HELP!!!!

[gnoeld]

I have 3 solar panels
When I connect two of the panels in a series I get a certain reading from my MPPT CC
When I add a third panel in Parallel it cuts my readings in half
I thought I understood this but now I am very confused
Please help
Thanks

 

[John Frum]

What voltage do you get from the third panel by itself?

 

[sunshine_eggo]

If they are the same voltage, you can't parallel one panel with two in series.

EDIT

 

[rmaddy]

With 3 panels, assuming they are the same, they either all need to be in series or all in parallel. The choice largely depends on the specs of the panels and the SCC.

P.S. Please use a more descriptive title for your question.

 

[gnoeld]

Thanks everyone
I just learned something new

 

[MisterSandals]

With 3 panels they either all need to be in series or all in parallel.

You can't parallel one panel with two in series

Not necessarily true, but it depends on the panels. If all 3 panels the same, then yes.

But no, if (for example):
With 2x 100W panels and a 200W panel, one could parallel connect the 2x 100W panels to get the amps close to the 200W panel (some assumptions being made) and then series connect the pair with the 200W panel.

 

[rmaddy]

If all 3 panels the same, then yes.

I was thinking that when I replied. I edited my answer to make that explicit.

 

[sunshine_eggo]

Thanks everyone
I just learned something new

I also edited for clarity.

The deeper lesson is that two sources in parallel will be at the same voltage (generally speaking).

Your 2S panels were forced to drop to the Voc of the single panel.

Parallel strings of panels must have very similar series Vmp-Voc ranges.

 

[Bobert]

I accidentally put 2 of the same gender mc4 connectors on a extension wire I made. That will make your voltage confusing.

 

[gnoeld]

Thanks so much for your input
It makes sense that the panels would drop to the single one. I don't understand it but it kinda makes sense however, a great learning experience

 

[sunshine_eggo]

http://plaza.obu.edu/corneliusk/ec/VnP.pdf

I accidentally put 2 of the same gender mc4 connectors on a extension wire I made. That will make your voltage confusing.

I'm glad I'm not the only one that does silly things. I'm still lamenting reversing the polarity on my Celestron telescope mount. The "pop" and the smell are still etched in memory like it was yesterday.

 

[tomdav]

http://plaza.obu.edu/corneliusk/ec/VnP.pdf

I'm glad I'm not the only one that does silly things. I'm still lamenting reversing the polarity on my Celestron telescope mount. The "pop" and the smell are still etched in memory like it was yesterday.

WTF, Did you really smelled it!!!
Upser login

 

[nax_gt]

WTF, Did you really smelled it!!!
Upser login

what's the big deal in it, I too did it