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Voltage drop when Solar panel connected (Read 8370 times)
electron
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Re: Voltage drop when Solar panel connected
Reply #4 - Apr 4th, 2011 at 9:05pm
 
I thought about the meter being configured that way and did a quick test on mine, and it reads volts OK because the 10A shunt inside shorts to COM (common) anyway.

So we are back to why it's dropping low like that.

I doubt both panels would fail at the same time.

One thing I can think of is that there's some sort of corrosion on one of your connections somewhere, so check / clean all connections.

I don't think it's a diode, they normally fail shorted but if you had some lightning lately maybe one blew open or went resistive? If it did open you wouldn't see 52V so this is probably not it.

You should find them in the little black box on the back of the solar panel. You would want to measure the shorted amps on a sunny day on the other side of the diode. But I would check the connections first since that's probably easier.
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electron
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Re: Voltage drop when Solar panel connected
Reply #3 - Apr 3rd, 2011 at 9:01pm
 
masonyahoo wrote on Apr 3rd, 2011 at 8:39pm:
As for the meter Hell knows! I dont understand electrics much, I have learnt everything from watching youtube Videos!
OK, you are doing really, really well then!

Using the meter is quite easy.

To measure volts you put the black on "COM" and the red in the "V ohms" socket. And it looked like you had the right setting but usually it's the DC "200V" setting for measuring a 24V panel.

To measure current, you put the red into the "10A" socket and leave the black in "COM".

WARNING: Always put the leads back right after you are done. It's easy to forget and then measure ACROSS a battery or something and you will SHORT IT OUT. Remember that a amps reading setup is like a direct wire, it's a short basically and something like a car battery can produce way more than 10A! There is NO FUSE on the 10A setting on most meters!

And of course, you measure amps in SERIES with whatever load you have etc... I think you know that because for a while you had amp meters set up in your older videos.

And where did all your analog amp / volt meters go? You should leave them in, they usually don't lose any power and can help you tell if things are working properly. You had a shunt at one point, that is really low loss.

Just for reference, a typical 12V solar panel will put out 20V with no load, "open voltage". So just double that for 24V etc...

You can figure out the shorted amps, and estimate what they should be with a simple formula.

160W panels at 24V would be 160 / 24 = 6.7A ( W / V = A )

It will be close to that depending on the sun that day, how hot the panels are and things like that, and only short it for a few seconds. I don't like to stress my panels.

I am assuming your panels are configured for 24V.

So after you do some new measurements, volts and amps, maybe we can figure out what is going on.

Those inverters have internal fuses, you might want to check them *** if *** it gets to that point.
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masonyahoo
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Re: Voltage drop when Solar panel connected
Reply #2 - Apr 3rd, 2011 at 8:39pm
 
Hi,
I know the inverter works as I have tested it with other power from other solar panels.
It is a 20-50 Volt grid tie. It was working fine until a few weeks ago when it just stopped?
As for the meter Hell knows! I dont understand electrics much, I have learnt everything from watching youtube Videos!
I know they have a dioded in them could that be the problem?
I tried to hook them to a small light and that even dropped the volts to zero?
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electron
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Re: Voltage drop when Solar panel connected
Reply #1 - Apr 3rd, 2011 at 7:59pm
 
Welcome to the forum!

Referring to your video....
https://www.youtube.com/watch?v=UlYsHufsDl4

For your two 160W panels, 320W at 24V should be about 13A. You need to back track to the panels and see where  the problem is.

You can short a panel out with your amp meter quickly to get the "Isc", shorted current reading, which should be spec'd on your panel's sticker. If you have a good meter you should be able to use the 10A setting for 1 or 2 seconds to quickly check the end of that cable.

If you put over 30V into these things (if it's a "14 to 28V" inverter) they won't do anything.

They will run on 24V from two 12V batteries so you can test it that way to see if it's really the inverter having problems. If the batteries are good for about 13A output then it should put out it's full power of around 240W.

But.... I watched your video again and I see that was a 600W inverter, but I can't tell if it is a 24V model or not, please let me know.

And, more importantly, I see that your black lead is stuck in the "10A" socket on the meter, it should be in the "COM" for voltage readings, and if you want to read amps, then it would be "10A" and COM, and so I don't what the heck you were reading!

I hope that saves you a lot of trouble trying to back track that problem!

So let us all know how it's working after fixing that that, and I hope you keep getting lower and lower power bills!

Also, don't forget that it's always easier to conserve than it is to generate. I'm not sure what you are running all the time to get a $500 power bill, but I bet there's a lot of things you can do to conserve more! Maybe I can make some suggestions.

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masonyahoo
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Voltage drop when Solar panel connected
Apr 3rd, 2011 at 7:13pm
 
Hi,
I have 2 165 watts 24 volt panels. With no load on them they make a easy 50 volts.
As soon as i connect them to and load such as my grid tie inverter, the load drops down to about 2 volts and wont power anything?
I know the inverter works as I have other panels and inverter to test it on.
Can someone tell me how or why?
I have a youtube post with a video search masonyahoo1. look at my latest 2 vidoes to see what i'm talking about.
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