Replacing bypass Diodes

KhellSkKhellSk Registered Users Posts: 82 ✭✭
Hello all! 

I have these 32cells panels[15.9v 19.8Voc 3.02a 3.35Asc]
 that came with bypass diode named MR750 w9something*. When I looked mr750 up it gave me
https://www.digikey.ca/product-detail/en/on-semiconductor/MR750/MR750-ND/1482588

The new ones are 15SQ045
https://www.amazon.ca/gp/aw/d/B07CHFJ5WC

Maximum Average Forward Current: 15 A MP 
Forward Current (at DC10A): 0.55V 
Maximum DC Blocking Voltage: 45V 

i ordered them to make blocking diode on the parallel array but when I saw the specs were better than the bypass ones already installed i wondered if it would work ?

Thanks 
_____________________________________________
[2x Flooded  6v 210ah][12v 30a 400wMax CC]
[5x 48w 15.9Vmp + 1x 100w 17Vmp]


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Comments

  • jonrjonr Solar Expert Posts: 1,266 ✭✭✭✭
    It will work with less loss.   On the other hand, unless there is shading, bypass diodes sit there and do nothing.   So don't expect to see a difference.

    I am available for custom hardware/firmware development

  • KhellSkKhellSk Registered Users Posts: 82 ✭✭
    jonr said:
    It will work with less loss.   On the other hand, unless there is shading, bypass diodes sit there and do nothing.   So don't expect to see a difference.
    There is shading all day long. It is why I think its worth the hassle.
    _____________________________________________
    [2x Flooded  6v 210ah][12v 30a 400wMax CC]
    [5x 48w 15.9Vmp + 1x 100w 17Vmp]


  • jonrjonr Solar Expert Posts: 1,266 ✭✭✭✭
    edited December 2018 #4
    All day shading is likely to never produce satisfactory results.


    Here is a diode that performs about 20x better than your new ones:

    http://www.ti.com/lit/ds/symlink/sm74611.pdf
     

    I am available for custom hardware/firmware development

  • KhellSkKhellSk Registered Users Posts: 82 ✭✭
    jonr said:
    All day shading is likely to never produce satisfactory results.


    Here is a diode that performs about 20x better than your new ones:

    http://www.ti.com/lit/ds/symlink/sm74611.pdf
     

    wow those are nice!! I dont have gear for soldering and skills to fit those on my current system. Good to know .
    _____________________________________________
    [2x Flooded  6v 210ah][12v 30a 400wMax CC]
    [5x 48w 15.9Vmp + 1x 100w 17Vmp]


  • NANOcontrolNANOcontrol Registered Users Posts: 121 ✭✭✭
    There is a solar panel with bypass diodes on EVERY cell.  They do a great demo with a water pump comparing a standard panel with theirs blocking out one or two cells at a time.  An excellent example of the DOPELER effect, the faster ideas come at you the better they sound.  Real life situations where this would make any difference are almost non existent.  My opinion is it is a wasted effort.  Bypass diodes protect the cells.  In light shading it makes no difference. 
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