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Discharge power

9 Posts
2 Users
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Topic starter

I am using type47b as a battery and Type48c as inverter and FSOC as controller.
I don't know why it doesn't give me the power from battery as an output, the simulation just gives me the data of the dumped power the inverter discharges when the battery is full

2 Answers
0

@mrquack  The output power (the power drawn from the battery) is an input to the model so it is not included among the model's outputs. A positive value of the single input indicates that power is being added to the battery. A negative value tells the battery that power is being drawn from it. The model performs an energy balance to determine where the battery is between its completely charged and completely discharged state. If the battery keeps getting charged when it is full then the model reports how much energy had to be dumped. If the battery keeps getting discharged when it is empty then rather than generating an error that would stop the simulation the model will report the amount of energy that the battery could not provide.

kind regards,

 David

  

MrQuack Topic starter 11/05/2024 10:00 am

@davidbradley I don't know why but it works now , it seems the problem was the fsoc, when the fsoc became more than 1 the battery stopped to generate an output and there is only the dumped power from the inverter type48c .
I have another question: the value of the discgarge power depends on cell in series and the voltage of the single cell, is it possible to change such parameters?

0

@MrQuack I am afraid I don't quite follow your question. Are you asking whether it is possible to change the number of cells in series or the characteristics of a single cell so that it has a different voltage? Yes, it is possible. The number of cells and the resting voltage of a single cell are parameters of the battery model so they can be set and changed but they will then remain constant throughout the simulation. Normally the discharge power does not depend on the battery since the value of the discharge power is in input to the battery model. Of course if you specify a small battery and a very large discharge power then the model will run into trouble and you should probably increase the number of cells in series and parallel.

My apologies if I misunderstood your question. If so, could you please give me a bit more detail so that I can try and answer a bit better?

kind regards,

 David

 

MrQuack Topic starter 14/05/2024 8:56 pm

@davidbradley more cells in parallel should give me more capacity, meanwhile more cells in series should give me more power as output .

MrQuack Topic starter 14/05/2024 8:59 pm

@davidbradley i changed the number of cells in series and parallel.

DavidBradley 15/05/2024 12:29 pm

@MrQuack I agree that adding more cells in parallel should give you more capacity. However, the number of cells in parallel and series won't affect the output power because the model doesn't calculate the output power. You (meaning the user) tell the model what the output power is. It's a bit like if you had a water tank. Changing the number of battery cells in parallel in series is akin to changing the volume of the tank, not to changing the rate of liquid flowing out of the tank; that has to be specified separately.

I think perhaps it might be a good idea to address the issue with your TRNSYS distributor so that they can look at your project directly and try to clear up the issue. If you can please send an email to techsupport@tess-inc.com and include the contents of your userXX.id file (located in the .\TrnsysXX\ folder and opened with a text editor) then they'll be able to direct you to your distributor for assistance.
kind regards,
David

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