question

Frank avatar image
Frank asked

Lithium battery voltage below < 12 volt @ 41% SOC and BMS shutdown @ 39% SOC / 11.2 volt

I have a system with 2 x 330AH smart lithium batteries = 8 kW

12 volt system

I thought i could discharge to 5% SOC, but at 40% the voltage drops below 11.2 Volt and i have a BMS shutdown. With no big loads connected at the moment.

Charging from 40% to 100% was done in 2 hours @ 195 amps = 4.6 Kwh

Which means the capacity of my victron smart lithium batteries is comparable to lead acid batteries.

Is this a manufacturing problem? or could it have anything to do with my parameters.

The batteries where fully charged a couple days ago and both balanced.
Decreasing the BMS shut down voltage does not look to make any difference, with this rapidly declining voltage.

From 45% SOC the batteries voltage is rapidly declining, so it's looks very empty.

So it looks like i got batteries of 200 AH instead of 330AH.

4600/0.95/2/12=201AH

Below some graphs, the shutdown was @ 05:51

The characteristic of this new batterie looks in no comparison to the graph from the manual.


naamloze-afbeelding.png


1653997193487.png

batterie-shutdown.png


2022022401 - Bootschappen-1.pdf

system-overview.png

screenshot-20220531-155601-comvictronenergyvictron.jpg


screenshot-20220531-155606-comvictronenergyvictron.jpg

screenshot-20220531-155611-comvictronenergyvictron.jpg

voltagebattery system voltage
naamloze-afbeelding.png (52.9 KiB)
1653997193487.png (95.2 KiB)
batterie-shutdown.png (48.3 KiB)
system-overview.png (234.5 KiB)
screenshot-20220531-155601-comvictronenergyvictron.jpg (297.1 KiB)
screenshot-20220531-155606-comvictronenergyvictron.jpg (164.4 KiB)
screenshot-20220531-155611-comvictronenergyvictron.jpg (91.5 KiB)
2022022401-bootschappen-1.pdf (372.7 KiB)
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Stefanie (Victron Energy Staff) avatar image Stefanie (Victron Energy Staff) ♦♦ commented ·
@Frank

Please provide us with more information about your system.

What is the BMS? How do you measure voltage and calculate SoC? What are your permanent loads etc.?

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Frank avatar image Frank Stefanie (Victron Energy Staff) ♦♦ commented ·
@Stefanie I have uploaded the single line installation drawing. I have a VE.bus BMS and a BMV-712, Quattro 12/5000/220, Cerbo GX, all just installed together.
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Frank avatar image Frank Stefanie (Victron Energy Staff) ♦♦ commented ·
@Stefanie my permanent loads are two refrigerators, approx 110 Watts AC en 60 Watt DC, what was also running during the night before the voltage drop and shutdown.
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1 Answer
Stefanie (Victron Energy Staff) avatar image
Stefanie (Victron Energy Staff) answered ·

@Frank

Looking at your battery monitor settings, it may well be that the battery monitor synced to 100% too early the last time the batteries were fully charged.

Try raising the charged voltage (Geladen spanning) to 14.0V. This will make the battery monitor sync to 100% when the battery can be considered almost full.

Please let us know if it works for you.

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Frank avatar image Frank commented ·
@Stefanie oke i will try this
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seb71 avatar image seb71 commented ·
Also the actual battery charging voltages (in the MPPTs and in the inverter) are most likelly set too low.
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