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gdhondt avatar image
gdhondt asked

Running Dynamicc ESS, Cant reach the maximum Charge Current Level

Hi,

My setup:

  • 3 phase Multiplus II 48/5000
  • 45kWh Battery capacity
  • Running Dynamic ESS
  • Location: Netherlands
  • Max grid current 3X 25A = 17000Watt


I have a question about the maximum charge current of my system. My system is not charging maximum watts/amps what the system is able to do. The multis should be able to charge 3X70A=210A. While the system in the VRM does not reach 180A of charging current.


I have the following options/settings enabled/disabled:


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Parameters from my BMS (seplos)


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Even if i make my 'grid setpoint' 14000 watts. It still charge my battery with maximum of 9500 watts.

Does anyone have any advice on what I can check? With the Dynamic ess function, I want to use my system as optimally as possible


charge current limit
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2 Answers
mableeker avatar image
mableeker answered ·

What are your settings for DESS (in VRM or Nodered). The to/from grid and to/from battery variables are determining the charge amps, not the grid setpoint for as far I know now.

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

Can you set your systems VRM logging interval to 1 minute instead of 15 minutes.? That way we get some more data to analyze.

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gdhondt avatar image gdhondt commented ·
Hi Dirk-jan,


I have set the vrm logging interval to 1 minute. :)


My Dynamic Ess Settings are now set to my maximum charge capacity (9800 watts) otherwise my DESS charge calculations doesn’t match the reality.

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Dirk-Jan Faber (Victron Energy) avatar image Dirk-Jan Faber (Victron Energy) ♦♦ gdhondt commented ·

I did talk to one of my colleagues and he said that the 70A max is at 25°C, and it derates pretty quickly from there. It is pretty typical to see 63A or so per unit (10% down), multiply by 3 and you are around 180A.

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gdhondt avatar image gdhondt Dirk-Jan Faber (Victron Energy) ♦♦ commented ·

Hi Dirk-jan.

Still have the issue with reduced charging current

I noticed that if I make my battery monitor “multiplus” visible. Then you see the system thinks it is charging the battery with 10000 watts.


So it looks like there is a bug in the charging monitoring. That’s why the system never reach the maximum charge current of 210A

I think that My reduced charging current is not temp related.



img-5481.jpeg

I’m running DESS. But DESS doesn’t affect the max charging current by switching DESS on or off.

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Dirk-Jan Faber (Victron Energy) avatar image Dirk-Jan Faber (Victron Energy) ♦♦ gdhondt commented ·

The smartshunt is more accurate than the multiplus.

160A out of the potential of 210A, is 76%, which suggests an operating temperature of around 60°C. Also see here: https://www.victronenergy.com/upload/documents/Output-rating-operating-temperature-and-efficiency.pdf

Note that the temperature is the temperature within the Multiplus and not the ambient temperature.

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