PUTTING OUT THEIR RATED AMPS" ?

Maîneÿ . . .

no

;-))

The only *verifiable fact* is the system is producing 12 Amps !

The numbers used in the equations on here are ALL “hypothetical”

I suggest this because firstly no-one can even agree between yourselves anyway as to what is correct and what is wrong.

Secondly they are not presented in any visual way, other than being printed on the back of solar panels, however even then they are not even believed by some of you.

Some have stated they know nothing about solar power, and they still argue about something which is not even relevant to my original post at all.

If some of you took the time to read it, you would see I clearly only wanted information as to the *12 Amps*
Nothing at all was asked about the Voltage or Watts as I don't need that information.


Now you can continue arguing like little children, or get back to the question I've asked, your choice as usual.

I only want the question I've asked answered, yes or no will be fine.

Maîneÿ . . .

NO

LOL - HELP, MAYDAY, MAYDAY, HELP.

Allan - I started reading the thread to help me understand this Solar thing - I have to say exactly what you have.

I guess all I have to know if I want to run my Waeco without a generator I need at least 200w of Solar facing the sun???? to supply my 2 x115amp hr Deep Cycles.

Tony,
No, you will get away with a smaller solar system than mine, as I run a fridge drawing more Amps than a Waeco.

Maîneÿ . . .

Oh no Phil, Mainey will collect all sorts of bits of data from that site and build a nuclear bomb with it! How could you have been so thoughtless? LOL

Hehehe I like being thoughtless. There were a few equations there that could put a stop to this debate - none of us would have a chance of understanding :-))

But the link had a nice simple definition and graph at the top.

Wrong Phil!!!!

17V is NOT the open circuit voltage.
It is the voltage at which the panel WILL produce it's maximum output, however, when connected to a battery with a simple regulator, it can not go there ever, it will always be the same (within about .5V) as the battery voltage (unless the battery is full and the regulator switches to float or equalizing charge, in which case the panle voltage will rise to 17V or more, but then the regulator will limit the voltage applied to battery to around 14.5V and very little current will flow.....so, the panel will not be supplying it's full output... and so it goes.

Good thread, eh?

hehehe......bugger!!!
I made an assumption there - thanks for correcting me. Open circuit voltage is more like 21V.

See you can't even agree among yourselves :)
did I mention 'children' some where ha ha


I've no need to understand *OPEN CIRCUIT VOLTAGE* as no-one can agree on the Voltage *number* anyway, if I took the photo 5 mins earlier the number would be different - maybe ?


The thread and the question I asked is ONLY relevant to the Amps produced by the solar system shown in the photo, nothing more than that.

Maîneÿ . . .

wow,
an intellegant thought and a question, thank you :-)


Solarex VLX & Sharp ND-L3EJEA

Image Could Not Be FoundMaîneÿ . . .

Just an addition Mainey.

To measure the energy used by the fridge one needs to monitoe the current and voltage over the 24 hours. Over this time the frigde cycles on and off and as it takes energy out of the battery the voltage drops. Now what I have done is to estimate (guess) the average voltage and current - one cannot do anything else in the absence of real data. But these may be good ball park figures.

Jeremy.

Jeremy,
and the relevance of your post is ???

is it somehow relevant to the original question I've asked about the 12 Amps ?

Maîneÿ . . .

Just answering your question about energy, previously posted.

Question asked:


How do you explain the 12.5 Volts ??

"Solar panel delivers say 375 WH per day ( 12.5 V x 5 A x 6 H ) thats it"


I seem to have put the answer in the wrong place - apologies.

Jeremy

Allan,
there's just one ( 1 ) reply to the question I've asked

Maîneÿ . . .

Mainey,

"Like Sand through the Hour Glass, so are the Days of Our Lives"

I wish you well,

Jim.

Thanks Jim,

Unfortunately "Days of our lives" lasted for many, many years :-)

I hope this thread is short lived and when I get a few replies that can give logical explanations to the *original* question it goes into cyberspace

Maîneÿ . . .

