Got my 2nd 3K Growatt but I think PV is swapped

[merrillbalan]

I used DVM on new Growatt and put RED probe on PV+ and other to PV- but I was getting a - Value instead of Positive. I opened up my older Growatt and did the same put RED probe on PV+ and other to PV- but I was getting a Positive value on my first one. See video below. I actually opened the front cover and dont see any thiung thats swapped anywhere. I know I would get a fault if this two PV cables is swapped, I am wondering if I should swap the cables putting negative to the positive and negative cable to PV + on growatt side. Thanks in advance for your input.

https://photos.app.goo.gl/MDnmsteSLAsSBhmFA

 

[JWLV]

Why did you even think of measuring voltage on the PV input when there's nothing connected? What were you hoping to find out? Do you also measure the voltage of your TV remote or wireless mouse before putting in the battery? It makes no sense.

 

[merrillbalan]

I was using my own cables for PV and they are all the same color so I was just doing some continuity checks and figured why not check if I swapped pos and neg cables so I stumbled to this issue. negative value bothers me as its telling me something is swapped. dont you agree

 

[JWLV]

With nothing connected, you should be getting close to 0 volts. Your meter's margin of error could make that reading go in the negative direction. Doesn't really mean anything though.

 

[merrillbalan]

With nothing connected, you should be getting close to 0 volts. Your meter's margin of error could make that reading go in the negative direction. Doesn't really mean anything though.

You are right and it makes sense about meter's margin error. Thanks for your input man.

 

[LydMekk]

Btw. never trust the COLORS of the PV cables in your tech room. It is easy to swap them by mistake outside/roof.
ALWAYS measure the cables before connecting them to the inverter or there will be expensive smoke...
Also, mount a rotary disconnect switch on the wall by the inverter which is turned OFF before connecting the PV cables to it.

Sorry if this sounds very elementary but it seems you are fresh in this field