question

mihair avatar image
mihair asked

ESS system speed as a function of system state

Hi guys,


Closely monitoring my ESS system I have noticed that when this is on #1 #2 or #5 or #7 states reaction on changings is much slower than in normal operating state.

Example: Let's presume the system SOC is less than Active SOC limit with Optimised with Battery Life activated and is displaying #1 and #2 on CCGX. PV inverter is in parallel with AC input 1 and generates power to partially cover the consumption, the difference being taken from the grid. Suddenly the load disappear. In that very moment all the PV power is injected into the grid and the system is unable to redirect it to battery in less than 60 seconds.

In normal operating condition, when the battery SOC is greater than Active SOC limit, the system redirects the power to battery in few seconds.

Can someone explain why? Is this normal or there is something wrongly configured in my system?


Thank you,

Mihai

MultiPlus Quattro Inverter ChargerESSCCGX Color Control
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2 Answers
Izak (Victron Energy Staff) avatar image
Izak (Victron Energy Staff) answered ·

This is a partial answer, I don't presently have the time to fully research it, but I'll give you something to work with. When #1 shows (SOC is low), the inverter component in the Multi is turned off. Even though a grid setpoint is continually calculated (so that the Multi will import that energy from the PV inverter), the normal mechanism that operates in Optimised mode is switched off, so the response will be different. In other words I don't think your system is incorrectly configured.

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mihair avatar image mihair commented ·

Hi Izak,


First of all, thank you so much for your time and response.

I fully agree with you that turning the inverter off is the root cause for slowing the response of ESS's negative feedback loop. It can be easily seen and simulated by turning the inverter power to zero in ESS menu.

I hope that R&D will find some time to improve this behaviour and really appreciate their effort in making this system cope with all possible installation scenarios.


Keep up the great work!

Mihai

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Jean Jacques de Jong avatar image
Jean Jacques de Jong answered ·

Example shown on my Home Assistant dashboard where my MultiPlus/ESS reaction time is so slow that significant energy is injected into the grid despite a significant energy consumption. ESS showing #1 and #2. I had an oven turned on, generating a 3 KW spike of less than 15s every 1min. A somewhat correct behavior only appears around 13:30 (power pulled from the grid during an oven consumption spike), after 6 minutes of nonsensical behavior (like injecting power into the grid during an oven consumption spike). Between the oven spikes, the excess solar power should charge the battery, which only happens 30 seconds after each spike has fallen.

Note also that the sampling period of the MultiPlus power sensors is 15s, which is way too long for a proper regulation... Is that sampling period just for display, or is it also internal? Maybe the displayed values do not follow the reality of what is happening internally?

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