Can I 3-4x over panel a single midnite classic?

[ddxv]

I'm getting some new panels and would like to check that they will work with my existing Classic 250. The panels are only for the winter months. Putting them into the Sizing Chart I see they are OK based on Max VOC but they are would be 3x over wattage recommending 3.1 Midnite Classic Controllers.

If I don't mind the extra wattage being clipped/lost, is this OK?

Will the Midnite Classic 250 still operate safely?

[mahendra]

Think it would be fine once it does not exceed your classic operating voltage and overcurrent protection devices(breakers/fuse)
You can set classics amp limit.

[mahendra]

Think it would be fine once it does not exceed your classic operating voltage and overcurrent protection devices(breakers/fuse)
You can set classics amp limit.

[Vic]

IMO, NO!!  This is a bad idea. Some over PVing MidNite CCs,  should be fine,  but having an array that is this magnitude of oversize,  seems NUTS, to me.

IIRC,  boB, has mentioned that Classics should be able to safely handle approximately 50% PV oversize could be OK.   BUT,  perhaps,  for a Classic 250 even a 50% PV oversize might be a bit excessive.

I am NOT boB,  but, I sure would not do this with any of my Clasics.

FWIW, etc,  Vic

[ddxv]

IMO, NO!!  This is a bad idea. Some over PVing MidNite CCs,  should be fine,  but having an array that is this magnitude of oversize,  seems NUTS, to me.

IIRC,  boB, has mentioned that Classics should be able to safely handle approximately 50% PV oversize could be OK.   BUT,  perhaps,  for a Classic 250 even a 50% PV oversize might be a bit excessive.

I am NOT boB,  but, I sure would not do this with any of my Clasics.

FWIW, etc,  Vic

Thank you, I appreciate both of your replies, and it's what I've seen in other places as well. The Midnite Classic and even newer ones like Hawkes Bay do *not* mention any *max watts* or *max amps* for the input, which always leads me back to thinking about this.

[mahendra]

Aren't you using Three Classic vs the 3.1 Classics as the array size tool indicates?
If not and only using one then that's grossly over paneling as DDXV mentioned. It is not recommended.

[Hockey]

IMO, NO!!  This is a bad idea. Some over PVing MidNite CCs,  should be fine,  but having an array that is this magnitude of oversize,  seems NUTS, to me.

IIRC,  boB, has mentioned that Classics should be able to safely handle approximately 50% PV oversize could be OK.  BUT,  perhaps,  for a Classic 250 even a 50% PV oversize might be a bit excessive.

I am NOT boB,  but, I sure would not do this with any of my Clasics.

FWIW, etc,  Vic

Thank you, I appreciate both of your replies, and it's what I've seen in other places as well. The Midnite Classic and even newer ones like Hawkes Bay do *not* mention any *max watts* or *max amps* for the input, which always leads me back to thinking about this.

My sense is that overpanelling is like speeding in a car.  One typically doesn't run into trouble if exceeding the limit marginally.  But 3 times the recommendation is excessive IMO.

That being said, if you have multiple fixed mount arrays with different azimuth and angle, that will come into play.  Different arrays will be at peak power production at different times of the day (azimuth).  So depending on orientation, you may never see all panels at peak production simultaneously. 

Some discussion of it here:
https://midniteftp.com/forum/index.php?topic=4221

And plenty of opinions elsewhere online.

[ddxv]

Some discussion of it here:
https://midniteftp.com/forum/index.php?topic=4221

And plenty of opinions elsewhere online.

Thanks for that link, it had a pretty good quote from BoB:

If you severely over-panel a Classic, or most MPPT controllers, it will current limit but it does this by raising the PV input voltage.

Running the controller at full output current at higher input voltage makes the controller run hotter is all. 

Yes, it might also take a bit longer to current limit. Have to take each situation individually.

boB

[boB]

Yes, that is about all that needs to be said for over-paneling.

Have a great week !

boB