If the solar panel (only 1 panel used) max open circuit voltage (Voc) is 38 V
MPPT controller's max input voltage is 49.5 V, what should be the DC SPD (surge protector)'s maximum continuous operating voltage (Uc) be?

SPD is used at the output of solar panel.

Asking the question since most of the DC SPDs available in the market has their Uc at 600 or 1000 V. Since their Uc is significantly larger than 49.5 V, I am guessing using one these DC SPDs (600/1000 V) will not be useful in this case?

  • \$\begingroup\$ What voltage threat are you trying to protect against? \$\endgroup\$
    – Andy aka
    Mar 12, 2023 at 11:23
  • \$\begingroup\$ threat from indirect lightning \$\endgroup\$
    – asan123K
    Mar 12, 2023 at 12:47
  • \$\begingroup\$ What specification and what source impedance? \$\endgroup\$
    – Andy aka
    Mar 12, 2023 at 12:50
  • \$\begingroup\$ can you pls let me know what specification value you are asking ? and source impedance of what Solar panel or MPPT controller ? Also how do these relate to deciding SPD's Uc ? \$\endgroup\$
    – asan123K
    Mar 12, 2023 at 18:08
  • \$\begingroup\$ I can't tell you what spec you should use but, EN 61000-4-5 is good for indirect lightning but, you still have to select the peak voltage and decide whether your wiring is subject to a pulse with a 2 ohm or 40 ohm source impedance. You have choices to make. Then you might be able to use a TVS diode or maybe two or three in parallel. \$\endgroup\$
    – Andy aka
    Mar 12, 2023 at 19:36


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