Yeah "The Daze of our Wives" went for a long time what about the Forsyte Saga" was a bit shorter.

Mainey,

You're not getting it.

Neither you, nor me, have any real understanding of electrcal principles.

The difference between us is that I know my limitations.

Hi All
now just to confuse Mainy & some others, not you Jeremy,
Here are a few calculations showing load volts @ battery versus POWER out put from solar panel
& Mainy have you tested the voltage @ the panels yet??
Because as iI said before it will about .25< .5 volts higher than your battery volts
Despite your refusal to accept it, POWER IS AMPS BY VOLTS
THE MAX POWER OUTPUT IS ONLY PRODUCED @ONE VOLTAGE APPROX !7V for most panels
NOw for the calcs remembering the panels are near constant current no matter what the battery voltage /load voltage

Batt volts11.6v X panel amps 12= 139 watts [68% of rated output]
bat volts 12.6 x panel amps12 = 151 watts [74% of rated output]
Bat voilts 15 x panel mpas 12 = !80 watts [88% of rated output
& if you did not have a reg the battery volts /load volts could rise to 17v
Then bat volts 17 X panel amps 12 = 204 WATTs MAX POWER & rated output [100% OUTPUT CAN ONLY OCCUR @ THAT POINT.]

The MYTH is NOT myth IT iS FACT


But all of this is wrong in your mind because your simply do not understand basic electricity

I would strongly recommend you accept the facts put to you that you are wrong , do not know what you are talking about & stop confusing others who have limited electrical knowledge.

oldtrack,
Sorry, if you read my original post you will see I asked for the answer in AMPS (current)

I'm comparing *12 Amps* with manufacturers current specifications

I'm not seeking to compare Watts (power)
Because I've NOT used a photo of Watts for comparison purposes

Maîneÿ . . .

Hi Mainy
And that is the problem ,YOU SIMPLY DO NOT KNOW WHAT YOU ARE TALKING ABOUT.

YOUR KNOWLEDGE OF BASIC ELECTRICITY IS ZERO.!!!!!!!!!
Yetyou are not prpared to listen to advise of qualified people in the trade
Perhaps you will answer this question WHAT ARE YOUR QUALIFICATION ????

YES,your panal s put out 12 amps,the max current specified
NO,they are not putting out their ratedpower
A simple question , when you buy a genny or inverter , how is it rated AMPS or WATTS ???? as you should now see you are buying WATTS = power

What does an electricity bill show you are buying ? WATTS = power
What are electric motors rated in ? WATTS = Power

What goes into your battery to charge ???? ,POWER= amps pushed by volts = power = watts.
IF you cannot understand these SIMPLE FACTS,you should refrain from ever posting on ANYTHING ELECTICAL

oldtrack,
You say;
"YES, your panal s put out 12 amps, the max *current* specified NO, they are not putting out their rated power"

So now I ask you, what is the their maximum *current* rating - if not 12 Amps ??

Please remember, I've asked for the maximum *current* available
So don't go and change the wording to give me Watts - again & again



You then say;
"What goes into your battery to charge ???? ,POWER= amps pushed by volts = power = watts"

CURRENT = Amps, charge a battery - please use the correct terminology

Maîneÿ . . .

Mainy
you still have not posted YOUR QUALIFICATIONS to debate elecrical matters your lack of understanding is appalling
PLEASE GO & BUY SOME BOOKS ON BASIC ELECTRICAL THEORY

Oldtrack123,
You know, sometimes having "Qualifications" can blind you to the simplicities of life.

Mainey did raise a simple statement about his solar system and quoted Amps.
Unfortunately he related them to the 70/80% efficiency often quoted about system wattage. But he is really only interested in Amps.

He does have some understanding of electrics but gets a little confused at times as maybe we all do! And he does have a well constructed solar system.

But to demand his "Qualifications" and bang-on about what goes into a battery to charge it is both confusing and irrelevant. Anyway, not only is it convention to measure and talk about battery charging in terms of Amps but in fact the chemical reaction within the battery is directly related to the current flow which I seem to recall is expressed in Amps.

