ESS Peak Shaving with Battery Life and Charging Schedules

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mito asked Jul 26, '23

ESS Peak Shaving with Battery Life and Charging Schedules

Need some help to understand following :
Configuration:
-1 x Quattro 10000 V505
-3 x Pylon 15 KWh
-Cerbo V3.01
-ET112
-NO PV
-Grid Set-point

ESS Peak Shaving and batteries charging scheme Implementation

Reason for help is as follows:

System works fine . As Loads peak demand are larger than Grid Setpoint, Inverter start to assist and load is served both by grid at setpoint and Inverter/ batteries, until load demand reduces, or SOC from batteries achieve lower configurted SOC% .

At this point Grid starts to serve 100% of load demand, regardless of Grid setpoint, what is OK.

But the point is that I was expecting that Grid will also start to charge batteries, so to have them fully charged before loads demand peak shaving back again.
One way to cope this is opening a Charge Schedule Window to charge batteries during the night, but it doesn´t solve the problem of multiple load peaks during the same day.

How to allow Grid to serve loads and charge batteries at the same time, during the peak saving period, when SOC has achieved lower limit, instead of only serving loads. Scheduled charging is not the answer , because we cannot anticipate when the extra loads will be there.

Thanks

ess settings scheduled charge

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Alexandra ♦ commented · Jul 26, 2023 at 05:34 PM

What is your input current limit?

And is it lower than loads and the extra amps for battery charging?

Why are you using ESS when you have no PV? How does that fit into the design?

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Answer 1 · 2023-07-26T18:43:04Z

mito answered · Jul 26, 2023 at 06:43 PM

My answers to your quest

-What is your input current limit?

ANSWER:25 amps. It should be enough to charge up to 5 KW batteries.

-And is it lower than loads and the extra amps for battery charging?

ANSWER:Loads are paralel to inverter.
Inverter is assisting loads with extra peak requirements and batteries charging current

-Why are you using ESS when you have no PV? How does that fit into the design?

ANSWER: Because it is a Grid Paralel configuration where Inverter only support assisting power to loads from Batteries when is required. Grid Power never passthrough Inverter to outputs (outputs are not used). Inverter has not to be oversized.

Things works fine, with the exception to recharge batteries from grid, after a peakshaving cycle. Option is to stablishing some sequential charging schedules, but it should not be the best option

I discovered in the ESS manual a description that perhaps explain the issue, but I think it is not well documented. Perhaps you can help to understand when it referres to use Peak Shaving after the Energy Meter (see my underlined to Victron document):

" From ESS Manual

4.3.7. Peak shaving

(Applies only when BatteryLife is enabled - it is always on in 'Keep batteries charged mode')

Using the Peak Shaving option it is possible to always let the system keep PowerAssisting when the loads exceed the AC input current limit and it is required, or only above the Minimum SOC parameter.

As soon as the peak is over, it will recharge the battery using power from the grid, while still prioritising solar.

Note that there is a 5% hysteresis; If the Minimum SOC is set to 50%, it will then start recharging back to that 50% only once (by peak shaving) the battery has dropped to 45%.

Also note that this works for the critical loads on the AC output only, not those connected to an energy meter.

The default setting when using the Optimised modes is 'Above minimum SOC only.' Use this option in systems that do not perform peak shaving."

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Alexandra ♦ commented · Jul 26, 2023 at 07:03 PM

The input current limit will allow 5kw but if your load is higher than 5kw it wont charge the battery. The load will need to be lower than that.

You don't need ESS to peak shave and power assist. It does that without it.

Take it off and see how the system be haves. It is designed for systems with PV that have cycling batteries who only want to charge them with PV. You dont have PV and would need the grid to keep the batteries charged.

The statement about the energy meter is also for those who set up the meter to meter (and log to the vrm) other circuits not on the output of the inverter system.

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Answer 2 · 2023-07-26T19:42:46Z

mito answered · Jul 26, 2023 at 07:42 PM

Problem was solved stablishing a right configuration for Grid Setpoint from Energy Meter.
It is really needed to work around it for charging batteries after a Peak shaving Cycle
As in grid paralel configuration, main load current does not pass through Inverter, Input Current Limit is not such important

Txs
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