[hbogert]

I keep hearing of these magical lifetimes. I've had 2 different brands and multiple panels are taken out of the circuit because they degraded too much.

My neighbour has the same panels but never looks at the output. I told him to check them and he was shocked. How many others are there they simply don't check the output and keep spouting that panels have multi decade lifetimes.

[mgraupner]

I'm in my 13 year and with 10 kWp I'm still generating a maximum of about 8000 W on warm days (which lowers the efficiency). I don't know any neighbours or friends who have had to replace a module.

[abe_m]

What what your time vs degradation? I see quite a few solar panels in my area showing up on Facebook Marketplace and other online classifieds that seem to be about 10 years old being sold for a "bigger system". But I'm curious if the real story is that straight forward? Are they significantly degraded? Did the controls or inverters fail, and the owner decided it wasn't worth the hastle? I don't know. The headline price seems attractive, but if they're only putting out 10% of name plate, not worth the effort to install.

[hbogert]

this was after 5 years

It was so significant that one of the 2 strings, 6 panels each, simply shut off especially during peak hours because the inverter's minimal input voltage wasn't met (during peak voltage usually drops due to negative heat coefficient). 1 simply was broken and was bypassed by the.. bypass diodes i guess. And another was at a third. But again, the lower voltage was a much bigger problem than the input.

problem is, you can only measure this very well under load. So taking your multi meter to the place of sale might not say that much. `It might though for the really broken ones.