Hi Allan

Mainey made a statement his panels are 100 % efficient.
THEY ARE NOT!!
For simplicity sake it is usual to say "I need to put so many amps into the battery to charge it"[actual should be referred to as Amphrs.
But you took ENERGY out of the battery in supply lights, stereo etc which use energy which in electrical terms are called WATTS & those devises are RATED in WATTS
That is their power consumption
You have to replace that energy with WATTS
Watts [power ]= volts by amps
Or are you saying all the laws the elecrical ratings etc are built are wrong
I hope not or that puts you in the same class as Mainey

Lets take power energy a little further.
When charging a battery it heats up ,why, because of the energy loss & the chemical process taking place
The chemical process itself needs energy to take place& again I REPEAT electical power is measuerd in watts It is using watts to charge
Watts = volts by amps Without volts you cannot have power
This seems to be the point that have some very confused.

Because of the changing voltages during charge & discharge means the WATTS used or the watts going into or out of battery are also changing,
So the amps were some where along the line used , because that is reasonably constant with a constant current power source [ solar panels]
Here is a liitle example that you & others may understand
Do you accept that a battery generates heat when it is being charged??

Do you accept that energy ,WATTS, are consumed by lights etc & it has to be replaced
Do you accept that heat represents energy [WATTS] being used??
Do you accept that watts is amps xvolts ??
Do you therefor accept that you have to replace the WATTS used
IF so then you must use both load volts & amps as shown on Maineys own meters
AMPS X volts = watts
Another example: If you accept that lamps etc use energy & part of that energy is converted to heat
What happens when due to a dead short in a circuit the load voltage falls to near zero,
What power showing as heat is used in that circuit & let's use Mainys 12v amps, because with a constant current power source it will only be a small encrease./
The answer is very little because the voltage is zero But the amps are still 12 power WATTS =amps X volts = 12 x0 = 0
Nowr little energy is expendedin the load
WHERE does that energy go .
It is expendd in the source itself ,the reason equipment burns out due to overload

Mainey has a nice set up ,it works,well but for reasons he & others do not understand
The manufacyuers of all power sources rate thier equipment in WATTS that is the only way it can be done
Mainey's 204W panels are only putting out part off their capacity
They are no where near 100% efficient
The fact that Mainy sticks to his statement that volts & watts mean nothingcontinues to show he has a complete lack of knowledge.
Perhaps I should say he has atiny bit of knowledge,
BUT as the saying goes "alittle knowledge can be dangerous' & it certainly is in this case. with his constant refusal to accept that without voltage in the equation amps mean nothingas far as power out put is concerned & THATiS WHAT WE ALL BUY POWER,WATTS.

Hi Allan

Mainey made a statement his panels are 100 % efficient.
THEY ARE NOT!!
For simplicity sake it is usual to say "I need to put so many amps into the battery to charge it"[actual should be referred to as Amphrs.
But you took ENERGY out of the battery in supply lights, stereo etc which use energy which in electrical terms are called WATTS & those devises are RATED in WATTS
That is their power consumption
You have to replace that energy with WATTS
Watts [power ]= volts by amps
Or are you saying all the laws the elecrical ratings etc are built are wrong
I hope not or that puts you in the same class as Mainey

Lets take power energy a little further.
When charging a battery it heats up ,why, because of the energy loss & the chemical process taking place
The chemical process itself needs energy to take place& again I REPEAT electical power is measuerd in watts It is using watts to charge
Watts = volts by amps Without volts you cannot have power
This seems to be the point that have some very confused.

Because of the changing voltages during charge & discharge means the WATTS used or the watts going into or out of battery are also changing,
So the amps were some where along the line used , because that is reasonably constant with a constant current power source [ solar panels]
Here is a liitle example that you & others may understand
Do you accept that a battery generates heat when it is being charged??

