Solar array amperage drop help please???

[rootytootie]

I just started the set-up about 3 months ago and I bought all the panels new so there is not much wear on these panels at all. So at least I can rule out that. Now astrayan what regulator are you talking about that I need to check? Are you talking about my charge controller? The charge controller goes to 13.3 volts then shuts off completely until the charge drops back down to 12.7, then it starts up again. I just did a test voltage on the hole set-up a couple hours ago with and without a load. Without the load I was getting 20.48 volts for the whole array. Then with the load of chargeing the batteries back on I was getting 14.1 volts charging, but still the amps were only around 13. I just want around my 20 amps that I paid for to get the 294 watts you said I should get. It was getting to late to test each one because the sun was dissappearing, but I did get to label each conduit for each panel. So I will now know which one I am testing when I go through each of them.

Also no offense to the other members question, but what is with the thread jacking here? On the other forums I joined between cars, computers, etc.. Thread jacking was not an appreciated thing to do. I know I sound like a arrogant a#$, but just stating the disrespect it is to do that to other's posts.

[astrayan]

I'm suffering from a significant egg-on-face moment, today. Last night, I was reading about how to test solar panels, and one expert mentioned that it's kind of difficult to disconnect each panel and test the current, when you are up on a hot roof, so he suggested putting a hat over each panel and listening to a 12V pump, or whatever device you can, to hear if the panel is working. I used a volt meter across a length of the solar wire, making a shunt. It read 26.3mV. I then progressed down the panel array and found that 5 out of 7 BP 80W panels were dead. All 10 Solarex are doing fine after 18 years. (I fixed one a few years back.)

So, what I learned yesterday, is that you can't test a panel using its short circuit current - which I knew anyway. I tried to use an ammeter in-circuit, but I was too lazy for most panels. 4 of the BP panels produced a healthy short circuit current, 1 produced nothing. Under load, the 4 BP panels can't make it up to battery voltage. I measured one (open circuit) at 18V, so it's clearly impaired.

Back to your problem, though. If the regulator/controller is switching between 13.3 and 12.7, it is suggests :

1- it could be under stress from being overloaded
2- excessive voltage drop between the regulator and the batteries, so the regulator thinks it's switching off at 15V.
3- it could be miscalibrated

However, all in all I suspect (1), since you shouldn't be using a 10A controller. You should only have 2 panels on it. See if it works properly with 2 panels. If it doesn't you may have killed it. By and large, you should never exceed current ratings, since things explode.

[P34CHY]

No animals were harmed in this post

Rooty.
as i stated in my first post, i am new to all this and i did not
know of any thread jacking protocol. please accept my apologies,
but it would have been a tad more polite to point out my mistake
in a more instructive way, and then you would have no fear of
being ignorant.

by the way Mike i connected the kyocera and photons at the solar
controller instead of at panel source (is this ok) as they would still
be in parallel.
anyhoooo, the set up is giving 27.9v to batteries at 17.5 amps
not too shabby at all.

thanks again.

[rootytootie]

Apology is accepted. I am not really mad or anything because the other members tried to still help me a great deal and are still trying to, even though you posted another kind of question and they helped you also. If everyone switched topics and just shifted all their help and attention to you and I got nothing out of it then that would have been disrespectful situation, but like I said that was not the case, so I was just stating out what i have seen and experienced on other forums when I first started posting on the web.

Astrayan I will try that also and just use the harbor freight or just 2 panels with the controller and see what reading I get and I will post them. I dont think I burned it out yet or hopefully did not. I know putting to much power to it would make it melt or explode I downloaded a video off youtube of a charge controller melting. I got it for free with the kit, so I did not care because I know i was going to need a new one. I am looking at the morningstar tristar mppt controller that is coming out in the next couple weeks, but now I just saw the video on midnite solar's charge controller coming out next year so I am stumped as to which one I should get, but I will post that topic in a new post later. Thanks again.

[P34CHY]

rooyt.

Hi rooty.
starting to find my way around and discovered how to start a new thread.
once again sorry for treading on any toes.

good luck over the weekend.

