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elel asked

SoC jumped to 100% while the battery was being discharged


I have the following simple setup with ESS Assistant in which I charge the battery from the grid during low rate period at night and then use the battery for the house loads during day time.

configuration-diagram.jpg


I encountered a problem in which the SoC shown in the VenusOs screen jumped from 69% (Main On+Absorption LED “ON”, Inverter On LED “Blink”):


soc-jump-1.jpg


suddenly to SoC 100% (Main On+float LED “ON”, Inverter On LED blink):


soc-jump-2.jpg


while the battery was being discharged!

The battery pack has its own BMS and the BMS has no connection to the MP-II.

I set the "State of charge when Bulk finished " to 90% in VEConfig and it worked properly.

I set the "Minimum SoC (unless grid fails)" in ESS to 10% and it worked properly.

The “Float Voltage” set in VEConfig was 52V. The above problem occurred at 53.2V .


Any advice on:

Why the Float LED suddenly lighted up?

Why the SoC suddenly jumped to 100%?


SOC
configuration-diagram.jpg (59.5 KiB)
soc-jump-1.jpg (13.8 KiB)
soc-jump-2.jpg (13.6 KiB)
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Paul B avatar image Paul B commented ·

Hi we would need more setup information to be bale to help you

Please send setting pictures on the Muttiplus ve configure settings one screen shot for each of the screens - also in the GX please send the system setup setting showing the battery monitor selected
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elel avatar image elel commented ·


The same problem happened again today in which the SoC suddenly jumped to 100%SoC.

After the sudden jump-to-100%-SoC problem last night, the system failed to execute the scheduled charging after mid-night and then did a list of erroneous actions after that…… (but these are not the subject of this thread and I will handle them later, just in case they are related to this one).

I somehow was able to schedule the changing during daytime. The battery then discharged as expected but then jumped to 100% SoC from 80% just like what it did last night. Here is the link to a short video which shows what happened.

https://drive.google.com/file/d/1NUdbynsnhQS0EemTmcZi3BBPSp2uKSzK/view?usp=sharing


Any help or advice would be very much appreciated.

(Note: after the setup of the ESS, it was the 2nd time I discharged the battery from the end-of-bluk-charge status and in both cases this problem occurred.)

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Paul B avatar image
Paul B answered ·

If you look at your video you will notice that it switched from Absorption to float on the multiplus loghts then the SOC flipped to 100% -

So I would think that the Multiplus was ending the absorption phase of its charging cycle as its held the battery voltage at 55v for 1 hr as set and is now changing to float mode of 52v, at that point the SOC is changed to 100% as the battery is full.

The small discharge is occurring because the absorption voltage is 55volts and float is 52 so you will see a negative amps figure until the float voltage reaches the set point set being 52 volts.


well thats my thoughts as to why


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