question

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dominik-feser asked

ESS or MP2 reducing discharge power at 30% and 20%

Hi all,

I am a bit confused because my MP2 reduces the discharge current at 30% and then again at 20%. I cant recall to have configured something like this.

Environment is MP2 48/5000 + Venus OS + 16s DIY System with JK BMS.

Can anyone point me to a possible source?

Multiplus-IIESSVenus OS
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2 Answers
nickdb avatar image
nickdb answered ·

If you are referring to the battery DCL, assuming your BMS appears on the GX and is in control, then that is determined by your BMS which, as the SOC drops and cell imbalances and voltage drop, possibly, occur, it will step down the current.

Sort of the reverse of dropping charge current as the battery becomes full.

In this instance the system just follows instructions.

Welcome to the wonderful world of DIY batteries.

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dominik-feser avatar image
dominik-feser answered ·
2 comments
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1234enough avatar image 1234enough commented ·
I just went through a purposeful discharge to low 2.6v @ cell for testing purposes.

Had fun and games as the JK bms kept reporting ( bms data connected to multiplus ii with RS485 - USB)very low SOC which kept stopping discharge from the multiplus.

Only way I found to overcome this was to keep changing on the JK bms the rated battery AH to a higher figure, then changing it back to 280AH, this reset the SOC which allowed discharge to continue.


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nickdb avatar image nickdb ♦♦ 1234enough commented ·
2.6V is crazy low, of course it should be reporting very low SOC and blocking discharge to protect the cells.

That would equate to 41V on a 48V nominal pack.

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