"Stand-Alone" system with Multiple PV Orientations (or "Grid-Connected" System with extra storage losses)

[smsas]

Good day,

I am trying to simulate a "stand-alone" system with multiple PV orientations. Each PV module will be connected to its own MPPT, so mismatch is not a problem. However, I can't find a way to aggregate the generation of all PV modules in a "stand-alone" system to check that the generation, together with the storage, is enough to satisfy a given load ("user's needs").
This is why I've used a "Grid-Connected" system with multiple PV orientations, no grid injection, with a storage system and "self-consumption" defined. However, in this system, the battery usage has an additional (and very high) energy penalty: "Battery Out, Inverter loss". For example, when there's no generation at night, I've seen that the one-way efficiency is 74% (meaning 1.35Wh to satisfy 1Wh of load), which doesn't make sense for my system. 

So, the general question I ask is: how can I better simulate my stand-alone system with multiple PV module orientations?

If there's no clear way, the more specific questions would be:
1. Can I define the PV generation in a "Stand-Alone" system so that the software will take the aggregated PV generation as input and simulate the storage and consumption? 
2. Can I define the parameters of the "battery inverter" in a "Grid-Connected" system so that the handling of the batteries in this system is more accurate (to my system)?

Thank you very much for your help!
Sebastian