Do you accept that energy ,WATTS, are consumed by lights etc & it has to be replaced
Do you accept that heat represents energy [WATTS] being used??
Do you accept that watts is amps xvolts ??
Do you therefor accept that you have to replace the WATTS used
IF so then you must use both load volts & amps as shown on Maineys own meters
AMPS X volts = watts
Another example: If you accept that lamps etc use energy & part of that energy is converted to heat
What happens when due to a dead short in a circuit the load voltage falls to near zero,
What power showing as heat is used in that circuit & let's use Mainys 12v amps, because with a constant current power source it will only be a small encrease./
The answer is very little because the voltage is zero But the amps are still 12 power WATTS =amps X volts = 12 x0 = 0
Nowr little energy is expendedin the load
WHERE does that energy go .
It is expendd in the source itself ,the reason equipment burns out due to overload

Mainey has a nice set up ,it works,well but for reasons he & others do not understand
The manufacyuers of all power sources rate thier equipment in WATTS that is the only way it can be done
Mainey's 204W panels are only putting out part off their capacity
They are no where near 100% efficient
The fact that Mainy sticks to his statement that volts & watts mean nothingcontinues to show he has a complete lack of knowledge.
Perhaps I should say he has atiny bit of knowledge,
BUT as the saying goes "alittle knowledge can be dangerous' & it certainly is in this case. with his constant refusal to accept that without voltage in the equation amps mean nothingas far as power out put is concerned & THATiS WHAT WE ALL BUY POWER,WATTS.


Might add "there are none so blind as those who do not want to see ". this is very applicable on this thread
The simple answer to Mainy's question is he is wrong he has not & cannot shown that panels are any where near 100% efficient in power output exceptt if/ when the LOAD voltage is approx 17v
Relook @ the % figues above for differant state of charge in batterys

oldtrack,

If you truly believe, as you have stated, my solar system is "only putting out part off their capacity, they are no where near 100% efficient" please advise me how many Amps I should be able to achieve with 203 Watts of solar power

Obviously you must use the photo I've posted above for any relevant numbers.

Please use the photo I have placed here as a referance, do not go off on tangents and 'suggest' other numbers, please keep your reply only relevant to the numbers shown above.

The question is:
how many *Amps* should I be able to get from a 203 Watt solar system.

Maîneÿ . . .

Oldtrack,

Is that rambling discourse directed at me or at Mainey? I certainly don't need it and it sure as hell is not going to help Mainey.

It seems you and some others just don't get it. Mainey said that his panel is "delivering 12 Amps which is 100% of the manufacturer's claimed output" and it would appear that is so. He is making no claim about his panel's delivered Wattage but does refer to expressions published elsewhere about efficiencies that happen to be in regard to Wattage and I have already addressed that.

All Mainey is saying is that his system is capable of producing the manufacturer's Ipmax of 12 Amps and it would seem to be so. Is it really necessary to bludgeon Mainey with technical rhetoric that is quite irrelevant and just confuses him further.

Not aimed at you Allan. Mainly for Maineys' benefit.

Jeremy

Hi Allan
No not aimed @ you personally
Read Maineys heading. " Dispelling the myth about panel efficiency"

IT is about efficiency . IT is about panel energy out put[WATTS]
That is what you buy with any solar panel. its ability to put out watts
IF it does not or cannot put out those watts it is not giving full 100% output As far as technical rhetoric goes how else can it be explained???

The actual tecnical rhetoric is VERY SIMPLE basic electrical formula & in many caes explained by example

IT is Mainey with his stubbornness to accept FACTS that is creating the confusion
I might add & I think Jeremy would agree that others have posted some slightly incorrect info or beliefs on this thread. sometimes in attempts to sopport his crazy idea in other cases opposing ihisRAZY idea. but they where relatively minor compared to to the ideas mainy puts up & with NO knowledge of the subjct [NOT qualified in any way]

Fact of life:

1. People like large - more watts , more current etc

2. Manufacturers oblige by specifying numbers with devices with more watts more amps etc. But they pull the wool over many peoples eyes.

Power is volts x amps.

They may use peak volts x peak current and you think you are getting average power (that's what matters) so you wonder why you will get less performance for the device.

