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If Multiplus get an low battery voltage, it shuts down and come not back again even if the voltage is hight enough again.
The problem still exists even with V502.
Andy from the OffgridGarage has the same problem: https://www.youtube.com/watch?v=iPv_r74vZDo
Only way to get the error cleared is to turn of the multiplus and turn it on again.
There seems to be a firmware problem with firmware v5.0 and higher. Any way to get back to a lower firmware?
is it ok if we look into your system? when did the issue last occur?
Hi,
thanks for the offer.
No problem to look into my Island system. I am currently only using is to charge my EVs.
Last time the error occured at March 11th.
If you want me to I can also charge my EV again and let this run into the error. You will then see that it will stay at the error even when battery is charged again.
What do you need to look into my system? My system ist connected bidirctional viw VRM. Just send me a personal message.
Ok, couple of things:
-the BMS never sends 'DCL=0' even though the battery if fully empty
-The inverter is not properly configured: it's programmed to shut down at 37.2 volt and restart at 43.6 volt
Because the BMS doesn't send a DCL=0 value the inverter goes on until it reaches 37 volts, but before that the BMS disconnects the battery to protect it. Looks like BMS disconnects at 2.5V and reconnects at 2.7V (I'd set this way higher, like disconnect at 2.8V and reconnect at 3.1)
once the system is charged a bit by the sun, the inverter not only gets a low battery alarm but also a 'High DC ripple' warning, this indicates that the battery didn't fully connect again? (only charge port?), inverter tries to start but only MPPT is providing power = fails to start a couple of times / DC ripple indicates this.
Please first properly configure the system, we fully endorse people to build DIY systems, but they have to be setup properly to function as intended.
If any issues remain after this, I'm happy to help.
One more thing: for better loggin / fault finding, please set VRM logging interval to 1 minute.
(I somehow wasn't able to insert screenshots, will try again later)
Thanks for the investigation!
I have changed to the following configuration:
BMS configuration:
Undervoltage 2,6 Volt → ca. 2% of battery
Undervoltage release 2,8 Volt → ca. 5% of battery
Multiplus Inverter config:
DC input low shutdown: 44,8 V (2,8V) → ca. 5% of battery
DC input low restart: 48V (3V) → ca. 9,5% of battery
DC input low pre-alarm 48V (3V) → ca. 9,5% of battery
After this I have charged my EV.
The BMS sends low SOC when it thinks that battery is lower than 10% SOC
Automatic monitoring alarm - Low state-of-charge alarm: Alarm
Battery Monitor - SerialBattery(LLT/JBD) [1]
That is what I expected.
When Voltage drops under 48 Volt, I get alarms from the multiplus:
08:26
Automatic monitoring alarm - Low battery: Alarm
VE.Bus System [290]
08:44
Automatic monitoring alarm - Low battery: Alarm
VE.Bus System [290]
When this occurs the Multiplus turns off and comes up again when Voltage is at 48 volt again.
Ist the this the expected bahaviour? I thought from the configuration that just the inverter turns off but not the whole multiplus.
But maybe the Multiplus is not really off as it will come up again when battery is at 48V.
I use Node Red to reduce the inverter power progressively as the battery voltage drops below 48.0V, down to zero at 47.2 IIRC.
This was done to keep the Pylontechs out of a Low Battery shutdown (which has a large amount of hysteresis so takes quite a lot of charging to reverse) but something similar might work in yr case until it is fixed properly in f/w.
Thanks. Looks like Victron is not reading this forum.
- Any way to report bugs to Victron?
- Any way to downgrade the firmware?
We do read it, but not 24h a day ;)
I'll be looking in to this, we'll test it in the lab asap.
Hi, I have the same problem with a new installed ESS System (MP2-48-5000, Venus OS on RPi and a 9,6 kWh Battery connected via CAN). The system starts with low battery alarm (red led is permanently on), shuts down immediately and repowers with red led after 30 sec.
