question

tdl avatar image
tdl asked

Dynamic ESS Why discharge and immediately reload the battery at peak time?

Hi

I see that today, during peak time, the battery was discharging to compensate consumption (no problem with that, then after, the power was used to reload the battery still during peak time. I do not expect this. I expect that the battery should be first used to compensate peak time usage, maybe if it is economically relevant, recharge it at night, to again compensate consumption the day after.

Here are the relevant graphs:

overview.png

and

energy.png

you see that the battery to grid between 17.00-17.59 and after 18.00-18.59 was Grid to battery.

I would assume that the optimal would be to use the battery to compensate consumption up to 22.00 ,when we switch to low price hours, use the grid for the consumption and also reload the battery to cover the consumption of the next day up the sun takes over (so maybe not 100% if it won't be needed the day after until the sun appears).

Is there something wrong in my setup?

config.png

Note Firmware version of MultiPlus-II 48/5000/70-48 if 510 and Color control GX is v3.40~13 and battery is BYD B-Box Pro 10

dynamic ess
overview.png (38.0 KiB)
energy.png (56.1 KiB)
config.png (71.0 KiB)
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4 Answers
tdl avatar image
tdl answered ·

I also remark that the battery is Idle while the grid is covering the consumption at peak price.

current.png


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Dirk-Jan Faber (Victron Energy) avatar image
Dirk-Jan Faber (Victron Energy) answered ·

Those maximum import and export values are definitely wrong. The system calculates with these values and won't ever be able to reach the targets it is calculating, based on those numbers. If you have a three phase 25 A grid connection, 17 kW is a realistic number.

The same goes for the battery charge and discharge power. That is also way too high.

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tdl avatar image
tdl answered ·

Good spot! I missed the k in front of the W ;-) For grid connection, I have more than what my solar panes can produce. Thanks I fixed the values now.

Still I am puzzled to see that during peak hours it consumes grid power while it could throttle the charge of the battery. I would assume the target is to avoid using GRID during peak hours as much as possible.

I will see if with correct parameters it will improve, but that is a weird strategy to me to reduce the cost.

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tdl avatar image
tdl answered ·

Here, the battery was still discharging, with solar production, injecting to grid 4250W (and when you see the economics, it seems suboptimal). Let's see if the correct params change anything there.

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