They use big meaningless words like RMS power very simply because the sales department heads have not established the relative positions of their arses and elbows. And they pander to the fact that little knowledge is a dangerous thing (like my 4WD knowledge).

Who would sell more solar cells of the same area:

1. Company A : Advertises the panel at 200W
2. Company B: Advertises the same panel at 150W.

Jeremy

Allan,
Nope, I was not aware of Collyn Rivers stating that, I think you will find the "information" has been added to so many times now it is now probably no longer possible to be claimed as his information any more.

Does Collyn actually say that in any of his books ??

Maîneÿ . . .

Mainey,

I cannot confirm what Collyn Rivers says in his books as I have not read them, but he uses the 70% expression in this article here on ExplorOz under the heading "What About Watts". I doubt that it was his original expression but almost certainly came from a more authoritative source and is stated in many places but hopefully only in the context of Wattage and not Amperage.

I am not a solar power *USER* as such but I feel that I can substantiate that your system is producing 12 Amps by the evidence of your own photo .

Hi
Simple enough
IGNORE EVERY THING MAINEY SAYS ON ELECTRICAL SUBJECTS
HE HAS NOT GOT A CLUE

Mainey does not even understand what an electric apprentice would know in the first 6months of his apprenticeship YET he continues to carry on with his ridiculous theories

From A qualified lecty in many fields, as I assume Jeremy is from his posts

Well, Leave_enough_space, this solar thing can be confusing and made more so by those who throw complex expressions around to impress. But it's not all that hard if you get some good advice. One that can be relied upon for good practical advice is the Collyn Rivers book. Look here.

There are other sources of information free on the web but Collyn Rivers is a respected author on this subject and considering what you will invest in your solar set-up, the cost of the book may be well worthwhile.

Leave_enough_space,

If your confused how do you think some posters feel as they attempt to answer a very simple question with failed their maths, so much so that they can't even substantiate the numbers themselves as they continue to contradict each other in the process..

How many times do I have to stipulate I only want the question answered, not start a war.

the question was;
"Are there any other solar power *USERS* that can substantiate *either* side?
Using only photos as reference, *NOT* solar hypothetical or numerical equations"
Makes me wonder if some can even read at times as the grammar and spelling are horrific.

Yes, Collyn Rivers was a very respected member of this forum
L_E_S, maybe you should ask the question 'why did he leave' ?

Maîneÿ . . .

Yes, Collyn Rivers was a very respected member of this forum
'why did he leave' ?

I suspect because of threads like this one.

Lex,
I won't be drawn into arguments as to why he 'left'

BUT .....
I can assure you that the information on the page is NOT and I repeat NOT fully attributable to Collyn, he has not 'touched it' for some years now.

I can say in all honesty information has definately been added to Collyn's original information and should not be attributed as being Collyns information at all.

Maîneÿ . . .

Collyn's departure was pretty much as I recall it.

See it here

Back in the days when I was Jimbo.

Wow Jim, I had no idea that Collyn was once a member here. How dreadful that he should feel so set upon as to depart. And what a loss to the Forum.

Whilst reading the thread you instanced I noticed yet again in the archived threads how many Member names that no longer appear in current threads. There are so many who have come-and-gone. Disillusioned perhaps?

Oh, and I really liked his by-line :

"The problem is not so much what people don't know - it's what they think they know that simply isn't true."

With acknowledgement and respect Collyn.

Allan,

I've been around here since 2003 and have seen a lot come and go. I don't think it's disillusionment in the main; just changing interests and needs.

In Collyn's case, I suppose yes, he did become disillusioned by the constant barrages. After all, here was a chap who was able to sell his information and expertise in book form elsewhere, yet offered free advice and help on this forum. And what did he get in return (from a minority element I stress)? Mockery and ridicule. Any wonder he took his bat and ball and went home.

Regards,

Jim.

Please do not be discouraged. Solar is really very convenient and very very reliable, sought of free energy. It's just that it creates arguments every now and then.

Jeremy

The article mentioned and stated to be by Collyn Rivers was last updated on 29 March 2010.

