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I have 2 solar panels (330 watt, 24 volt) which are installed and were used to 3 years, then I installed a larger system and disconnected these smaller solar panels. These were unused for more than 6 months. Now I checked the output of panels and multimeter shows 40 volt (multimeter is working properly, tested multiple times).

Also the junction box is too hot to touch, the diodes inside are too hot to touch. Some cells in solar panels have brown marks on sides. For now I have removed all the diodes to prevent further damage.

Has anyone experienced this before or know the reason for this? How can I resolve this?

Machavity
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Bharat D Bhadresha
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2 Answers2

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12V nominal panels will operate at about 19V open circuit, so the voltage is pretty normal for a 24V solar panel.

Harper - Reinstate Monica
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It does sound as if you have connected the panels in series. That would account for the increased voltage, which in turn could explain the damage being done.

The only other possibility I can think of is that the panels were d signed to output up to 40V but were being regulated down to 24V and the regulator failed. But that doesn't explain damage to the solar cells.

keshlam
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