ESS Minimum SOC (Unless grid fails) 15% But stops by around 50%?

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alex019 asked Dec 13, '23

ESS Minimum SOC (Unless grid fails) 15% But stops by around 50%?

I have been experiencing the following problem for a few weeks now.

At ESS I have: Minimum charging status (unless the electricity grid fails) 15%. and Set power supply 0W

When power is required, it will first come from the batteries until they are equal to or lower than 15%.

This worked well, but now the battery power keeps stopping between 45 and 50%. If there is a power failure after this, then the system breaks down! The system apparently thinks the batteries are empty?.

The system I have running is as follows:

3x Victron Multiplus-II 48/8000 3 phase setup.

1x ET340 Electricity Meter (Multi-phase)

1x BMV-700

1x CerboGX

1x SmartSolar MPPT 250/70 (4000Wp)

1x Fronius Symo 6.0-3-M (Connection IP (sunspec)) On AC output

1x Aurora Power One 4.2 Inverter 1 phase on AC output. (Will be replaced in the near future by a Fronius symo)

3x Overkill Solar BMS (16s 100A) with 3x USB Module for BMS. Considered as SerialBattery(LLT/JBD)

3 sets of 16 cells LifePo4 280Ah. Is 3x280Ah=840Ah total.

Firmware:

CerboGX: v3.13

Multiplus: 508

SerialBattery(LLT/JBD): 1.0.20230531

BMV-700: v3.11

SmartSolar MPPT 250/70: v3.13

Fronius: 0.3.30.0

Fronius DataManager: 3.28.1-3

The reason for 3x BMS instead of 1x is that you can now charge and discharge with 3x100A (300A) instead of 1x100A.

I got the BMS visible in Cerbo by using the Louisvdw/dbus-serialbattery driver.

This is the latest release! Installed via SSH and Root access:

wget -O /tmp/install.sh https://raw.githubusercontent.com/Louisvdw/dbus-serialbattery/master/etc/dbus-serialbattery/install.sh

bash /tmp/install.sh

Addition: When I set a planned charging level with a SOC limit of 100%, the batteries are charged with approximately a maximum of 110A. Before the problems arose, it was (depending on the charging status) around 300A.

What I have done so far to get the problem resolved:

I used Latest Release candidate for the Cerbo. But now back to the stable due to problems.

With VEConfigure3 the 3 multiplus units were reconfigured with the ESS Assistant again.

I also reset the CerboGX to factory settings using venus-data.tgz.

After this, the Cerbo was set up step by step.

Update Louisvdw/dbus-serialbattery driver to the newest (1.0.20230531) on this moment.(>= V1.0) (Not the Nightly build!)

Unfortunately everything without results.

ess discharging

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JohnC ♦ commented · Dec 16, 2023 at 04:57 AM

@Alex019

The trigger points in your pics appear to be default values. So not set too high. The 43.6V is the one providing a 'Warning'. The 37.2V one is the lowest possible to set, and hasn't been reached if the Multis don't show shutdown advice. By then the batt bms is likely initiating your 'system breaks down!'

I'm thinking load spikes from something like an electric motor starting (bad start capacitor, etc). Often too fleeting for Victron recording to pick up. But I don't know what you're running.

A 'bounce back' V maybe something like the 52.6V in your pics. I don't know your batts either.

So maybe it isn't an SOC thing. But I'd still ditch the Multi (VE.Bus) SOC and go with the BMV. We'd need to see the settings, but likely just syncing to 100% too early. A little tricky to set that up with Li batts, but the manual can help there.

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Alexandra ♦ JohnC ♦ commented · Dec 16, 2023 at 05:24 AM

What C rating discharge voltages are set in the ESS assistant.

Does the voltage on the battery bank collapse under high loads?

The values in ESS also determine where your inverter determines alot of things based on the load.

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alex019 Alexandra ♦ commented · Dec 16, 2023 at 11:15 AM

Where can I find the C rating setting?

