This is what a warm connector looks like in a thermal image compared to one operating normally. For context, connector temperature can be affected by irradiance, system configuration, current, ambient temperature, humidity, wind speed, shading, connector location, and even how the thermal image is taken. At HelioVolta, we developed our own field process to categorize solar connectors. Curious how the rest of the industry does it. What method do you use?
Nice. What’s the differential you would call something critical?
I consider 30F temperature rise from ambient to be suspicious. In your image here the conductor seems to be equally heated. I’d check current flow with my amp meter and the surrounding strings to see if it’s just a string that’s moving more wattage than the others. Spot check that conductor at other points but I’ve never seen a high resistance connector radiate heat that far up the conductor.
For once, the connector doesn't seem to be the culprit since the whole wire is hot. There is a strong production imbalance among these strings.
Thermal imaging is an excellent inspection method. It is also important to ensure that connectors are not tightly pressed against or directly attached to excessively hot mounting brackets. I have seen many cases of improper installation leading to harsh operating conditions and misuse of connectors, resulting in significant losses. Therefore, attention to detail is critical for a PV power station.
Let’s assume someone says “15degree difference. Not a big deal”. Trust me, David, there are many thinking that way out there. So what if I tell you that those 15 degrees will cut the lifetime of the connector AND the cable (!) by more than 50%. For those who don’t get it, it means shortening the life of 25 years to somewhere around 12 years. Not even taking into consideration that the temperature will be raising over the time. Some time ago, I wrote an article about that phenomenon: https://www.linkedin.com/pulse/silent-saboteur-stealing-your-solar-dreams-jan-mastny-lm06e?utm_source=share&utm_medium=member_ios&utm_campaign=share_via
As all the causal factors you mention lead to a thermal outcome, perhaps the better action to take is to directly monitor the temperature of the connector rather than relying on categorisation by look/colour?
Mmmmm, that’s not exactly right… This looks more like an almagamation of multiple images or an AI approximation… Having thermally inspected thousands of MC4 connectors, I have yet to see a single hot connection that had anywhere close to the uniformity of this image. Why don’t we show real images of real issues so that people can actually see them and we can show that we are talking about what will be found in the real world…?
IEC 62446 , almost 10 years old but thorough. I add amperage, voltage, insulation resistance and irradiance readings into a detailed spread sheet for historical and traceable data year after year.