Yes the - sign would be reversed polarity.
(Or reversed probes)
Growatt inverter grid tied stuck in stand by mode
- Thread starter frasere2
- Start date
(Or reversed probes)
I almost did not ask, because I was thinking an electrician would never do that. Reversed polarity is when the positive and negative PV wired get crossed.
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MajicDiver
Solar Enthusiast
Does your inverter show any faults? See the attached screenshots for an example of a fault I created by unplugging power meter on inverter with no PV and no battery.
With some faults it will throw a fault and then reset in a few seconds after the inverter trips and if you are not watching you’ll miss it. It’s possible I guess that on reverse polarity it could be shorting the PV to bypass the mppt and the PV would be at Isc and virtually zero volts I guess. Never seen what actually happens when polarity is reversed.
With some faults it will throw a fault and then reset in a few seconds after the inverter trips and if you are not watching you’ll miss it. It’s possible I guess that on reverse polarity it could be shorting the PV to bypass the mppt and the PV would be at Isc and virtually zero volts I guess. Never seen what actually happens when polarity is reversed.
Attachments
Verified this morning the multimeter is reading correctly on a car battery, and verified it is reading negative 530 volts on each of the strings this morning when plugging the probes into their corresponding + and - spot.
No faults on the inverter. I did have 1 fault saying there was problem with the off grid box after I did the firmware update the first time. I turned off the "Enable off-grid function" option and this fault went away.
And yes it is definitely showing me negative polarity at the connection block on the inverter. Then when I turn the DC switch to the On position volts show 000.
Oh boy. Those electricians messed up. Easy fix though. Swap them one pair at a time since I don't see the the wires are labeled.
Fingers crossed
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I had a set of panels delivered once with the + and - swapped, added one to an existing array and the array voltage dropped, which was when the issue was discovered. Now I check every panel with a meter for +/- before connecting.
MajicDiver
Solar Enthusiast
I use a “point” tip screwdriver and it works very good. After you do it a number of times your hand learns the motion and it’s easy. I’ve had to move mine several times to get space right as system grew, lots of practice.
That might actually be better since the wires at the inverter have the right color coding already
MajicDiver
Solar Enthusiast
Would be interested if you can put clamp meter on before swapping and see what current is at. It would confirm what others on this forum say about how reverse polarity protection works, shorts the input to keep it from getting to the mppt, which would explain why you have no fault.
Like this? I have the array disconnect turned on, but inverter disconnect off, so it’s reading -530 volts with the probes, but doesn’t show anything with the clamp? Or should inverter disconnect also be on?
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At Max voltage it'll show zero current and at zero voltage it'll show max current
ITS WORKINGGGGG
Reversed the wires going into the inverter and it’s up and running!!! I can’t thank you guys enough. Now if you’ll excuse me I have an angry phone call I have to make to some electricians hahah
Seriously though, this forum is amazing. Wish I could send you all a box of beer
Reversed the wires going into the inverter and it’s up and running!!! I can’t thank you guys enough. Now if you’ll excuse me I have an angry phone call I have to make to some electricians hahah
Seriously though, this forum is amazing. Wish I could send you all a box of beer
Let's go!!!!ITS WORKINGGGGG
Reversed the wires going into the inverter and it’s up and running!!! I can’t thank you guys enough. Now if you’ll excuse me I have an angry phone call I have to make to some electricians hahah
Seriously though, this forum is amazing. Wish I could send you all a box of beer
Great catch @BKY2003
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MajicDiver
Solar Enthusiast
You would need the inverter disconnect also closed
I am sure everyone of us was thinking the same thing. I was just stupid enough to ask. Every time it came up in my mind, I would think there's no way an electrician would not check that.