Obviously NOT by Collyn Rivers, because Collyn has been gone for over four (4) years now.

For the article to be claimed to be attributable to Collyn is a legal nightmare, because who knows what’s been replaced or added or changed in the last four years and what is fact and what is complete fantasy or fiction ?

As stated above, buy Collyn's books, get the facts on things electrical, because you can clearly see from this thread I've instigated not too many people can agree on anything about solar power :-)


If you get to the end and read the last few posts you will see my own thoughts are vindicated by someone who I do respect, even though I do cause him to go off the deep end at times :-)

Maîneÿ . . .

if you're bored check out how many other forums have banned the troll.
lack of knowledge isn't a problem if you're prepared to admit that lack and then seek to learn. not everything you see or hear on the internet is correct.
if it looks like a duck, sounds like a duck, quacks like a duck there's a fair chance it's a duck.
substitute 'troll' for duck ;)

Allan,
try these two links for a start;

so with the reduced voltage we can only use about 70 - 80% of the rated wattage.

modules produce about 70% of that apparently claimed


Maîneÿ . . .

Allan,
here is another one

You lost 35 watts - but you paid for 120.

( Kyocera 120 Watt panel )
rated @ 7.1 Amps @ 16.9 Volts
7.1 Amps X 16.9 Volts = 120 Watts

Maîneÿ . . .

Mainey, I can see now where the 70% efficiency statements come from and why you take exception to them. But in each case they are referring to losses in Wattage not current or Amps.

#1 "The rated current is available, but we are limited to no more than about 15volts. Watts=Volts x Amps, so with the reduced voltage we can only use about 70 - 80% of the rated wattage."

#2. "What About Watts?
Solar modules only produce their claimed output under 'Standard Operating Conditions'. These have little resemblance to user reality. In a typical small 12/24-volt system most modules produce about 70% of that apparently claimed."

#3. "You lost 35 watts - but you paid for 120"

In each of these the reference is to Watts NOT Amps.

Mostly because of the fact that the Wattage rating is determined at the system Operating voltage (Vpmax) of about 17 volts but the battery is holding the system voltage down to around 14 volts the system cannot attain its maximum rated power unless an MPPT controller is employed to match these two voltages and utilise the 17 volts.

It is possible however for a system without an MPPT controller to attain the maximum rated Amps as you have clearly demonstrated.

Therefore, I believe that I can substantiate your claim that your system is producing 12.0 Amps, 100% of it's rated current, but forgive me if I cannot provide photos to support this as I do not have a solar system to photograph.

Furthermore, I do believe that others here who understand solar will agree with me about the above and I do hope that you do.

Regards,

Hello Mainey,

I think Iv'e cracked it !

I read your references and I'll quote from one reference

Quote :

Why 120 Watts does NOT equal 120 watts

Where did my Watts go?

So what happens when you hook up this 120 watt panel to your battery? Unfortunately, what happens is not 120 watts.

Your panel puts out 7.1 amps. Your battery is setting at 12 volts under charge: 7.1 amps times 12 volts = 85 watts. You lost 35 watts - but you paid for 120. That 35 watts is not going anywhere, it just is not being produced because there is a poor match between the panel and the battery. With a very low battery, say 10.5 volts, it's even worse - you could be losing as much as 35% (10.5 volts x 7.1 amps = 75 watts. You lost 45 watts.

End Quote

Response:

Where did my Watts go?

Answer to them : You did not have any in the first place!!

The 120W stipulated is a maximum power that the solar panel can convert from light to electrical energy. One does not pay for the 120W but what you pay for is the manufacturers promise that the cell can deliver that number of watts how much is extracted is up to you.

Remember that the cells are a constant current source and if we assume that it is in bright sunlight and receiving its 900W per square metre then the power converted is the current (example was 4.5A) x Battery voltage. This is the power that is being converted and is charging the battery. When the battery volts are low the power is low.

If you lost power then something would get hot (losses) but the main loss is in the internal resistance of the cell itself. Remember the short circuit current is slightly higher than the load current, that current difference - about 200mA - causes power (I**2 x Rint)) to dissipated in the cells themselves - this is the main loss - not the difference from 120W.

