solar panels perth australia image


As the thermometer rises , solar panels work less well

It surprises many solar owners that their solar installations often produce more power for the day in October and November than they do in Summer. Solar panels prefer it when the outside temperature is low, in fact 5 °C is ideal, and as it gets hotter they perform less efficiently. October, November and early December are typically sunny, long days, and relatively cool, and that is why production is often best then.


If you are comparing one solar panel against another, then on the panel datasheet look for the value "Temperature Coefficient (PMax)" or "Power Temperature Coefficient".

This will be shown as a negative percent with most regular poly and mono panels about -0.41% per ° C, with better panels around -0.36 per °C and the very best -0.29% per ° C.


Here are the values for some popular solar panels...

Winaico P6 (polycrystalline) -0.43% / ° C

Trina Honey (polycrystalline) -0.41% / ° C
Canadian Quintech (polycrystalline) -0.41% / ° C

ET Solar Elite (polycrystalline) -0.41% / ° C

Jinko Eagle (polycrystalline) -0.40% / °C
Q.Cells Q.Power (polycrystalline) -0.40% / ° C

Trina Honey Plus (monocrystalline) -0.39% / ° C

Longi LR6 (monocrystalline) -0.39% / ° C

Q.Cells Q.Peak Duo (half-cell mono) -0.37% / ° C

LG Neon 2 (monocrystalline) -0.37% / ° C

Canadian Solar KuPower (half-cell mono) -0.37% / ° C
REC Twinpeak (half cell poly) -0.36% / ° C
REC NPeak (half cell mono) -0.35% / ° C
SunPower E (monocrystalline) -0.35% / ° C
LG Neon R (monocrystalline) - 0.30% / ° C
SunPower X (monocrystalline) -0.29% / ° C


What it means in the real World.

If we compare a regular poly panel at -0.41% to a regular mono panel at -0.39% per ° C then that means 0.02% / ° C difference and so 0.6% on a typical 30 degree day. So one installation of polys might make 35kWh for the day and the monos 0.2kW more. Over a year that might mean $18 more in your pocket.


It's more significant when a poly and a half cell mono like REC NPeak are compared. There the difference is 0.06% / ° C difference so a full 0.6kWh per day more is produced by the half cell.


If you have deep pockets, then the Sunpower 'X' range and the 'R' range from LG have the lowest values providing a full 3% more power or a full 1 kWh per day more than a poly.


There is more to better and more expensive panels than their performance in the heat.
Half-Cell panels for instance also handle shade and low light better, and gains in that area can often be significantly higher than those achieved by better performance in the heat.