2000k system only puts out 500 watt why?

[inetdog]

This whole 34 volt thing really bugs me. Is this really normal behavior for solar panels to drop off 4 volt's with in the first year? Granted I can not get a accurate reading on my current but when Missouri Wind and Solar tested the panels all they could get on current was 5 amps at 33 volts no higher on any of the panels and they told me the panels are still working properly and within warranty limits. I mean I don't know jack about solar compared to you guys but it just doesn't seem right. I know they drop off but from my understanding it's over a 25 year span at a slow decline not rapid drops. I mean who's right the licens tech who came out spent two days going over everything and told me the panels and cc are bad or the unlicensed salesmen. My gut tells me to listen to the guy who went to school but then again he could of slept through class. 34vX5a=175w That a 75 watt drop during peak time.

It is not at all normal for the panel voltage to drop over time, especially not in the first few years (if we are talking about a crystalline silicon panel). As the panel degrades with time the current at the same light level will decrease. If the voltage drops it is more likely an indication that one or more cells in the panel have broken and shorted out internally.
Or, of course, that the average panel temperature has gone up considerably. Increased temperature can conceivably drop the output voltage by as much as 10% in a very hot climate with poor air circulation around the panel. But when the panel is cool first thing in the morning the voltage should be close to what it started off at when new.

[charles2,david000k]

It is not at all normal for the panel voltage to drop over time, especially not in the first few years (if we are talking about a crystalline silicon panel). As the panel degrades with time the current at the same light level will decrease. If the voltage drops it is more likely an indication that one or more cells in the panel have broken and shorted out internally.
Or, of course, that the average panel temperature has gone up considerably. Increased temperature can conceivably drop the output voltage by as much as 10% in a very hot climate with poor air circulation around the panel. But when the panel is cool first thing in the morning the voltage should be close to what it started off at when new.

See missouri Wind and solar told me the panel puts out more power as it warmed up or gets hotter and when the panel get cooler or colder it puts out less power. So they lied to me correct?

[sensij]

What kind of grounding is used in this system? PID could affect Voc, and these look like generic panels that may not be as resistant as some others.

[inetdog]

See missouri Wind and solar told me the panel puts out more power as it warmed up or gets hotter and when the panel get cooler or colder it puts out less power. So they lied to me correct?

Well, it was either deception or ignorance. Not sure which is worse.
The current goes up with temp at the same time the voltage goes down. But for the panels I have looked at the net power goes down with temperature because the voltage change is a larger percentage than the current change.

People keep proposing innovative ways of trying to cool the panels during use, but the added complexity seems to make all of he ways less desirable than you might think at first.

[lkruper]

See missouri Wind and solar told me the panel puts out more power as it warmed up or gets hotter and when the panel get cooler or colder it puts out less power. So they lied to me correct?

I have heard the opposite. That in cold temperatures one must be careful not to allow the panels to exceed the input of charge controllers because output rises at colder temperatures.

Is it possible that is what they were trying to describe?

[inetdog]

I have heard the opposite. That in cold temperatures one must be careful not to allow the panels to exceed the input of charge controllers because output rises at colder temperatures.

Is it possible that is what they were trying to describe?

The biggest risk is that the voltage rises above the maximum DC that the CC input can handle. That is much less likely to happen with an MPPT CC with a wide input voltage range.
The second, less credible risk is that the overall power will somehow overload the CC.
But most MPPT CCs will just adjust their operating point to take only the amount of power that they can safely handle. A PWM CC may still be OK because the available current has actually gone down.

[sensij]

If the voltage drops it is more likely an indication that one or more cells in the panel have broken and shorted out internally.

If it was just one or two panels, this would be easier to suspect. For the same voltage drop to have occurred in all of them seems like something more systematic.

[inetdog]

If it was just one or two panels, this would be easier to suspect. For the same voltage drop to have occurred in all of them seems like something more systematic.

If these were amorphous silicon (thin film) panels or other than silicon chemistry there might be a voltage variation with age.

[JoeBlow]

you could never get back out what you put in and you would have to position the light directly over the panel I thought of it because I seen panels tested on a video in a solar panel manufacturing plant but I don't know if they are using 500W, 1000W, or two 1000W bulbs in different light spectrums.