Here is something that grates with me:

... there is a poor match between the panel and the battery ...

Poor match ? Ask the writer to tell us about the best match and then tell us the answer !!.

Matching for max power is a very special thing and there are many conflicting conditions here that will not allow it and this is another reason one will not get what the manufacturer promises.

What do you recon - write a blog about this stuff?

Jeremy.

From the other reference:

Fridge (compressor type) running about 1/3 of the time: 3.6 Amps x 7 hrs = 25 Amphours
Camp lights : 1.7 Amps x 3 hours = 5 Amphours
Laptop: 4Amps x 1 hour = 4 Amphours
Charging camera, torches etc: 1 Amp x 1 hour = 1 Amphour
Hf radio (12A peak, 2A avg): 2 Amps x 0.25 hours = 0.5 Amphours
Uhf radio: 1 Amp x 0.5 hours = 0.5 Amphours
Am/fm/cd: 1 Amp x 0.5 hours = 0.5 Amphours

Would you question these numbers ?

You listen to the CD / Radio for 30 minutes only ?
Keep the lights going for only 3 hours only ?

Does everyone have really early nights?

Guys you miss the point I was making

Can you agree my solar system is rated @ 12 Amps - by the manufacturer
Can you agree my solar system is rated @ 203 Watts - by the manufacturer

My system does register *12 Amps* at the solar panels (shown in photo)

Where have I lost any Amps ?

How can that be explained when we are told to expect a 30% loss in Watts and the battery is only 14.3 Volts ??

Maîneÿ . . .

(I said I would never respond to Mainey again but I'm feeling masochistic.)

From your first post:-
"solar output available from my system, which is rated at 203 Watts. "

Your current is 12 amps. Agreed.


If your battery voltage is 16.91V then your output is 203 watts as specified.
But your meter shows your voltage is 14.3V.
Therefore your output is 171.6 Watts. Approx 85% of the rated 203 Watts.
(Assuming the regulator is in bulk charge mode and neglecting losses in the regulator.)

Mainey I'm sick of seeing the same meaningless photo of your solar panel producing 12Amps. If you had any knowledge of how a PWM shunt controller worked you would know that display bears little relationship to the charge current.

As I have said before. Show us a photo of the display of the charging current and voltage. That's the one that matters.

Wow, what a thread!!!

But you know, you are all right!!!

Its a bit like how an engine is rated at say 205kw, but put it on a dyno and you can only measure 150kw. The difference is drivetrain losses etc... but the engine IS making 205kw at the flywheel.

On solar you get say 205watts at the panel, but only get say 150watts to the battery. The difference here is the losses due to panel voltage and battery voltage while current is fixed. But the panel IS making 205 watts :)

So, its really all about what you can make and what you can use - they are not the same.

But boys, surely this could have been handled better... I have seen my cub troop behave in a more appropriate manner :(

Cheers

Captain

Mainey,

12 Amps rated, Agreed.
203 Watts rated, Agreed
12 Amps in photo, Agreed

You haven't "lost any Amps"

30% or 20% loss in Watts is a typical statement applied to solar panels.
But remember, it applies to the rated panel Wattage, repeat Wattage.

In your case your meters show 12 Amps and 14.3 Volts flowing to the battery.
Now that is 12 x 14.3 = 171.6 Watts produced by your system. Agreed?

Your panels are rated at 203 Watts so 171.6 / 203 = 84% of what might be achieved under ideal conditions and using an MPPT controller. Not bad actually.

But importantly, your panels ARE producing the manufacturer's rated Amps.
Yep, 100% of them! You have not lost any Amps.

Lex,

Did you make any allowance for the fridge running off the battery :-)

Did you have any reason to suspect why only 5 Amps is shown on the Ampere meter going to the battery ?

Sorry Lex it was an old photo

Maîneÿ . . .

This post has been read by the moderation team and has been moderated due to a breach of The Advertising/Self-Promotion Rule .

