Factors Affecting Solar Panel Performance

There are five primary factors contributing to solar panel performing below it's published rating (in watts).  Lack of performance is likely a combination of these. 
​In this blog, I will take you through each of these factors and suggest ways to improve a panel's performance.
The slides are taken from our seminar; Designing the Proper Solar System for Your Boat  (Under HANDY INFO)

---

---

Solar panel performance decreases as the temperature of the solar cells increases. 
​The rated capacity of a solar panel in watts is based on its capacity under Standard Test Conditions (STC).  The cells of the panel typically operate much warmer than STC (77F).

---

Custom Marine Products has developed several ways to cool a panel to achieve maximum performance.
The following slide addresses how CMP has developed a system to cool walk-on semi-rigid solar panels to optimize performance.

---

Solar panel performance decreases at less than optimal sun angles of incidence.

---

Tilting and rotating a solar panel to achieve optimum sun angles can improve watts generated in a day by 40%

---

Shading can have a significant on the amount of power produced by a solar panel. 
Custom Marine Products has developed a series of Shade Tolerant panels that minimize the effects of shading.

---

The quality of the solar cells used in a solar panel will have a direct effect on the overall performance of the panel.
Our customers have reported that their panels sometimes outperform the stated capacity rating at STC. 
​This is because CMP only uses the highest quality cells available.

---

Below is an example of how the four factors mentioned could affect the performance (watts produced per day) of a solar panel.

---

There is a 5th factor unrelated to the solar panel itself that effects the solar power production.  This factor is the battery bank's ability to accept a solar charge.
The solar controller will pull power from the solar panel based on the how much power the battery bank will accept.
A fully charged battery bank, for example, will not accept a solar charge and thus the solar panel may produce only a minimum amount of power to trickle charge the battery bank.
The hungrier the batteries, the more solar power they will accept.