But if the lighting was powered by the city grid, any power would be gain. I think it would be an interesting experiment. I watched the battery climb to 13v before it was disconnected from that panel. This was only a few minute test. I think theres a significant amperage considering the light source.

[almac]

my 2c charles

when i started my solar setup with alot of wonderful help from members here, thanks guys. got what i needed to know about batteries from sunking and bala and others, plus plenty of knowledgeable advice on everything solar all for free. what i did find out for myself is that some products are rubbish, particularly some charge controllers. and price doesnt indicate good design. my 1st CC was marketed as a MPPT cost $270 and did not put out enough current to charge my batteries. this CC was a setback. i spent money on petrol generators and dc power supplies to charge my batteries because the CC was rubbish. me not knowing that my panels were more than adequate in producing current did not suspect the CC. tried a replacement CC same model no improvement. then got a refund. then bought 2 very cheap PWM CCs at $40 each off ebay , they worked great, didnt need the gen anymore now have more power than i can use.

[jflorey2]

See missouri Wind and solar told me the panel puts out more power as it warmed up or gets hotter and when the panel get cooler or colder it puts out less power. So they lied to me correct?

Voltage drops significantly as temperature rises. Current rises _slightly_ as temperature rises. Overall power goes down.

[charles2,david000k]

If it was just one or two panels, this would be easier to suspect. For the same voltage drop to have occurred in all of them seems like something more systematic.

That is why I hired a licensed professional to check the system.
I fully understand that! This is my big problem with the merchant. I started off with 8 panels and are now down to 7 with the rest following the same pattern as the first. volts and current drop the first panel dropped to 25 volts before they had me cut into the junction box and voided warranty just to look at some diodes.

Grounding Is a 30ft bare braided 4 awg wire hooked directly to each panel then run to it's own grounding rod. I actually got the wire from the power company during a past ice storm. When the power company comes through during a ice storm they don't do clean up at all most the time they just leave their waste behind and I went out and asked for what they were going to leave so all and all I got a bunch of stuff nothing really cool though like a transformer just wire and a couple of poles and what I think might be a good transformer fuse. But my ground wire is rated for pole to home service drop which here is 220V @200 amp I think. the wire is 7 or 8 aluminum strands of 12 awg wire braided around a peace of 12 awg stainless steel wire. just went and checked to be double sure the ground wire is 1/4inch thick.

[charles2,david000k]

I have heard the opposite. That in cold temperatures one must be careful not to allow the panels to exceed the input of charge controllers because output rises at colder temperatures.

Is it possible that is what they were trying to describe?

hot equals less power. cold equals more power from what I am picking up from every one here. But Missouri Wind and Solar said the opisat. They said the cold drains the panels causing them to put out less power like a battery and hot equals more power like warming up a gas motor. I have a audio recording but the audio is to soft compared to background noise some one would have to clean it up.

[LETitROLL]

That is why I hired a licensed professional to check the system.
I fully understand that! This is my big problem with the merchant. I started off with 8 panels and are now down to 7 with the rest following the same pattern as the first. volts and current drop the first panel dropped to 25 volts before they had me cut into the junction box and voided warranty just to look at some diodes.

Somehow we just need to simplify this and get down the the basic fact of whether your panel(s) are actually defective in some way and losing efficiency that rapidly (not likely, but possible), or something else is going on. Have you (lately) unhooked the connectors right at a panel and taken a voltage reading straight from a single panel (no extra wiring, just the factory pigtail) from a meter that is trusted, and best if early on cool sunny day. There are so many things that can make them vary, including time of year, moisture in cable(s) or connections, or degredation of connections, just eliminate all that and take multiple readings over a day or 2 directly from one or more panels and I think you will get to a final answer quicker.

[charles2,david000k]

But if the lighting was powered by the city grid, any power would be gain. I think it would be an interesting experiment. I watched the battery climb to 13v before it was disconnected from that panel. This was only a few minute test. I think theres a significant amperage considering the light source.

I think your talking about getting light from a street light pole that might work but not for me. Here if you want a street light you have to pay for it. All the power company does is come out and hang it up on the pole and hook it into the grid then they charge you $17 a month added to your bill for the power you pull.