Forum Moderation Team

Mainey
I couldn't care less about the "5 amps on the meter going to the battery".

I don't know how your system is wired or where the ammeter is in the circuit.

I don't care if the fridge is running.

Your regulator shows the panel is outputing 12 amps. I believe that is the PWM shunt current and is effectively the short circuit current of the panel which has no relationship to what is going to the battery. Show us a picture of the regulator display showing charging current and the battery voltage. Then maybe we can have a meaningful discussion about the efficiency or otherwise of your system.

I feel sorry for the people on this forum who don't understand solar and come here for information. Most of this post is irrelevant crap, as is the content of most posts here about solar.

My suggestion is if you want to know about solar, don't ask it here. Some members seem to go out of their way to confuse others.

Go and read Collyn Rivers books or some other reliable reference.
He doesn't have trolls in his books.

Lex,
would you actually say I've not lost any Amps ??
( considering it was only a 203 Watt solar system that produced the 12 Amps )

Maîneÿ . . .

Hi Captain, I sure would expect a Cub troop to behave better!

The operation of a solar system can perhaps be described as somewhat like a vehicle engine. There is a point of engine revs where it will produce maximum torque and the gears are used to match that to the required road speed.

With a solar panel, there is a point known a the Maximum Power Point which is a panel voltage of about 17 volts where it will produce its maximum power. Then, instead of a gearbox we employ a MPPT (Maximum Power Point Tracking) controller which is a DC to DC converter to convert the 17 volts to about 14 volts suitable for charging the battery. In so doing we reduce the voltage but get a gain in current. We are now using essentially all the power (Watts) that the panel can produce.

The only power losses are a little in the conversion. We get almost all the power that the panel can produce. What we can make we can use.

Mainey
You ask.

"would you actually say I've not lost any Amps ?? "

About 6 followups back I said
"Your current is 12 amps. Agreed. "

You're now displaying that not only do you not understand how solar panels and regulators work and you have confused knowledge of anything electrical, you also cannot read plain english.

And don't come the usual trick of re-asking the question. I'm not interested in your childish games.
*********************
Mainey said
"Please don't agree so readily, we will never see 3,OOO views now,"

Sounds like an admission that this whole post is a troll.

Can you give me a good reason why I shouldn't notify the moderators?

Mainey, it doesn't matter about only 5 Amps going to the battery and the other 7 Amps going to the fridge. The Steca shows 12 Amps being produced by the system and that's all that is important to your case.

Don't push the 3,000 views or you may get accused of trolling!

Lex,

Don't have a hissy fit

Yes, I actually want you to notify the moderators and have the entire thread removed, deleted and made totally nonexistant.

It has now served it's purpose and will save me the time and trouble, so thank you in advance :-)

Maîneÿ . . .

Hi Alan,

My response was for Maineys' benefit.

Hope I put this response in the right place!!

Rgds,

Jeremy.

Re: Did you make any allowance for the fridge running off the battery :-)

LoL

I had a wind generator, once, that I got the distinct impression that the load was driving the generator!!

Hi Alan B

"...the only power losses are a little in the conversion. We get almost all the power that the panel can produce. What we can make we can use..."

Yeah I know, but it was the closest analogy I could think off that may ring a bell. If only we could have a 17v battery then everything would be fine - well maybe not... I was originally giving the benefit of the doubt but now I suspect a troll :(

Cheers

Captain

Aye, Aye, Cap'n, fair enough.

A troll? Well maybe. Methinks Mainey just enjoys a joust.....has nothing better to do....... and accordingly never agrees to the clear conclusion as it would end the fun. The thing is..... we all fall for it whilst Mainey rubs his hands in glee! We are the fools, not Mainey.

But it is obvious that when it comes to electrical matters Mainey is a pretty good fisherman. LOL Then again, he has assembled a solar power system that works pretty well............ and that's more than I have done!

Mike,
will you please tell us all here what brand of solar panel you recently bought that you are so unhappy with because it was not working for you as you expected, now you would want to warn others what brand not to buy - wouldn't you ??

Maîneÿ . . .