[rootytootie]

lol alrighty man. No problem at all. You got your problem fixed so good for you. I think I got mine fixed. I think I found the problem I isolated each panels today in the short winter sunlight hours we have here. I found out that you can no trust your solar panel company to have them wired correctly when it is delivered to your door. I found 2 panels that were wired on the wrong terminals inside the circuit box. When I got to those panels I was getting 150v 250v 110v I was like wtf is going on here. I thought my panels were broke and damaged. Then I looked over them again and used my meter and wired them the right way. Now every panel seperate is putting out 4 amps or more at 13.05 volts when hooked to the charge controller. I thought it should be 14, but I guess I am wrong. Or maybe that is my cheap charge controller. I di dnot hook them all up in parallel yet, But i will next sunny day to see if I get the right amount of added amps. And yes the harbor freight is a piece of crap. I was only getting 3.5 amps out of that with 12.9 volts and that is a 90 watt set-up. So next year I will probably replace them with 80 poly's. But I want to thank everyone on here for your time and effort to help me out on this and hopefully the problem is solved now for the amps being so low. Lets see when I wire them all up.

[Jason]

Hi rootytootie and p34chy,

I'm happy to see you got the problems solved

Don't hesitate to post any other questions you have!

[hay4man]

Mike,

I agree with you 100%. If you have an installation (such as yours) where all the modules are pointed in the same direction and there is little chance of modules becoming individually shaded, then blocking diodes will burn power and generally be useless.

Astrayan,

The reason why your solar cells don't go poofsky when connected to a battery in the dark is because the battery voltage is much lower than the open circuit voltage of the solar module in daylight.
Look at this plot:

http://zone.ni.com/cms/images/devzone/tut/image42508.jpg

Say your OCV in daylight is 20V, and your battery is 12V. At night, only a small amount of current will flow out of the battery. Now, if you connect this same solar module directly to a 24V battery, your solar cells would go poofsky, whether it was light or dark out.

The problem is that when you connect modules in parallel, all modules are forced to the same voltage. If one module's open circuit voltage drops below the forced voltage, that module becomes forward biased and it will sink power (unless you've installed a blocking diode). If you think that it is highly unlikely that this will happen, the blocking diodes will burn power unnecessarily.

[hay4man]

Rooty, when you say 12.9V/13.05V/4A/3.5A are you measuring battery voltage/current or module voltage/current? Are you measuring on the battery side of the charge controller or on the array side?

I can't tell if your charge controller is doing peak power tracking. I'm guessing it isn't if you are expecting a lot more power. It might be a good idea to invest in an MPPT charge controller if you want more power.

At least it's good to hear that all of your panels are putting out some power.

[rootytootie]

I typed all this out already and my firefox crashed I am pissed. Anyway what i did was disconnect all the panels from the distribution block. Then I labels all the panels in ABC format. Then I connected each panel solely and came into my house and measure the voltage with a multimeter before the charge controller and disconnect switch. I took the volt measurement with no load of charging the batteries so the disconnect switch was off. Then I turned the switch back on and took the voltage with a load on of charging the batteries. And I also have a dc amp meter wired in before the charge controller and with it charging the batteries of course because you need a load to get the amp reading. That is how I got my readings. And no I do not have a mppt controller so I am getting screwed with that. But that is anothering thing I dont know which mppt to get. I am looking at the new morningstar or I saw the new midnite solar classic coming out next year. I am confused with that.

[Mike90250]

But that is anothering thing I dont know which mppt to get. I am looking at the new morningstar or I saw the new midnite solar classic coming out next year. I am confused with that.

What sort of power do you need ? That would dictate which controller to get.
Morningstar SunSaver 15 Amp MPPT can manage up to 200 - 250w of panels, and is stocked now: http://store.solar-electric.com/mosumpsochco.html

more than 15A, and then you have in stock, the Xantrex XW-60 at 60A, an outback 80A, and in a December, the Morningstar 45 & 60A MPPT.

[rootytootie]

I am looking at the morningstar 60a mppt because it said it has 99% efficiency rate which is going to be highest on market. But did you see the midnite solar classic yet? This looks interesting. This is the video for it.

http://www.youtube.com/watch?v=iifz1DxeaDQ

[simply]

I propose that let the three devices work separately.

[astrayan]

Astrayan,

The reason why your solar cells don't go poofsky when connected to a battery in the dark is because the battery voltage is much lower than the open circuit voltage of the solar module in daylight.

I dunno how you can say that sentence with a straight face.

[hay4man]

You're telling me that I'm wrong, which is fine. It's OK for you to think that I'm wrong.

But I think that in order to contribute to this discussion, you should explain why I'm wrong based on the physics of a solar cell or maybe even anecdotal evidence.

If you want anecdotal evidence, you can connect a 48V battery directly to a solar module with an OCV of less than 24V, and let us know what happens.