I added a hybrid inverter to ‘My Components’ but can’t add a battery to it in the Inverter Task.

If you are trying to use custom hybrid Inverter and battery components - you will need to make sure you have added the battery as its own component. You can do this under Components > Edit Batteries. This is true even for all-in-one systems, Easy PV will need to know the battery details for self-consumption calculations. 

Make sure you set its compatibility with your custom inverter. For more detailed instructions, take a look at our guide to setting up batteries in Easy PV.