How can you find out which cable coming from a Solar Panel is + and -

 

My BIL will bring me 2 330W panels (he has laying around at his house) and he told  me the  MC4 connectors have been cut off. Why that is? No idea.

 

Is it like in the picture, left hand side is - and right is +

 

They might be marked inside the connector box, but the simple test would be to strip the cable ends put the panel in the sunshine and check with your multimeter.

 

7 minutes ago, Crossy said:

check with your multimeter.

Oke thx.

 

What is the difference in the + and the - when checking with a Multi Meter? ????

 

Edit: If wrong way round then no reading??

4 minutes ago, MJCM said:

Oke thx.

 

What is the difference in the + and the - when checking with a Multi Meter? ????

 

Make sure your test leads are in the right holes (Com is usually the black lead).

Set to DC volts.

 

If the meter reads a +ve value then the red lead of the meter is on the + lead of the panel.

If the meter reads a -ve value then the black lead of the meter is on the + lead of the panel.

 

Check by measuring a known source, like a 9V battery that has + and - marked.

 

Yes it works perfectly.

 

I tried it with a AAA battery

 

Red on + = 1.41

Black on + = -1.41

 

Thx a lot!