Ohmic Losses with Power Optimizers

[stask]

Hi,

It seems that the optimization tool for wiring loss doesn't take into account power optimizers. The current considered is the Impp of the panel.

Is there a workaround?

Thanks

[Lazare Fesnien]

Hi,

The power optimizer definition and behavior are specific for each technology (and each manufacturer).

Therefore there is no general database, but only a list of available devices. The specifications are defined by the Manufacturers, and are not modifiable. You cannot add a new device by yourself.

After checking "Uses Optimizers" in the System design dialog, you will get a List of all available devices. The optimizers suited for your pre-defined PV module will appear in green.

You can get the Optimizer's specifications within the Optimizer's dialog, which is only available by the button "Open" after having chosen to use an optimizer.

This dialog proposes:

Main parameters : The parameters as defined in the database. Their nature and values are specific for each technology.

Input modules: Shows the limits (Voltage, Current, Power) for the connected PV module. In some cases you can specify here to connect several modules in series or parallel on one optimizer input.

Output I/V behaviour: The behavior is very specific to each technology. This pedagogic tool tries to explains the principles, by showing the I/V or P/V input and output curves in diverse situations.

This explains different kinds of mismatch, and the electrical shading of modules and sub-modules (you can modify the number of shaded sub-modules in each module).

As an example, it shows the effect of adding 4 optimizers in series.

Efficiency profile: The optimizers are not quite perfect; they suffer of a little inefficiency as specified here. The efficiency may be dependent on the "optimizing ratio" (current "buck ratio" or voltage).

Sizes: Usual page for sizes and comments. Pay attention to specificities for the use of some of these optimizers (suitability, compatibility, etc)

[stask]

Hi,

I was talking about the tool in the Ohmic Wiring Loss that allows to calculate the I^2R losses.

The current considered by this tool is the Impp of the panel, but this current is (almost) irrelevant when an optimizer is installed on the panel and it's output current is different than Impp. Most of the wires in the DC side will conduct the optimizers' output current and not Impp.