Maybe Mk3 used?
https://community.victronenergy.com/questions/190864/multiplus-2-483000-unexplainable-low-battery-alarm.html?childToView=191687#answer-191687
Yes I am using the MK3 Device from Raspberry with Venus OS to the MP2. Is that a problem?
Sure. Reread that thread pls. Note that I don't think that it's good :)
From Alexandra:
When you connect the mk3, the gx is disconnected so the discharge and charge signal from the battery is disconnected.
The systen will shut off. This is a safety feature for systems with can connected battery and DVCC as the battery controls the system.
Plugging in the mk3 is the reason.
This happens on pylon systems as well
What I don't understand is how does Victron find it acceptable that when you require to pull the settings file, look at settings or work on settings - it is ok that the system goes down into Low Battery. These systems are there and in a lot of cases are running critical loads.
There should not be an option that says only do it via mobile or only do it via VRM or only via MK3. The reality is that MK3 was brought on to the market specifically for this - is it depreciated now for systems with DCVV & lithitum batteries?
Not sure why so many adjustments would need to be made to a system. Usually it is one or two revisions maybe, then the system is set for a long time.
One can argue the "Certified Victron" installers would not need this and I have had 4 to my system each time same thing and use MK3. Eventually had to have the country manager of Victron get involved.
So yes theoretically that's how Victron intends it to be reality not so much. Regardless there is a design fault that the system fails because you busy connected to it this is one of the only systems, I know that has this effect, in addition (I could be wrong happy to be pointed somewhere) there is no official documentation that actually describes this "Feature".
More often than not, the defaults in the inverter aren't set or are too high, so when the system loses external control it cuts out, having reverted to internal settings.
More often than not "faults" are just a result of configuration and other customised choices.
Happy to be completely wrong and learn.
At full charge, what could be happening, is that the loss of charger coordination is causing an already full battery to be charged beyond what it is wanting, triggering the BMS to protect. You could repeat the test at a lower state of charge, checking all the charge profile settings in the mppts and inverter (voltage too high etc). You could also try test with the mppts powered off so there isn't any charge source available.
Something additional that also occured together with this error for me and also for Andy of the OffgridGarage. After the red low battery is turned on and stays even after battery is charged again, there will be a new multiplus device at the VRM.
Andy also reported this at his Youtube channel.
There would be lot of more old devices if I did not delete them in the past.
Very strange: This happened all times except the last time.
There are alot of MP2 systems out there without the issue you are describing.
So what needs to happen is working out the difference between user settings, install issues, battery issues, hardware issues and if the firmware now maybe has an issue. Or if a fix can be made to accomodate the shear number of variables for all the unique installs.
Again an intermittent issues (as in one that does not occur in every system) is not easy and will take time. Constructive talk is useful but the me too comments dont fall under that category. More information about the systems, settings and build are needed and also anything you may have tried to do to troubleshoot your own install.
For example the low battery warning can be triggered by the dynamic cut off in ESS assistant. It is also triggered in the inverter tab by the low dc warning and restart values.
It can also be triggered by dc ripple. Which leads to incorrect readings by the inverter on the voltage.
Just to let you know. After changing the parameters of the BMS and Multiplus configuration to assure that the Multiplus shuts down before BMS, I do no longer have the Problem.
My current working very well configuration is for my 48 Volt LiFePo4 system:
- BMS:
• Undervoltage 2,6 Volt
• Undervoltage release 2,8 Volt
- Multiplus:
• DC input low shutdown: 44,8 V (2,8V)
• DC input low restart: 48V (3V)
• DC input low pre-alarm 48V (3V)
Problem occures if BMS shuts down because of low voltage and Multiplus tries to start from MPPT power in the morning when battery still is on shutdown. In this case the multiplus tries to start, but it dows not have enough power. In this case battery will be charged, but when Multiplus comes up there is still not enough power to start. A multiplus does not work if it dows not have a working battery with enough power. It even does not detect that it has a working battery.
Thanks to Victron.
Louis https://github.com/Louisvdw/dbus-serialbattery is working very well.
