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Wrenches,<br>
When adding a modern charge controller to an existing off grid
system as part of an array upgrade, we often have to mix charge
controllers and their widely differing control algorithms. A common
combination is to add a new array with a FM60 or Classic to an older
system with a C40 or a Solar Boost SB50. Typically, the new array is
larger than the original array, but not always.<br>
<br>
How do you adjust controllers when the bulk/absorption/float
transitions vary widely? Typically we set to the same voltages,
figuring that the controllers will determine their own respective
dominance - that is, which unit drops out first in absorption), and
it should have little effect on finishing a charge cycle. But can
you describe (and defend) any particular ways of setting up
unmatched combinations, such as I have described? For example, the
C40 has a fixed two-hour absorption, and the FM and Classic have
minimum and maximum times (the FM just max, along with absorb end
amps). Typically the more expensive and more efficient controller
will be on the larger array. How would you set up this combination,
and other common situations?<br>
<br>
Thank you in advance for the collective wisdom, as usual. <br>
Allan<br>
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<font face="Times New Roman, Times, serif"><b>Allan Sindelar</b></font><br>
<small><a href="mailto:Allan@positiveenergysolar.com"><font
face="Times New Roman, Times, serif" color="#000099"><u>Allan@positiveenergysolar.com</u></font></a></small><font
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<span style="font-size: 10pt;">NABCEP Certified Photovoltaic
Installer<br>
NABCEP Certified Technical Sales Professional<br>
New Mexico EE98J Journeyman Electrician<br>
Founder and Chief Technology Officer<br>
<b>Positive Energy, Inc.</b><br>
3209 Richards Lane (note new address)<br>
Santa Fe, New Mexico 87507<br>
<b>505 424-1112</b><br>
<a href="http://www.positiveenergysolar.com/" target="_blank"><u>www.positiveenergysolar.com</u></a><o:p></o:p></span></font>
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