Current configuration: Victron 100/50 mppt. 6x100w eco worthy panels, 3s2p.
Panel specs: 5.78amp 18v capacity.
This setup has historically yielded a maximum of 420watts.
Location: Canada.
New setup: adding 3 more 100w panels for a total of 900w, 3s3p.
Will the Victron 100/50 be adequate?
With “18v capacity” you mean 18 V open circuit voltage (VOC)? What is the VOC voltage of the new panels?
Only if the voltages of the three strings are very close to each other can they be connected without problems. Otherwise, current would flow from the string with the higher voltage into the strings with the lower voltage. Just as you can’t connect a 12V battery and a 24V battery in parallel, you can’t do that with PV strings.
Voc is 22.7 volts. All 9 panels are identical.
This is OK, since 3 x 22.7V is below the 100V maximum of the 100/50. The short circuit current of all panels is 5.78A? And what’s the voltage of the battery? The 100/50 can charge a battery with a maximum of 50A, and this is 700W for a 12V battery or 1400W for a 24V battery. So for a 12V battery the 9 panels don’t fit really good.
The battery is 12V 300AH.
As charging is typically at 13.5V or above, a nominal 12V battery at 50A is 675W. Overpanelling by 30% is typically acceptable which is 880W, so 900W is within normal range catering for northern attitudes where peak irradiation is less than the panel rating.
Thank you. Is there any point/upside to switching over to a larger mppt?
If the max you see is 420W from 600W installed then pro rated you will see 630W from 900W installed which is inside the controllers capability. I would add the panels and see how it goes.
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