No, the voltage does not collapse under heavy load! (by 14000w or more from the battery to the 3x multi)

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ve-configure3-settings5.jpg (72.1 KiB)

alex019 JohnC ♦ commented · Dec 16, 2023 at 10:05 AM

My entire house installation is connected to AC2 out. Including a 1 phase heat pump for tap water, a 3 phase heat pump for underfloor heating, an electric hob, a dishwasher and a dryer.

However, the system stops by default at about 48% to 50% battery low level.

And often the "heavy" devices are not on at that moment or have been switched on for a while.

The batteries I use are: Grade A EV LF280K 6000 cycles lifepo4 3.2V 280Ah battery

1 bank of 16 cells and that 3x (3 banks) each with its own BMS 3x Overkill Solar BMS (16s 100A) with 3x USB Module for BMS. Considered as SerialBattery(LLT/JBD) This information is in the initial post.

Syncing to 100% too quickly/early is probably due to the solar panel power. This usually happens on sunny days.

Which manual describes how to set this up? It is a pity that all the information from the BMS

(which is much more detailed and accurate cannot be used)

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Modifications Space

Node Red Space

Answer 1 · 2023-12-14T13:02:45Z

JohnC answered · Dec 14, 2023 at 01:02 PM

@Alex019

Given you have a BMV in the system, I presume that's where you are deriving the SOC. There are potentially other sources, and being a calculated figure, please confirm. This is where I'd start looking. And yes, it's very possible that the BMV has drifted or prematurely synced, thence providing an overstated figure.

Can you provide a screen snip of the settings? And anything else relevant to how you handle that SOC.

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Answer 2 · 2023-12-14T17:12:32Z

alex019 answered · Dec 14, 2023 at 05:12 PM

The Battery monitor is currently the Multiplus-II. However, I also had 1 of the 3 BMSs as a battery monitor.

I did not use the BMV700 as a battery monitor because it sometimes showed 100% too quickly.

When the problem occurs, the BMV700 also indicates around 50% capacity.

This also applies to the Multiplus and the BMS.

DeviceList

BMV700

BMV700-Device

Settings-SystemSetup-BatteryMonitoring

ESS-Settings

device-list.jpg (51.1 KiB)

bmv700.jpg (47.9 KiB)

bmv700-device.jpg (45.3 KiB)

settings-system-setup-battery-monitoring.jpg (51.2 KiB)

ess-settings.jpg (55.9 KiB)

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Alexandra ♦ commented · Dec 14, 2023 at 05:38 PM

The inverter Ve Bus as a battery monitor does not work well especially If the system is not getting up to 100% SOC And being held there everyday.

You will see it in the voltages. So ignore percentage for now.

Sort out the BMV Sync problem. Then the SOC issue will be solved. (Although the 500A shunt is marginal for the 3 x 8kva system is that the shunt you have?)

Share the settings here and we can see why it is being falsely triggered.

How do you have grid on AC I put 1&2 by the way?

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alex019 Alexandra ♦ commented · Dec 14, 2023 at 08:03 PM

I have the 3 phase grid connection on AC IN (1 phase per unit)

The house installation is on AC Out 2 (Critical load/switchedLoad)

Also the Fronius symo and the Power One Aurora inverter.

The Shunt is a 500A. The system may (if I remember correctly) supply a maximum of 110A charging current per Unit. Total 330A

The BMSs can charge and discharge at 100A each. This is 300A at a time.

A shunt of 500A seems more than sufficient to me. I have (fortunately) never exceeded 300A total.

If any information is missing, I would like to know what information is still missing.

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devicelistbmv.png (37.8 KiB)

bmv700.png (25.3 KiB)

bmv700-alarms.png (30.3 KiB)

bmv700-device.png (29.6 KiB)

Answer 3 · 2023-12-14T21:00:17Z

alex019 answered · Dec 14, 2023 at 09:00 PM

I don't think the BMV700 is the problem. I see on the https://github.com/Louisvdw/dbus-serialbattery/ forum that they actually advise NOT to use the BMV700 for battery monitoring.

