Array sizing/configuration determination

[Westbranch]

thanks
Vic, that 'main menu' button worked OK ..

Eric

[Vic]

OK, good, Eric,

But,  as long as we are talking about things which one has trouble finding,
WHERE IS that XLS file you mentioned ?  Thanks  Vic

[Westbranch]

It is in this thread and Kent posted it Jan 13.

look at the bottom of his post, under the _________ line
Eric

[Vic]

OK,  Thought later that it might have been that XLS.   Originally thought that MN had come up with a sizing spreadsheet.  Thanks Eric,   Vic

[joeedens]

I tried the excel file again and I'm still not able to run it.  Still says it is encrypted.  It must have something to do with me being on a Mac and using Numbers.  Numbers can import excel files, I've done it before but there is something about this one that it doesn't like.  So I guess the only option is to "play with" the wizard.  Its frustrating to just randomly push buttons hoping that you stumble onto the one undocumented feature that you need!

[Westbranch]

Joe, not sure if your machine shows it, there is a very slight shading , but the only cells you can make entries in are B4 to B9, B12 to B15, B18, B19
HTH

Eric

edit to add B4 to B9, missed

[RegGuheert]

This spreadsheet is hardly competition for the simulation in terms of cuteness.  But you don't have to run the whole simulation to try various PV arrays.

This is a work in progress.  Batteries above 48 volts aren't considered.  There may be other problems too.

Great spreadsheet, Kent!  Thanks for posting this!

Just one point that I would like to make about the conclusions of the spreadsheet is that it seems to give equal weight to staying below VOC and staying below the max power of the array.  In the case I just ran on a system I have just installed, the sheet noted that the array is "Too Big" for the Classic 200 while everything is "OK" with another brand's 200V controller.  But the fact is that system would be operated within 1% of the damage voltage in cold weather.  By contrast, the Classic 200 may *rarely* go over the 70A current limit in cold weather but that is simply a sizing consideration not a failure mode.  Might I recommend adding some margin, say 90%, to the "Absolute Max VOC" number in your sheet and only giving an OK if the VOC stays below that margin value.

It's just a nit, but I think it understates the importance of the extra damage margin that comes with the Classic Controllers.

Thanks again for posting this!

Reg

[Kent0]

I've updated the spreadsheet after being alerted to an error in the temperature corrections.
Despite the file extension, this is an Excel file with no macros.

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[boB]

Kent, just a teeny nit pick if it matters but I notice that you show the absolute max Voc for the Apollo 200 HV as 200 Volts and the 150 as 140.  Remember that the Apollo stops running at somewhat less than 200 Volts. It's 200V rating is basically its hypervoc equivalent like the 150's max V is 150.  Can't remember exactly but I thought it was like, 165 Volts for the T-200 HV ?  And doesn't the FM80 stop at 145 or somewhat less than 150V ?

boB

[Kent0]

boB,

You know the competition better than I do. I corrected the voltage limits for the Apollo controllers accordingly.

One thing I should mention is that the design check uses the manufacturers' recommendations for array size. Since these devices are all thermally protected the array size limit isn't very significant. However, for the same output current rating, the recommended array sizes have quite a range. Morningstar's recommendation is the most conservative, probably because it is passively cooled. Apollo's are based on max current at equalizing voltage. The Midnite recommendations are based, more or less, on the values on the published chart. In the spreadsheet, I used the output power at 14.4 x n volts. On the charts I see the power computed at 14.4 volts, 28.7 volts, 58.4 volts, which is not a consistent sequence (2 x 28.7 = 57.4). Obviously the input power from the PV array could be a little more, by enough to account for the losses in controller at a minimum, and even a little more depending on the climate where the PV array is located.


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[boB]

Thanks for updating the XLS file, Kent.

I just now noticed that even the earlier version had the max operating Voc...
It just needed that one tweak that you just did.

boB

PS...  Some of the MX60s would operate up to 146 Volts