Help Me Compare Temperature Coefficients

[lkstaack]

I plan on using temperature coefficient (TC) as a specification to compare different panels. However, not all manufactures provide the same specifications. Some express TC as a range, and others express TC in terms of the Isc, Voc, and Pmax. LG also provides NOCT and Pmpp specs. What are the specs that I should be looking at if I am concerned about the effect of ambient heat impacting solar production?

My LG 280 Mono panels are being replaced under warranty because they have degraded 23% over 7 years. LG isn't in the residential solar business anymore, so they are satisfying the warranty with cash instead of replacements to the tune of $1/watt. Of course, I can't replace them at that price, so I'm looking at other panels. My solar installer is giving me a choice of panels, including LONGi 60HPB-355, Canadian CS3N-395MS, and United Renewables FBM400MFG-BB. To their credit, my solar installer is not charging for labor, as part of their installation warranty.

My Southern California ground mount panels have an almost unobscured view of the south, south-west with a 20% tilt. They get really hot in late summer, so their ability to produce during this time is affected. Which temperature coefficient specification should I be looking at?

[Calsun]

I would not worry about this as all panels produce less output with higher ambient temperatures. You can alter the tilt angle to offset this is maximum power during the summer months is your objective.

I would look at the panels with the longest life. The Sunpower commercial panels that were installed in 2012 still provide 99% of their output ten years later and they have a 25-year warranty. Important to pick a panel from a company that is likely to be around 20 years from now and that has a good reputation for supporting their products. Knowing which panels the dealers are having to replace would be important information.

The problem with a company like LG is that they have their fingers in many pies and can abandon a business without a lot of thought. If a company derives 100% of its profits from solar products it is quite different. The LG panels were most likel produced by another company and the LG product manager chose the lowest cost provider.

[J.P.M.]

The problem with a company like LG is that they have their fingers in many pies and can abandon a business without a lot of thought. I

As they have recently done.

[SunEagle]

Until someone tells me different Calsun has been banned due to the nine posts that seem a little off.