ESS scheduled charging not behaving like expected

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janvi asked Aug 2, '23

ESS scheduled charging not behaving like expected

A Multiplus2 ESS with Pylontech LiFepo Batterie is mounted inside a building without public grid. The MP2 input is wired to the neighbours building where public grid is available. This allows to to charge battery from grid as well as contributing to the neighbours power consumptions and feed excess power back to the grid.

At sunrise, the MPPT output current reduces the battery discharge and contributes to the own AC loads. If PV current is sufficient, Multiplus stops discharging mode and switches to external control. This external control is obviosly received by the Pylontech CAN command what calls for charging.

As the neighbours building has typical high demand of power in the morning, I would prefere to delay the battery charge current until a fix time in afternoon (or a time depending from a weather forecast). This should allow the ESS to feed into the grid early in the morning contributing to a reduction of the neighbours high grid load in this hours.

I tried the ESS Setup-Scheduled_charge_levels. If time is active, it works always using 100% capacity of multiplus chargers from grid independend from available MPPT DC power.

How is it possible to limit scheduled charge to available excess DC power and disable any charging before the scheduled hours elapsed ?`

Will a RS485 grid meter signal from the neighbour help in this case ?

Related Victron Questions:

https://community.victronenergy.com/questions/57222/requirement-for-delayed-battery-charging-from-main.html

MultiPlus Quattro Inverter Charger battery charging ESS scheduled charge

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Alexandra ♦ commented · Aug 02, 2023 at 08:03 AM

@Janvi

Node red would allow control like that.

The basic ESS you would have to set battery life off and have a low soc in case of grid faliure to allow the earlier feddback. Then the scheduled charge later to get it to 100%

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janvi Alexandra ♦ commented · Aug 03, 2023 at 08:34 AM

Playing around with ESS and battery setup I was not able to stop charging the battery. It was possible to

- start charge at scheduled time with full Multiplus current from grid

- feed back to grid with full multiplus inverter current from battery

I was not able to feed back to grid with available excess DC power while battery is waiting with a lower charge percentage. Battery charging always prevails over grid feedback.

Unfortunately, my DVCC is now always "forced on" and I cannot switch off like it was off before. As far as I understand it should be ON with CAN bus BMS from Pylontech what allows the Cerbo to overwrite the values what come from Pylon CAN BMS (?).

Anyhow, the battery charging current is reduced significant at 52,4V threshold and grid feedback power rises to maximum MP2 power. The Pylon BMS obviosly calls for 53,2V. The setup of

DVCC->MaximumChargeCurrent = 0 Amp

DVCC->LimitBattery Voltage = 48 Volt

do not show any effect in reducing the charge currents,. no matter if ESS mode is with or without optimized BatteryLife. ESS shows only entry possibilites for minimum SOC but not for maximum SOC. No other way to prevent battery charging ?

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