A Forum run by Enthusiasts of MidNite Solar

Charge Controllers and Clippers => The "Classic" charge controller => Topic started by: suntex on May 11, 2013, 04:48:28 PM

Title: Problem or not with Midnite 150
Post by: suntex on May 11, 2013, 04:48:28 PM
I have 12 Sharp 187 watt panels wanting to do 3 strings, 4 panels
in series....the problem is 2 panels are mono-crystalline and 10
are poly-crystalline....The  mono-crystalline panels have no labels
on them so I checked to see what the voltage was on them, I read
about 1 volt more than the  poly-crystalline panels.
I looked online for specs but couldnt find any....
Would this work on a Midnite 150 or not...
Title: Re: Problem or not with Midnite 150
Post by: suntex on May 11, 2013, 04:54:25 PM
Some pics of setup
Title: Re: Problem or not with Midnite 150
Post by: Halfcrazy on May 11, 2013, 07:04:45 PM
1 volt should not be any issue at all

Ryan
Title: Re: Problem or not with Midnite 150
Post by: suntex on May 11, 2013, 09:02:27 PM
Im really wanting to crank this system up....
What would the controller do if there was any problems or
what should I watch for...
Thanks
Title: Re: Problem or not with Midnite 150
Post by: TomW on May 11, 2013, 09:26:50 PM
Suntex;

I am far from an expert but I think the worst thing that will happen is a slight drop in effeciency from a perfectly matched system. Providing you do not exceed the input voltage on the Classic.

Good luck with it.

Tom
Title: Re: Problem or not with Midnite 150
Post by: Westbranch on May 11, 2013, 09:35:03 PM
to calm your fears, look at the variance that can exist between the panels of one type. 
The Polys are  +10%, - 5%, so for the panels you have that is +-9.35watts on a 187W panel at 28.5v.  1 volt variation is 3.5% of 28.5...

I bought a batch of  panels and they range from 18.11Vmp to 18.88Vmp, .77V variance, yet the power is Within the +5% variance.

ADD: most systems will only produce ~ 70% of name plate rating anyway, that 1 volt will be lost in the "noise"...