[Multiplus II 3p ESS / LiFePO4 / 123\SmartBMS] Low Battery Warnings

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styrx asked Jun 7, '22

[Multiplus II 3p ESS / LiFePO4 / 123\SmartBMS] Low Battery Warnings

Hi,

I set up a 3-phase ESS system with 3 Multiplus II 5000, 16 EVE LiFePO4 cells and a 123\SmartBMS.

Since the beginning, however, I have had the problem that I keep getting "low battery L1" warnings, mainly in the early hours of the morning.

Using the VRM export, I tried to understand whether there was a connection between the voltage and the low battery warning; but couldn't find any.

Anyone have any tips as to why the warnings are occurring?

Is there a log that could be evaluated to find out why the warnings are being issued?

Below are the settings in VE Configure and the VRM export with all relevant rows and columns.

Thank you for your help in advance!

Hallo,

ich habe ein 3-phasiges ESS-System mit 3 Multiplus II 5000, 16 EVE LiFePO4 Zellen und einem 123\SmartBMS aufgebaut.

Seit Anfang an habe ich allerdings das Problem, dass mir immer wieder, hauptsächlich in den frühen Morgenstunden, "low battery L1" Warnungen angezeigt werden.

Ich habe versucht anhand des VRM-Exports nachvollziehen zu können, ob es Zusammenhänge zwischen Spannung und der low battery Warnung gibt; konnte aber keine finden.

Hat irgendjemand Tipps, warum die Warnungen auftreten?

Gibt es ein Logbuch, dass man auswerten könnte, um zu erfahren, warum die Warnungen ausgegeben werden?

Nachfolgend die Einstellungen im VE Configure und den VRM-Export mit allen relevanten Zeilen und Spalten.

Vielen Dank für eure Hilfe im Voraus!

Multiplus-II low battery warning

ve-conf.png (145.1 KiB)

vrm-exp.png (609.9 KiB)

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Modifications Space

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Answer 1 · 2022-06-08T09:29:37Z

styrx answered · Jun 08, 2022 at 09:29 AM

Could the "dynamic voltage cut-off" be the reason for the "low battery" warnings?

I'm using Victron's default setting:

0.005C  = 52V
0.25C   = 50V
0.7C    = 49.2V
2C      = 48V
Sustain = 50V

The following topic in the powerforum discusses reducing the "dynamic voltage cut-off":

https://powerforum.co.za/topic/6320-victron-ess-dynamic-cut-off-config/

Does the suggestion

0.005C  = 50V
0.25C   = 48.8V
0.7C    = 48V
2C      = 47V
Sustain = 49V

make sense?

Or is the suggestion not using the dynamic curve and just set everything to 49V better?

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Answer 2 · 2022-06-08T10:22:35Z

klim8skeptic answered · Jun 08, 2022 at 10:22 AM

A 280ah battery is very small when connected to 3 x 5000 multiplusII.

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Answer 3 · 2022-06-08T12:13:22Z

styrx answered · Jun 08, 2022 at 12:13 PM

The 5000 has a max. battery charge current of 70A.

3x 70A = 210A < 1C

for example:

https://greenakku.de/Heimspeicher-Systeme/Victron-Multiplus-II-48V-3-Phasen-15kVA-Speicherpaket-14-4kWh-Pylontech-LiFePO4-mit-Cerbo-GX::3722.html

1

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nickdb ♦♦ commented · Jun 08, 2022 at 12:18 PM

Its nearer 100A discharge per multi, so the pack would need to be able to sustain the better part of 300A to supply 3..

Is this pack capable of that?

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