If you are designing in Studio and notice that the panels that you layout are extremely large, then it is likely that the dimensions of the panel have been entered in the incorrect units.
In OpenSolar, enter in the dimensions of the panel in metres. If these are accidentally entered in as millimetres then it would cause the panels to be extremely large.
In order to update this then simply go back to the Control zone and then click on "Manage" beneath Modules. Then edit the module that it is occurring for.
Ensure that you click Save when you have finished updating this.