Selectronic Inverter + PV Inverter + Batteries

Does Selectronic have a 1:1 rule like Victron does for AC coupling?

If I have a Selectronic 20Kw Inverter with 2 x 15Kw Symo Fronius PV inverters, how much LiFePO4 battery capacity must I have?

I have read up on Selctronic as much as I can but there is not that much out there (unlike Victron where they are countless posts in forums all about them) and have seen that I can have 2 x the capacity of the Selctronic Inverter in PV Inverters (ie, so for a 20Kw Selectronic I could have 40Kw of PV inverter)…but I can see nothing about how much battery power is required.

Any thoughts on this ?

@Ohms_Cousin Selectronic is only limited to the 1:1 rule when used with a Generic AC coupled solar inverter. If you use a ‘Selectronic certified’ or ‘Scert’ solar inverter such as a Fronius Primo, Symo, or ABB (Fimer) then you have a 2:1 ratio, plus more solar can be DC-coupled if required. Note, the Scert inverters have to be ordered and cost a few hundred more than the standard inverter.

In regards to battery capacity, the minimum battery size will need to be able to meet the demand of the inverters continuous output power rating. However, the SP-link software enables you to de-rate the inverter if the battery capacity is very limited (although this will only really work with a grid connected system)

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Hey Svarky,

Thanks for the info. So how much LiFePO4 would the 120v 7.5KW Selectronic need?

Would that be 7.5KW/Hrs of battery capacity or is battery needed worked out in amp/hrs capacity of the battery pack?