ESS enabled on two easysolar units connected to the same battery bank

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mrft asked Feb 12, '20

ESS enabled on two easysolar units connected to the same battery bank

Good day all.

I have two easysolar units feeding two separate loads but connected to the same Pylontech battery bank. Both units have the ESS assistants installed. An issue I have picked up is that even though I set both unit's ESS systems up to Optimized (with BatteryLife), and Minimum SOC set at 60%, the grid does not come in when the batteries go below the set-point of 60%. Last night my batteries discharged to the cut off point of the Pylontech BMS system without the grid coming in. I can only deduce that the two ESS settings of the two inverters are conflicting with one another. When I set the one inverter's ESS to the Keep Batteries Charged option, the grid initiates on the other inverter and does not disengage the grid as it does when both inverters ESS assistant is set to Optimized. If the two ESS systems are indeed conflicting, can I set the one inverter's ESS to External Control. If I can, how do I set the parameters on this inverter to charge the batteries and disengage charging when the batteries reach a certain SOC ? Can I alternatively remove the one ESS assistant from one of the inverters and set the charging parameters via the MPPT charge controller? Your valued input will be much appreciated. Thank you.

ESS

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Alexandra ♦ commented · Feb 12, 2020 at 08:03 PM

Ideally you would want to set up and program a parallel system with data connections between the two easy Solars; and the Pylontech would have a data connection to the master so that it can report its charge state to the system directly.

ESS counts what it is using out of the battery as you have programmed in its capacity. it cannot count what the other unit is doing so it will draw down to where you set it, both units are drawing 45% - 45%x2 is 90%. Lithium have a fairly stable voltage so the system cannot work out state of charge from voltage unlike in lead acid and AGM banks.

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