I also found the following:

In the multiplus-II AlarmSetup, Low Battery Voltage was set to off. Turn this on and then get a Low battery voltage. The moment this occurs, the discharge stops. (at approximately 50% battery capacity)

However, when I look at the alarms and the CellVoltages of the BMSs, I see no reason why the Multi gives this alarm.

BMS1Alarms

BMS1CellVoltage

BMS2Alarms

BMS2CellVoltage

BMS3Alarms

BMS3CellVoltage

When I charge the batteries with about 10% (to about 60%), the system works again up to about 50% and the Low Battery voltage alarm occurs again.

So I don't know where this alarm comes from or is caused by!

The battery data comes via the driver of Louisvdw/dbus-serialbattery from the BMS

lowvoltagealarmmultiplus.png (36.9 KiB)

multiplus-ii-alarmsetup.png (42.2 KiB)

bms1alarms.png (30.3 KiB)

bms1cellvoltage.png (38.3 KiB)

bms2alarms.png (30.6 KiB)

bms2cellvoltage.png (38.6 KiB)

bms3alarms.png (30.7 KiB)

bms3cellvoltage.png (38.6 KiB)

multiplus-ii-alarmstatus.png (32.6 KiB)

multiplus-ii-alarmstatus2.png (32.4 KiB)

multiplus-ii-novebusalarm.png (18.1 KiB)

multiplus-ii.png (28.9 KiB)

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JohnC ♦ commented · Dec 15, 2023 at 04:47 AM

@Alex019

The warnings/shutdowns are seemingly coming from the Multis. Your system is running big amps and the trigger points may be set too high to handle a large load. Even wiring resistance could be part of it. Like do the batteries bounce back to a good V if you remove loads? VE.Configure is needed to adjust them.

I'd disable the VE.Bus SOC and concentrate on the BMV. In theory the battery bms would be treated as gospel, but if you can't get that across to ESS then a bit pointless.

The BMV settings are available using Victron Connect (via VRM), and likely need some attention before you gain confidence in them.

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alex019 JohnC ♦ commented · Dec 15, 2023 at 08:12 AM

Which trigger point is too high? Which one do you mean?

The system has been running for about 1.5 years. And until a few weeks ago, there were no problems! Cabling has always remained the same. Between the Multi's and the Busbar these are equipped with 2x 50mm2 (per unit) and max length of 2.5 meters.

I used VE Configure! See the screenshots below! Note: These are made offline of the saved config file!

"Like do the batteries bounce back to a good V if you remove loads?"

What is a good V in your mind? And which loads do I need to delete? I've already had AC2 disconnected, but then the system stays in Idle.

Which VE.Bus SOC you mean? And what could be wrong with the BMV700?

If the alarms are coming from the Multi, why look at the BMV700 and not the Multi?

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ve-configure3-1.jpg (65.1 KiB)

ve-configure3-2.jpg (55.5 KiB)

ve-configure3-2a-default.jpg (81.0 KiB)

ve-configure3-3.jpg (69.5 KiB)

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Alexandra ♦ alex019 commented · Dec 16, 2023 at 01:42 PM

Low battery warnings can come from the dynamic cut off values in ESS. What have you set there?

What is your battery operating voltage range? A good voltage is dependant on knowing that and is different for every battery bank.

If you pull the C rating of the battery what is the start voltage (before load) then the voltage under load?

Is there a big difference?

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alex019 Alexandra ♦ commented · Dec 16, 2023 at 06:51 PM

"battery operating voltage range"

Were can I find that? Is is display in this screenshots below?

"If you pull the C rating of the battery"

Where can I change the C value in the settings? If this is the ESS assistant in the VE configurator, then this cannot be adjusted because the multis will then restart. And a 3-phase heat pump does not like that in operation. (Chance that it will become defective)

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ess-dynamiccut-off.jpg (82.8 KiB)

batteryoperationgvoltage1.jpg (71.4 KiB)

batteryoperationgvoltage2.jpg (73.6 KiB)

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