Panel shows voltage on its own but 0 in series.
- Thread starter diWhy
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robbob2112
Doing more research, mosty harmless
So, your negative lead on the end of the diodes with the line and it should read some reasonably small value - then swap and put the positive lead there and the negative lead on the other end and it should read infinity
If you get a short in both directions you have a bad diode - because they are in parallel you would have to snip one or both loose to find the bad one.
This is with the panels face down or covered.
If you get a short in both directions you have a bad diode - because they are in parallel you would have to snip one or both loose to find the bad one.
This is with the panels face down or covered.
When I tested, the panel was not covered but every diode in both directions were solid short. Meaning, instead of any ohms reading, I was getting a beeping sound like when testing connectivity. I'll have to do it again this time covered with a towel or something heavy because it was an awkward position so I feel like I didn't do it right.
robbob2112
Doing more research, mosty harmless
With the panel covered or face down if you get a dead short in both directions you have at least one bad diode in each set.
The thing that is confusing is you read any voltage across it when not connected, if all diodes are failed short you should never get any voltage out of it.
Most meters if they have a continuity beep also do diode test - Is there maybe that symbol there on the meter face and you missed it?
Diode test will be a single beep if good
The thing that is confusing is you read any voltage across it when not connected, if all diodes are failed short you should never get any voltage out of it.
Most meters if they have a continuity beep also do diode test - Is there maybe that symbol there on the meter face and you missed it?
Diode test will be a single beep if good
Yes, the meter has continuity/resistance test and that's the setting I had it on. In fact, I tried two meters just to be sure since it's hard to reach.
All diodes, no matter the polarity resulted in a beep. I think one of then showed a small resistance.
All diodes, no matter the polarity resulted in a beep. I think one of then showed a small resistance.
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robbob2112
Doing more research, mosty harmless
A beep or a constant tone?
A beep means the diode is good - a constant tone means it is bad.
A beep means the diode is good - a constant tone means it is bad.
Then to me that sounds like a faulty MC4 connection or the polarity is cancelling out the voltage.
If there is no load/current flow then the bypass diodes are not operating any more than the panel on its own.
What is the voltage of the panel-in-question when one side is physically connected to another panel?
Recovering EE
Solar Enthusiast
Every PV panel I've worked with, has the + on the female connector, and - on the male connector, with the naming convention coming from the metal pin configuration, rather than the coupler body appearance.
It's all very trans... electrically male is physically female and negative. Electrically female is physically male and positive Recovering EE
Solar Enthusiast
Is it possible that one or more of the bypass or blocking diodes is installed backwards?
I guess it's possible since it was never used in a string before, it used to have a micro inverter on it.
robbob2112
Doing more research, mosty harmless
That picture looks correct where it shows all of the diodes.... the positive end of the string to the left and the negative to the right.... Which means the negative wire should be hooked up on the left and the positive wire on the right. Normal operation positive wire is higher potential so the diodes are cut off.... If there is shade or something preventing voltage from being generated the potential from the two panels on either side cause the current to flow across the diodes with a bit of lost voltage per set. You have 2 in each set to handle the current, I would assume they are 10amp diodes or so just from the look without the number on them.
robbob2112
Doing more research, mosty harmless
You can also try hooking the panel in without diodes and it should work fine, but any shade will kill all production. Might be a good test.
Buy new ones and swap them - I could read enough of the number to find the part
robbob2112
Doing more research, mosty harmless
When I say buy new ones, I mean the diodes
No problem, I'd like to accomplish both. If I could fix the two that aren't working, that would be a bonus.
new off grid
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did you check to confirm every single panel was good ?
the the only reason there's no voltage after you connect in serial is
at least 1 of the connector is bad, when 1 bad, the whole string is zero voltage
now, check one by one connector , you will find out which one soon
good luck
not worth checking if both are outputting voltage on their own it just means the connector isn't working there's really no other reason it can be.
You already checked polarity and others are having you do it more but it can't be that if the multimeter isn't faulty
anyway take a wire and stick it into the MC4 connector of both of the units and stick them together and then see if it works
Sorry, I'm not really following here. I checked every single panel and every single extension I made. I had to make a bunch of 2' extension cables.
I found nothing wrong with any of the extension cables and the string works, only not with this panel connected. Once this panel is connected on either end of the string, the string shows no voltage, completely open circuit.
yea so the MC4 connectors are not connecting
stick a wire into the MC4 connector
stick the other end of the wire into the other MC4 connector of the other solar panel
this ensures the connectors are now connecting
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