Panel Efficiency  

How much power do you really get from a solar panel?

Solar panels come in many different sizes and from many different companies. They all have the same basic characteristics. They are comprised of photo voltaic cells that convert the light from the sun to electric energy.

A solar system is the entire system that goes from the solar panel through electrical cable to the DC power inverter, and out the other side as AC power into your home electrical panel. Each of these separate parts will lose a certain amount of power, as it travels from the panels to your breaker panel. This is a normal process and can be calculated for each solar system based on the components of the system.


I used to talk about all the factors that would reduce panel efficiency and, how this loss of power affected the production of the entire system. I do not have to do that anymore.

Each panel now comes with either an NOCT or an NMOT rating for the panel.

These two ratings are effectively the same thing - they indicate the normal peak power for a panel in real world conditions. I have included below the data sheets for three of the most popular panels used in Yucatan. These are high end panels and are close to or at the top of what each manufacturing company has to offer.

ECS uses JA Solar panels. We have determined that they are the best choice for our installations and the data sheets bear this out.


There are a number of things to keep in mind when deciding on the panel you want for your system and I will highlight each of these and see how the panels stack up against each other.

What we will be looking at, are the things that most affect how well a solar panel works in the conditions we face here in Yucatan and on the Emerald Coast. These include: NOCT rating for the panel, PMAX for the panel, Panel efficiency and Low light productivity. So, let's have a look at the three panels.

JA Solar

NOCT = 306 This means expected performance of the 405 panel is 306-watts or 75.56% efficiency

Temperature coefficient of Pmax = -0.35% per degree of temperature rise.


Module efficiency = 20.2%

Low light performance is excellent.

The key specifications we want to look at are:

Trina Solar

NOCT = 302 This means expected performance of the 400 panel is 302-watts or 75.5% efficiency

Temperature coefficient of Pmax = -0.37% per degree of temperature rise.


Module efficiency = 19.7%

Low light performance is excellent.

Canadian Solar

NOCT = 298 This means expected performance of the 400 panel is 298-watts or 74.5% efficiency

Temperature coefficient of Pmax = -0.36% per degree of temperature rise.


Module efficiency = 20.16%

Low light performance is excellent.

What conclusions can be drawn from this comparison?

1) All panels noted above are very similar however there is a clear winner.

2) The JA Solar panel has higher Module Efficiency, higher NOCT efficiency and a lower Temperature coefficient of Pmax then either of the other models.


The JA Solar panel will out perform either of these other panels when it comes to the following conditions:

Under normal operating conditions, due to the higher performance percentage.

Low light (early in the morning and later in the day, when shaded or when the sunlight is diffused).

During times of high heat, the temp. coefficient for this panel is lower than the other two meaning, it will operate with less power degradation during high heat times of the year.

At Emerald Coast Solar, this is just one example of the many investigations we do to ensure you have the most efficient solar system available.

We also conduct head to head system comparisons between Enphase and String inverters. Check out our results here - 


We monitor all our Enphase systems for both production levels and operational issues.


Wouldn't it be nice, if there was a problem with your system, to get an email from the install company to let you know that they noted an issue  and repaired it, without you even being aware of the issue and, without them coming to your home?


We can do that.


Or, what if there is a problem and a micro-inverter needs to be replaced. Same thing, you get a call from the install company to say they have noted the issue tried to correct it, could not. They have filed a warranty claim on your behalf, and have gotten it approved. They are now calling to schedule a time to come and replace the micro-inverter.


We can and have done this. All before the client even was aware there was a problem.

No other company in Yucatan offers the same level of support and commitment to clients as we do.


We owe a lot of this ability to the Enphase micro-inverter systems. Without the panel level monitoring, this level of customer care would be impossible.

   Emerald Coast Solar

Putting the power of the sun to work for you