# Module Mismatch Effect

Even in a single production run of modules, there is a variation in module performance, and modules are normally binned per their power output by manufacturers. A given power can be achieved by different combinations of current and voltage, so voltage and current distributions exist within these module power bins. These differences between modules cause mismatch effects when modules are connected in series and parallel, with the most significant effects being due to current mismatch between modules connected in series. Some manufacturers will supply modules binned by current within each power bin (maybe 5% of the time). The Module Mismatch Effect is a type of electrical mismatch and could be considered at the same time as other mismatch effects, however it is desirable to quantify the impacts of module mismatch separately from other mismatch effects.

For Release 1, users will enter a single value for the Module Mismatch Effect \(∆_{\text{mm}}\). This is simply applied to the plant array output to calculate the plant array output including these effects such that:

$$P_{Parray,mm}\left( t \right) = \left( 1 + \frac{\Delta_{\text{mm}}}{100%} \right) \bullet P_{Parray,mpp,other}\left( t \right)$$

Future versions of SolarFarmer may allow a better analysis of module mismatch, based on voltage and current spreads within the bins.

To consider the Module Mismatch Effect alongside other conversion effects in the mismatch calculation, an adjustment to the current from each submodule is calculated as:

$$\eta_{submod,mm} = \left( 1 + \frac{\Delta_{\text{mm}}}{100%} \right)$$