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george123 avatar image
george123 asked

VE-MPPT calculator question

I just ran the calculator tool using two SPM215-24 modules connected in parallel and the controller was the MPPT 100/50. The configuration was Accepted. When I looked at the calculation tap in the work book I noticed in the module Info there was a RED set of numbers that read 35.84 A Impp output @25 degrees C. What does this mean?

Also on the FORMS tab where it states Max. current @MPP min. temp 39.8A and Max. current @ MPP max temp 28.9 A is this the current that I could expect the battery will receive under bulk conditions assuming the sun is directly over head.

I wish there was a good document that explained how to interpret the spread sheet output tabs.

Thanks

MPPT Controllers
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1 Answer
JohnC avatar image
JohnC answered ·

Hi @george123

Try using this calculator, more user friendly: https://mppt.victronenergy.com/

It will tell you what mppt to select, and if you click on 'Calculations' there's a figure there in red too, which may be an undetermined level for mppt derating at low temps.

Note that panels can produce more W when it's cold, and they may calculate those max A's at a typical Absorb V (say 14.5) rather than a nominal 12V.

These calcs are all about being 'within the ballpark', and it's hard to nail a typical solar day down when you consider it's bellcurve. But in my link you can type in your town and it'll have a go with an annual production graph..

Try it.

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